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Higher-mode effect on the seismic responses of buildings with viscoelastic dampers

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Earthquake Engineering and Engineering Vibration 2002年第1期1卷 119-129页

作者： Meng-Hao Tsai Department of Civil Engineering Taiwan UniversityChinese Taipei Postdoctoral Research Fellow

In conventional modal analysis procedures,usually only a few dominant modes are required to describe the dynamic behavior of multi-degrees-of-freedom *** number of modes needed in the dynamic analysis depends on the higher-mode contribution to the structural response,which is called the higher-mode *** modal analysis approach, however,may not be directly applied to the dynamic analysis of viscoelastically damped *** is because the dynamic properties of the viscoelastic dampers depend on their vibration ***,the structural stiffness and damping contributed from those dampers would be different for each *** this study,the higher-mode effect is referred to as the response difference induced by the frequency-dependent property of viscoelastic dampers at higher *** analysis procedures for buildings with viscoelastic dampers distributed proportionally and non-proportionally to the stiffness of the buildings are developed to consider the higher-mode *** studies on shear-type viscoelastically damped building models are conducted to examine the accuracy of the proposed procedures and to investigate the significance of the higher-mode effect on their seismic *** damper models are used to estimate the peak damper forces in the proposed procedures. Study results reveal that the higher-mode effect is significant for long-period viscoelastically damped *** higher-mode effect on base shear is less significant than on story acceleration *** difference of the seismic response usually occurs at the top ***,the higher-mode effect may not be reduced by decreasing the damping ratio provided by the viscoelastic *** practical application,it is realized that the linear viscous damping model without considering the higher-mode effect may predict larger damper forces and hence,is on the conservative side.

关键词： model analysis viscoelastic dampers higher-mode effect

Effect of Cambering on the Aerodynamic Performance of Heaving Airfoils

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Journal of Bionic Engineering 2009年第4期6卷 398-404,406-407页

作者： Joel E.Guerrero postdoctoral Research fellow Department of CivilEnvironmental and Architectural EngineeringUniversity of GenoaVia Montallegro 1Genoa16145Italy

In the present work,a parametric numerical study is conducted in order to assess the effect of airfoil cambering on the aerodynamic performance of rigid heaving *** incompressible Navier-Stokes equations are solved in their velocity-pressure formulation using a second-order accurate in space and time finite-difference *** tackle the problem of moving boundaries,the governing equations are solved on overlapping structured *** numerical simulations are performed at a Reynolds number of Re=1100 and at different values of Strouhal number and reduced *** results obtained show that the airfoil cambering geometric parameter has a strong influence on the average lift coefficient,while it has a smaller impact on the average thrust coefficient and propulsive efficiency of heaving airfoils.

关键词： heaving airfoils structured overlapping grids incompressible Navier-Stokes equations airfoil cambering

Velocity Profiles between Two Baffles in a Shell and Tube Heat Exchanger

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Journal of Thermal Science 2015年第4期24卷 356-363页

作者： Tae-Hyun Chang Chang-Hoan Lee Hae-Soo Lee Kwon-Soo Lee Senior Research fellow of RESEAT Korea Institute of Science and Technology Information Korea Institute of Science and Technology Information postdoctoral Research fellow School of Mechanical Engineering of Kyungnam University International University of Korea

Heat exchangers are extensively utilized for waste heat recovery,oil refining,chemical processing,and steam *** this study,velocity profiles are measured using a 3D particle image velocimetry(PIV)system between two baffles in a shell and tube heat exchanger for parallel and counter *** PIV and computational fluid dynamics results show the occurrence of some strong vectors near the *** vectors are assumed due to the clearance between the inner tubes and the front ***,the major parts of the vectors are moved out through the bottom opening of the rear baffle,and other vectors produce a large circle between the two *** simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent *** k-εturbulence model is employed to calculate the flows along the heat exchanger.

关键词： Baffle P1V Shell and tube heat exchanger Cut off ratio CFD

Impurity Deionization Effects on Surface Recombination DC Current-Voltage Characteristics in MOS Transistors

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Journal of Semiconductors 2010年第12期31卷 1-10页

作者：陈祖辉揭斌斌薩支唐 Lee-Kuan-Yew postdoctoral fellow 2007-2010Nanyang Technological University Department of Physics Xiamen University CTSAH Associates Gainesville

Impurity deionization on the direct-current current-voltage characteristics from electron-hole recombi- nation （R-DCIV） at SiO2/Si interface traps in MOS transistors is analyzed using the steady-state Shockley-Read-Hall recombination kinetics and the Fermi distributions for electrons and holes. Insignificant distortion is observed over 90% of the bell-shaped R-DCIV curves centered at their peaks when impurity deionization is excluded in the theory. This is due to negligible impurity deionization because of the much lower electron and hole concentrations at the interface than the impurity concentration in the 90% range.

关键词： recombination current impurity deionization interface traps MOS transistors

INVERSION OF MULTILAYERED VARIABLE DENSITY MODELS AND STUDY OF CRUSTAL AND UPPER MANTLE STRUCTURE

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Science China Chemistry 1990年第8期33卷 1002-1013页

作者：陈胜早 Instisute of Geophysics State Seismological Bureau Beijing 100083 PRC Postdoctoral fellow in Canadian Government Laboratory Ontario Canada.

This paper presents a direct gravity inverse method of multilayered variable density models, and gives gravity forward formulae under various conditions of density-depth functions such as the constant, exponential, linear, sine and cosine, cubic spline, and Fourier progression. The testing of theoretical models and the analysis of real examples have been made for the cubic spline function and have proved that the method is effective. Other formulae can be applied under corresponding conditions by means of optimization or other methods.

