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GLOBAL STABILITY OF AN EPIDEMIC MODEL FOR VECTOR-BORNE DISEASE

Journal of Systems Science & Complexity 2010年第2期23卷 279-292页

作者： Hongzhi YANG Huiming WEI Xuezhi LI Faculty of Science Xi'an Jiaotong University Xi'an 710049 China. State Key Laboratory of Multiphase Flow in Power Engineering Xian Jiaotong University Xi'an 710049China Department of Mathematics Xinyang Normal University Xinyang 464000 China. Department of Mathematics Xinyang Normal University Xinyang 464000 China

This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is completely determined by the basic reproduction number Ro. If Ro ≤ 1. the diseasefree equilibrium is globally stable and the disease dies out. If Ro 〉 1. a unique endemic equilibrium is globally stable in the interior of the feasible region and the disease persists at the endemic equilibrium. Numerical simulations are presented to illustrate the results.

关键词： Basic reproduction number endemic equilibrium epidemic model global stability vectorborne disease.

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Simulation of turbulent mixing layer flow by vortex method

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Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University 2010年第11期44卷 87-91页

作者： Ma, Mingxian Chen, Bin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Turbulent mixing layer flow was simulated by the discrete vortex method, and viscosity was modeled by the random walk method and the solid wall was represented by the vortex sheet in the simulation. The predictions of the profiles of mean velocity and turbulent flow parameters agree well with experimental data. The results show that the peak value of Reynolds shear stress increases but the fluctuations of the peak value occur because of vortex-pairing, and vorticity peak value increases in the downstream direction. Then the effect of Reynolds number on the distribution of the turbulent flow parameters at the same velocity ratio was explored. It seems that the peak values of Reynolds shear stress under different Reynolds numbers will increase at the similar slope in the downstream direction. The average vorticity peak value will decrease in the downstream direction, and the decrease rate will increase with Reynolds number. In addition, the vorticity peak value in each section will increase nearly linearly with Reynolds number.

关键词： Vorticity

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flow visualization of erythrocytes motion and deformation in microchannel

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2010年第4期31卷 621-624页

作者： Guo, Fang Xiang, Hao Chen, Bin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The dimension of erythrocyte is close to capillary diameter and in microcirculation blood should be treated as a two-phase flow system, i.e., erythrocytes suspended in plasma. The rheological property of erythrocytes will significantly influence the hemodynamics. In our experiment, the motion and deformation of erythrocytes in a microfluidic chip with rectangular cross-section microchannel was captured by optical microscope and high speed CCD camera. The aggregation, deformation and common movement forms of erythrocytes were observed under different viscosity, hematocrit and velocity. It was found that erythrocytes behaved a regular biconcave disc shape at low velocity and low-to-medium viscosity, and always rolled and rotated themselves in their movement. At high velocity and medium viscosity, RBCs elongated obviously along the flow direction and presented a flat oval shape together with a tank-treading motion (TTM).

关键词： Microfluidic chips

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Effect of Slug flow on CO2 Corrosion

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AIP Conference Proceedings 2010年第1期1207卷 403-409页

作者： Y. B. Zhang K. Yan D. F. Che State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

multiphase {1. induced CO2 corrosion has resulted in serious losses in oil and gas production. In this paper, gas‐liquid two‐phase vertical upward slug {1. has been analyzed from aspects containing {1. structure, hydrodynamic characteristics, mass transfer characteristics and their effects on pipe wall and corrosion product film, and it is found that slug {1. has a distinct effect on transports of corroding species to and of corrosion products from the wall, momentum interchange between fluid and wall and the formation and damage of corrosion product film. In addition, the transports of corrosive species and corrosion product are also an important step in CO2 corrosion process. It is assumed that the slug {1. induced CO2 corrosion of pipeline is dependent on the non‐linear coupling of the characteristics including the shear stress, the normal stress, the mass transfer coefficient, and the electrochemical reaction.

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Experimental study on CCl_4/CH)4/O_2/N_2 oxidation

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Science China(Technological Sciences) 2010年第4期53卷 1016-1022页

作者： WANG Bo1.2,CHI Yong2,YAN JianHua2 & NI MingJiang2 1.College of Energy and power {1.,University of Shanghai for Science and Technology,Shanghai 200093,China 2 state key laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 31.027,China 1. College of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China2. State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and find incineration process optimization methods for pollution *** reaction temperature varies from 700℃ to 1.00℃ and the CCl4/CH4(or Cl/H) mole ratio of the inlet mixture varies from 0.21.to *** profiles are measured with *** is shown that at the same initial CCl4 concentration and reaction temperature adding CH4 favors CCl4 destruction and CO2 *** the destruction and removal efficiency(DRE) of CH4 decreases with lower Cl/H and higher concentrations of toxic products of incomplete combustion such as COCl2 and CH3Cl are formed at the same *** chlorine in the system favors CH4 decomposition,but it also inhibits further oxidation of *** temperature assists in both CCl4 destruction and CH4 conversion,and the concentration of toxic combustion intermediates is *** the temperature is the most effective way to enhance CCl4 *** CO2 concentration increases with temperature.A CO concentration peak is observed around 800℃:with a certain Cl/H,the CO concentration first increases with temperature and then *** effect of increasing CH4 concentration on CCl4 destruction becomes mild above 900℃.Rather,it enhances the interaction between chlorine and carbonaceous radicals,which leads to higher concentration of toxic products.

