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Measurement and simulation of the two-phase velocity correlation in sudden-expansion gas-particle flows

持久性有机污染物论坛2008暨第三届持久性有机污染物全...

作者： Zhi Zhang~1 Liyan Liu~1 Yi-Fan Li~(1,6*) Bing Sun~2 Nanqi Ren~1 Xinnan Wan~3 Diandou Xu~4 Tom Harner~6 Ed Sverko~(5,6) Jianmin Ma~6 (1 International Joint Research Center for Persistent Toxic Substances (ijrc-pts),State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology,china 2 ijrc-pts,dalian maritime university,china 3 ijrc-pts,Chengdu university of Technology,china 4 ijrc-pts,Institute of High Energy Physics,Chinese Academy of Sciences,china 5 ijrc-pts,McMaster university,Canada 6 Science and Technology Branch,Environment Canada

＜正＞*** International Joint Research Center for Persistent Toxic Substances（ijrc-pts）started the Chinese persistent organic pollutants（POPs）Soil and Air Monitoring Program（SAMP）in 2005,which had run on a seaso...

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Acta Mechanica Sinica 2011年第4期27卷 494-501页

作者： Li-Xing Zhou.Yang Liu.Yi Xu Department of Engineering Mechanics,Tsinghua university,100084 Beijing,china Marine Engineering College,dalian maritime university,116026 dalian,china Department of Engineering Mechanics Tsinghua University Beijing China Marine Engineering College Dalian Maritime University Dalian China

In this paper the present authors measured the gas-particle two-phase velocity correlation in sudden expansion gas-particle flows with a phase Doppler particle anemometer （PDPA） and simulated the system behavior by using both a Reynolds-averaged Navier-Stokes （RANS） model and a large-eddy simulation （LES）. The results of the measurements yield the axial and radial time-averaged velocities as well as the fluctuation velocities of gas and three particle-size groups （30μm, 50μm, and 95μm） and the gasparticle velocity correlation for 30μm and 50μm particles. From the measurements, theoretical analysis, and simulation, it is found that the two-phase velocity correlation of sudden-expansion flows, like that of jet flows, is less than the gas and particle Reynolds stresses. What distinguishes the two-phase velocity correlations of sudden-expansion flow from those of jet and channel flows is the absence of a clear relationship between the two-phase velocity correlation and particle size in sudden-expansion flows. The measurements, theoretical analysis, and numerical simulation all lead to the above-stated conclusions. Quantitatively, the results of the LES are better than those of the RANS model.

关键词： PDPA measurement - Simulation Two-phasevelocity correlation Sudden expansion gas-particle flows

Communications and control co-design:a combined dynamic-static scheduling approach

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Science china(Information Sciences) 2012年第11期55卷 2495-2507页

作者： LU ZiBao & GUO Ge School of Information Sciences and Technology,dalian maritime university,dalian 116026,china School of Information Sciences and Technology Dalian Maritime University Dalian China

This paper investigates the problem of joint design of an output feedback controller and the medium access scheduling policy for networked control systems(NCSs).The capacity of communication networks on sensors side and actuators side are limited so that at any time the sensors and actuators cannot be accommodated simultaneously and that transmission delays are *** joint design problem is solved in three steps:determining communication sequences(called feasible sequences) for both sides that can preserve controllability and observability,respectively;designing output feedback controller without considering the effect of communication sequences;and setting up a rule that governs the switching between feasible communication ***,the first step is a static scheduling procedure that yields a set of feasible communication sequences for each *** third step is a dynamic scheduling process resulting in a switching policy in line of a stability criterion of the closed-loop switching delay *** show the effectiveness of the combined static and dynamic scheduling method,a numerical example is also provided.