关键词： multilayered variable density gravity forward and inverse problems crustal and upper mantle structure optimization

Velocity Profiles between Two Baffles in a Horizontal Circular Tube

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Journal of Thermal Science 2014年第6期23卷 544-551页

作者： Tae-Hyun Chang Hae-Soo Lee Keon-Je Oh Doeg Hee Doh Chang-Hoan Lee Senior Research fellow of RESEAT Korea Institute of Science and Information postdoctoral Research fellow School of Mechanical Engineering of Kyungnam University School of Mechanical Engineering Kyungnam University Division of Mechanical and Energy Systems Engineering Korea Marine and Ocean University Korea Institute of Science and Technology Information

The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted *** baffles are also an important element inside the heat *** materials influence the flow pattern in the *** influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular *** velocity of the particles was measured before the baffle and between them in the test *** show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front *** flows circulate in the front and rear *** flow profiles are related to the Reynolds number(Re) or the flow *** velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front *** flow was employed in this study,which was produced using tangential velocities at the *** the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without ***,velocities between two baffles are not much different from those without swirl.

关键词： Baffle Shell and tube Tangential inlet Swirl Particle image velocimetry

Predictability of sediment transport in the Yellow River using selected transport formulas

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International Journal of Sediment Research 2008年第4期23卷 283-298页

作者： D.S.van MAREN postdoctoral fellow Delft University of Technology Faculty of Civil Engineering and Geosciences the Netherlands and WL | Delft HydraulicsPO Box 177 2600 MH Delft The Netherlands.

This paper evaluates the applicability of the sediment transport methods developed by Engelund and Hansen, Ackers and White, Yang et al., and van Rijn, together with the Wuhan methods developed in China, to the Yellow River, which has highly concentrated and fine-grained sediment. The sediment data includes over 1000 observations from the Yellow River, 32 sets of data from a canal, and 266 sets of data from laboratory flumes. The best predictions were obtained by the Yang 1996 method, the Wuhan method, and the modified Wuhan method by Wu and Long, while reasonably good predictions were also provided by the van Rijn 2004 method. The Engelund and Hansen, the Ackers and White, and the van Rijn 1984 methods in their original forms are not applicable to the Yellow River. The predicted results for total load concentrations were as good as for bed-material concentrations, even though the total load includes a large portion of wash load.

关键词： Yellow River Sediment transport High concentration Fine sediment

DISCIPLINED APPROACHES FOR CONSTRUCTING A RULE OF LAW ORDER： RECONSIDERATIONS REVISED SOCIAL MOVEMENT AND CONSTITUTIONAL CHANGE： THE CASE OF THE UNITED STATES

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Frontiers of Law in China-Selected Publications from Chinese Universities 2016年第4期11卷 592-615页

作者： YAN Tian J.S.D. Yale Law School postdoctoral fellow Peking University Law School Beijing 100871 China

The major challenge that the theory of constitutional change in contemporary United States faced is social movement, and its core concern is to balance and maintain legal and political authorities of the Constitution through interpretation. At the descriptive level, the thoughts of liberal scholars of constitutional law who criticized the theory of originalism restored the true colors of social movement in acting on judicial interpretation of the Constitution in individual cases, thus summarized the rules of occurrence of such action, and put forward the theory of constitutional culture of the mechanism of action and that of the three-stages of action. At the prescriptive level, social movement is burdened with the ＂original sin＂ of political factions, and contrasted with the principle of republicanism in the constitutional era. During the Cold War period, pluralist theory linked social movement with the value of democracy, and began to accept its constitutional status. Moreover, given that the influence of social movement on judicial interpretation must be restricted in order to harmonize the conflict between political and legal authorities of the Constitution, both the pluralists and republicans put forward different schemes in response.

关键词： social movement authority of the constitution constitutional change pluralisttheory republicanism

Real Estate Tax Reform,Economic Growth and Financial Stability

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China Finance and Economic Review 2022年第1期11卷 89-112页

作者： Chuang Zhou Min Pan School of Finance Jiangxi University of Finance and EconomicsPostdoctoral Fellow of Jiangxi University of Finance and Economics College of Finance and Statistics Hunan University

By constructing a multi-sector DSGE model embedded with tax wedge, housing mortgage fi nancing constraints and bank supervision constraints, this paper investigates the long-term impact of two types of real estate tax policies on economic growth and fi nancial stability, which are the unifi ed tax base assessment ratio and differential tax base assessment ratio for two major housing owners (household and enterprises). It also compares and analyzes the short-term impact of the above two types of real estate tax reform schemes on economic fl uctuations and fi nancial risks under the background of potential fi nancial risks facing China’s economy. The results show that: in the long run, the real estate tax will help economic growth, boost household consumption, and effectively suppress the excessive increase in household leverage and asset bubble risk through the “suppression effect” of housing prices and the “redistribution effect” on housing. In the short run, the real estate tax will not intensify the impact of systemic fi nancial risks, so it will not have an adverse impact on the maintenance of fi nancial stability. Different real estate tax policies have different impact on economic growth and fi nancial stability. Compared with the real estate tax with unifi ed tax base assessment ratio, the real estate tax with differential tax base assessment ratio is better for the coordinated development of financial activities and the real economy in the long term and play a stronger role in economic growth, which contributes to the unity of “stable growth”, “risk prevention” and “reform”.

关键词： real estate tax economic growth fi nancial stability DSGE