关键词： hazardous waste destruction and removal efficiency(DRE) oxidation carbon tetrachloride chlorinated compounds methane

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A model for calculating heat transfer coefficient concerning ethanol‐water mixtures condensation

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AIP Conference Proceedings 2010年第1期1207卷 367-373页

作者： J. S. Wang J. J. Yan S. H. Hu Y. S. Yang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

The attempt of the author in this research is made to calculate a heat transfer coefficient (HTC) by combining the filmwise theory with the dropwise notion for ethanol‐water mixtures condensation. A new model, including ethanol concentration, vapor pressure and velocity, is developed by introducing a characteristic coefficient to combine the two mentioned‐above theories. Under different concentration, pressure and velocity, the calculation is in comparison with experiment. It turns out that the calculation value is in good agreement with the experimental result; the maximal error is within ±30.1.. In addition, the model is applied to calculate related experiment in other literature and the values obtained agree well with results in reference.

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Experimental and numerical study on flow separation control in rectangle diffuser

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical engineering 2010年第5期30卷 92-99页

作者： Xie, Yong-Hui Fan, Tao Zhang, Di Ye, Dong-Ting Wang, Shun-Sen State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi Province China

To investigate the mechanism of active control for flow separation in rectangle diffuser by vortex generator jets (VGJs) method, numerical analysis with large-eddy simulation and experimental measurement by particle image velocimetry (PIV) were carried out for the flow field. The numerical results show good agreement with experimental data. The two dimensional vortical structure was discussed in detail via the analysis of their velocity and vorticity distribution. Based on the three dimensional identification of vortex, several vortical structure, with emphasis on the dynamic process of its generation and development, was also discussed. The results show that the jet shear-layer vortices evolved from vortex loops to vortex rings as time go on. Horseshoe vortices wrap around the jet nozzle have the strong stability. The counter-rotating vortex pair has mean-flow definition although they may also have unsteady components. Moreover, to investigate the effect of VGJs on separation control, the surface pressure coefficient, the length of separation zone, the flow characteristics in diffuser and pressure power spectra were compared with and without VGJs. It revealed the longitudinal vortices generate at the downstream of jet increase cross-stream mixing of streamwise momentum and then suppress or delay the separation in diffuser. © 201. *** ***.

关键词： Large eddy simulation

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First passage failure of dynamical power systems under random perturbations

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Science China(Technological Sciences) 2010年第9期53卷 2495-2500页

作者： CHEN LinCong1.& ZHU WeiQiu2 1.College of Civil engineering,Huaqiao University,Xiamen 361.21.China 2 Department of Mechanics,{1. key laboratory of Fluid power Transmission and Control,Zhejiang University,Hangzhou 31.027,China 1. College of Civil Engineering Huaqiao University Xiamen 361021 China2. Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

The first-passage problem of dynamical power system of a single-machine-infinite-bus (SMIB) system under random perturbations is ***,the stochastic averaging method for quasi non-integrable generalized Hamiltonian systems is applied to reduce the equations of the SMIB system under random perturbations to a set of averaged It ***,the backward Kolmogorov equation governing the conditional reliability function and the Pontryagin equation governing the conditional mean of first passage time are established and solved numerically,***,the proposed method is verified by using the Monte Carlo simulation of the original system.

关键词： dynamical power system random perturbation stochastic averaging first passage failure

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Research on the Preparation of (CuAg)xIn2xZn2(1.2x)S2 Solid Solution Photocatalysts

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AIP Conference Proceedings 2010年第1期1207卷 1066-1069页

作者： K. Zhang D. W. Jing C. J. Xing L. J. Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

ZnS‐CuInS2‐AgInS2 solid solution photocatalysts were successfully prepared by co‐precipitation method with heat treatment under different atmosphere ( N2 and H2S). XRD, XRF, UV‐vis, and SEM were used to characterize the prepared photocatalysts, indicated that the composition of result photocatalysts were different from each other and also the rate of charge, though they possessed a wurtzite‐type phase structure. The photocatalysts all showed photocatalytic activities for H2 evolution from aqueous solutions containing SO32− and S2− as sacrificial reagents under visible light irradiation with Ru loading, but sample treated under H2S atmosphere performed better, the possible reason was proposed.

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Effects of radiation heat transfer space non-uniformity of combustion chamber components on in-cylinder soot emission formation in diesel engine

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Science China(Technological Sciences) 2010年第7期53卷 1824-1832页

作者： Lü JiZu1. BAI MinLi2 & LI XiaoJie1.1.state {1. laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 1.6023, China 2 School of Energy and power engineering, Dalian University of Technology, Dalian 1.6023, China 1. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116023 China2. School of Energy and Power Engineering Dalian University of Technology Dalian 116023 China

Combustion chamber components (cylinder head-cylinder liner-piston assembly-fuel film) were treated as a coupled body. Based on the three-dimensional numerical simulation of heat transfer of the coupled body, the multi-dimensional simulation computation coupling flow and solid on working process and combustion chamber components of internal combustion engine was performed using Discrete Transfer Radiation Model (DTRM) radiation heat transfer model, zoning solution method and boundary coupling method. The simulation was applied to the influence investigation of the space non-uniformity in radiation heat transfer among combustion chamber components on the generation of in-cylinder soot emissions. The results show that the space non-uniformity in heat transfer among the combustion chamber components has great influence on the generation of in-cylinder NOx emissions. The difference value of total soot in cylinder when exhaust valves are opened is 1.3% (no radiation), 0.8% (radiation). So the effect of radiation heat transfer space non-uniformity of combustion chamber components on total soot production can be ignored. While in local area radiation heat transfer space non-uniformity has certain effect on soot production inside whole combustion chamber space, and has less effect on soot production in the area near the wall of combustion chamber components.

关键词： radiation heat transfer space non-uniformity in-cylinder diesel engine

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