关键词： controllability observability switching rule medium access scheduling communication sequence

A New Approach to Duffing Equation withStrong and High Order Nonlinearity

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Communications in Nonlinear Science and Numerical Simulation 1999年第2期4卷 132-135页

作者： Jianguo LIN(dalian maritime university, Institute of Marine Environment, dalian 116024, china)E-mail: linjg@*** dalian maritime university Institute of Marine Environment Dalian 116024 China

A new parameter iteration technique is proposed to solve the Duffingequation with strong and high order nonlinearity. Contrary to the linearized perturbation technique parametrized perturbation technique and variational iteration techniqueproposed by J.H. He, the frequency converged asymptotically to the exact result, not aconstant.

关键词： nonlinear Duffing equation parameter iteration method

A New Approximate Iteration Solution ofBlasius Equation

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Communications in Nonlinear Science and Numerical Simulation 1999年第2期4卷 91-94页

An approximate analytical solution of Blasius equation is obtained by theparameter iteration method. The comparison with Howarth’s numerical solution showsthat the accuracy of the proposed method is higher than other approximate analyticalsolutions. Further, we provide also a numerical iteration scheme which is simple, efficientand practical.

关键词： nonlinear problem parameter iteration method Blasius equation

DC dielectrophoresis separation of marine algae and particles in a microfluidic chip

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Science china Chemistry 2012年第4期55卷 524-530页

作者： SONG YongXin1, YANG JianDong1, SHI XiaoFei4, JIANG Hai3, WU YanBin1, PENG Ran1, WANG Qi5, GONG Ning2, PAN XinXiang1, SUN YeQing2 & LI DongQing1,31Department of Marine Engineering, dalian maritime university, dalian 116026, china 2Institute of Environmental Systems Biology, dalian maritime university, dalian 116026, china 3Department of Mechanical and Mechatronics Engineering, university of Waterloo, Waterloo, ON, N2L 3G1, Canada 4College of Information Science and Technology, dalian maritime university, dalian 116026, china 5Department of Respiratory Medicine, the Second Hospital Affiliated to dalian Medical university, dalian 116026, china Department of Marine Engineering Dalian Maritime University Dalian China College of Information Science and Technology Dalian Maritime University Dalian China Department of Mechanical and Mechatronics Engineering University of Waterloo Waterloo Canada Department of Respiratory Medicine the Second Hospital Affiliated to Dalian Medical University Dalian China Institute of Environmental Systems Biology Dalian Maritime University Dalian China

This paper reports a microfluidic method of continuous separation of marine algae and particles by DC dielectrophoresis. The locally non-uniform electric field is generated by an insulating PDMS triangle hurdle fabricated within a PDMS microchannel. Both the particles and algae are subject to negative DEP forces at the hurdle where the gradient of local electric-field strength is the strongest. The DEP force acting on the particle or the algae depends on particles' or algae's volume, shape and dielectric properties. Thus the moving particles and algae will be repelled to different streamlines when passing the hurdle. In this way, combined with the electroosmotic flow, continuous separation of algae of two different sizes, and continuous separation of polystyrene particles and algae with similar volume but different shape were achieved. This first demonstration of DC DEP separation of polystyrene particles and algae with similar sizes illustrates the great influence of dielectric properties on particle separation and potentials for sample pretreatment.

关键词：海洋藻类颗粒分离微流控芯片聚苯乙烯颗粒 DC 连续分离电场强度介电性能

A New Admissibility Condition of Discrete-time Singular Systems with Time-varying Delays

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International Journal of Automation and computing 2012年第5期9卷 480-486页

作者： Yong-Yun Shao 1,3 Xiao-Dong Liu 1,2 Xin Sun 3 Zhan Su 4 1 Transportation Management College, dalian maritime university, dalian 116026, china 2 Department of Mathematics, dalian maritime university, dalian 116026, china 3 Department of Computer and Mathematics Teaching, Shenyang Normal university, Shenyang 110034, china 4 Institute of Systems Science, Northeastern university, Shenyang 110004, china Transportation Management College Dalian Maritime University Dalian China Department of Computer and Mathematics Teaching Shenyang Normal University Shenyang China Department of Mathematics Dalian Maritime University Dalian China Institute of Systems Science Northeastern University Shenyang China

This paper gives a novel delay-dependent admissibility condition of discrete-time singular systems with time-varying delays. For convenience, the time-varying delay is assumed to be the sum of delay lower bound and the integral multiples of a constant delay. Specially, if the constant delay is of unit length, the delay is an interval-like time-varying delay. The proposed admissibility condition is presented and expressed in terms of linear matrix inequality (LMI) by Lyapunov approach. Generally, the uncertainty of time-varying delay would lead to conservatism. In this paper, this critical issue is tackled by accurately estimating the time-varying delay. Consequently, the proposed admissibility condition is less conservative than the existing results, which is demonstrated by a numerical example.

关键词： Singular systems discrete-time delay-dependent admissibility time-varying delay

Structure and photochromic properties of molybdenumphosphoric acid/TiO_2 composite films

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Science china Chemistry 2009年第2期52卷 169-173页

作者： QI He,LIU Yan,FENG Wei & ZHU YiMin College of Environmental Science and Engineering,dalian maritime university,dalian 116026,china College of Environmental Science and Engineering Dalian Maritime University Dalian China

TiO_2 sol-gel composite films with dropping molybdenumphosphoric acid(PMoA) have been prepared by sol-gel *** structure and constitute of composite thin films were studied with Fourier transforms infrared spectroscopy(FT-IR),atomic force microscopy(AFM),and X-ray diffraction(XRD) patterns,*** photochromic behavior and mechanism of composite thin films were inves-tigated with ultraviolet-visible spectra(UV-vis) and electron spin resonance(ESR).FT-IR results showed that the Keggin geometry of PMoA was still preserved inside PMoA/TiO2 composite thin films,and a charge transfer bridge was built at the interface of PMoA and TiO2 through the Mo-O-Ti *** topography of the composite film showed obvious changes before/after adding PMoA,and the surface topography of composite films showed obvious changes before/after irradiating as *** thin film had reversible photochromic *** with UV light,transparent films changed from colorless to blue and they can bleach completely with ambient air in the *** re-sults showed that TiO_2 were excitated by UV light to produce electrons,which deoxidized PMoA to produce *** photochromic process of PMoA/TiO_2 system was carried through elec-tron transfer mechanism.

关键词： molybdenumphosphoric acid TiO2 composite film photochromism

The anharmonic effect study of coupled Morse oscillators for the unimolecular reaction

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Science china Chemistry 2008年第12期51卷 1146-1152页

作者： YAO Li1,2 & LIN Sheng-Hsien2,31 Department of Physics, dalian maritime university, dalian 116026, china 2 Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10764, china 3 Department of Applied Chemistry and Institute of Molecular Sciences, Chiao-Tung university, Hsinchu 30051, Taiwan, china Department of Physics Dalian Maritime University Dalian China Institute of Atomic and Molecular Sciences Academia Sinica Taipei China Department of Applied Chemistry and Institute of Molecular Sciences Chiao-Tung University Hsinchu Taiwan China

The importance of anharmonic effect in dissociation of molecular systems especially clusters has been noted. In this paper, we shall study the effect of coupled anharmonic oscillator of the standard bilinear form (SBF) Morse oscillator (MO) potential on unimolecular reaction. We shall use the systematic theoretical approach, YL method, proposed by Yao and Lin (YAO L, et. al. J Phys Chem A, 2007, 111(29): 6722-6729), which can evaluate anharmonic effects on the rate constants based on the transition state theory. In treating the anharmonic effect with the Morse oscillator potential on unimolecular reactions under collision-free conditions by using the RRKM (Rice-Ramsperger-Kassel-Marcus) theory, the in-verse Laplace transformation of the partition functions was used to obtain the total amount of state and density of state by using the first-order and the second-order approximations of the saddle-point method. To demonstrate the anharmonic effect of the SBF Morse model, we choose some model systems and a real reaction as examples.

关键词： anharmonic effect standard bilinear form Morse oscillator rate constant RRKM theory