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Parameterized expressions for an improved Rouse equation

International Journal of Sediment Research 2013年第4期28卷 523-534页

作者： Chen CHENG Zhi-yao SONG Yi-gang WANG Jin-shan ZHANG School of Marine Sciences Nanjing University of Information Science&Technology Key Laboratory of Virtual Geographic Environment under Ministry of Education and Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex SystemNanjing Normal University College of Harbor Coastal and Offshore EngineeringHohai University River Harbor Engineering Department Nanjing Hydraulic Research Institute

The equilibrium profile of suspended sediment concentration（SSC） in steady,uniform turbulent flow has been extensively studied since the proposition of Rouse equation（Rouse,1937）.Many researchers keep studying and attempting to improve the Rouse equation by modifying the mixing length *** and Dey（2009） improved Rouse equation based on the modified sediment diffusivity,however,their proposed sediment diffusivity has two parameters,the depth modification factor α and the reciprocal of the sediment Schmidt number β=1/S;,and the corresponding expressions were not given properly in their *** paper aims to parameterize the relevant coefficients,the results shows:（1）α is parameterized from a reasonable approximation by the analysis of surface boundary condition of SSC;（2） considering some effect factors on the settling velocity,β can be expressed by an extended and modified Montcs-Ippen formula,and its related parameters are calibrated by substantial data about the relationship between the primary Rouse parameter Z.= ω;/*** its counterpart Z.’=ω;/β*** verification with some experimental and field datasets,and comparison with related formula,the results show that the sediment diffusivity and SSC profiles have a good agreement with measured data used the present parameterized expressions of a and β,so the present improved Rouse equation is reasonable,and can be applied in practical ***,an approximation and simplified expression of the improved Rouse equation is deduced by using the approach of perturbation,which can be applied easily for the estimation of suspended sediment transport rate.

关键词： Improved Rouse equation Parameterization Sediment transport

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B¯s0→(π0η(′),η(′)η(′)) decays and the effects of next-to-leading order contributions in the perturbative QCD approach

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Physical Review D 2014年第11期90卷 114028-114028页

作者： Zhen-Jun Xiao Ya Li Dong-Ting Lin Ying-Ying Fan Ai-Jun Ma Department of Physics and Institute of Theoretical Physics Nanjing Normal University NanjingJiangsu 210023 People’s Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China College of Physics and Electronic Engineering Xinyang Normal University Xinyang Henan 464000 People’s Republic of China

In this paper, we calculate the branching ratios and CP-violating asymmetries of the five B¯s0→(π0η(′),η(′)η(′)) decays, by employing the perturbative QCD (pQCD) factorization approach and with the inclusion of all currently known next-to-leading order (NLO) contributions. We find that (a) the NLO contributions can provide about 100% enhancements to the LO pQCD predictions for the decay rates of B¯s0→ηη′ and η′η′ decays, but result in small changes to Br(B¯s→π0η(′)) and Br(B¯s→ηη); (b) the newly known NLO twist-2 and twist-3 contributions to the relevant form factors can provide about 10% enhancements to the decay rates of the considered decays; (c) for B¯s→π0η(′) decays, their direct CP-violating asymmetries Afdir could be enhanced significantly by the inclusion of the NLO contributions; and (d) the pQCD predictions for Br(B¯s→ηη(′)) and Br(B¯s→η′η′) can be as large as 4×10−5, which may be measurable at LHCb or the forthcoming Super-B experiments.

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Generation of orthogonal curvilinear grids on the sphere surface based on Laplace-Beltrami equations

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IOP Conference Series: Earth and Environmental Science 2014年第1期19卷

作者： Fuqiang Lu Zhiyao Song Xin Fang Key Laboratory of Virtual Geographic Environment (Ministry of Education) Nanjing Normal UniversityNanjing Jiangsu Province 210046 China AA(Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical Sciences Nanjing Normal University Nanjing 210046 China

In this paper, Laplace-Beltrami equations are used to generate orthogonal curvilinear grids on the sphere for ocean models. In addition to overcoming the pole-problem, the grid configuration has quasi-uniform cell-size on the whole sphere. Some quantities such as the grid length along two directions, the angle deviation from orthogonality, the area of the cell to evaluate the quality of the grid, which demonstrate the grid produced is fit to be a model grid on which the finite difference method or finite volume method can be implemented for numerical simulating of global atmosphere and ocean dynamics on large scale.

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Clifford algebra-based spatio-temporal modelling and analysis for complex geo-simulation data

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AIP Conference Proceedings 2013年第1期1558卷 542-545页

作者： Wen Luo Zhaoyuan Yu Yong Hu Linwang Yuan Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University No.1 Wenyuan Road Nanjing China Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University No.1 Wenyuan Road Nanjing China and Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal Univer China

The spatio-temporal data simulating Ice-Land-Ocean interaction of Antarctic are used to demonstrate the Clifford algebra-based data model construction, spatio-temporal query and data analysis. The results suggest that Clifford algebra provides a powerful mathematical tool for the whole modelling and analysis chains for complex geo-simulation data. It can also help implement spatio-temporal analysis algorithms more clearly and simply.

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A Modification to Vertical Distribution of Tidal Flow Reynolds Stress in Shallow Sea

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China Ocean Engineering 2012年第3期26卷 431-442页

作者：倪志辉宋志尧张绪进吴立春易静 Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education and National Engineering Research Center for Inland Waterway RegulationChongqing Jiaotong University Southwestern Research Institute of Water Transportation Engineering Chongqing Jiaotong University Key Lab of Virtual Geographic Environment under Ministry of Education and Jiangsu Key Lab for Numerical Simulation of Large-Scale Complex SystemNanjing Normal University Chongqing University of Education

Tidal flow is a periodic movement of unsteady and non-uniform, which has acceleration and deceleration process obviously, especially in coastal shallow waters. Many researches show that vertical distribution of tidal flow Reynolds stress deviated from linear distribution. The parabolic distribution of the tidal flow Reynolds stress was proposed by Song et al. （2009）. Although the model fills better with field observations and indoor experimental data, it has the lower truncated series expansion of tidal flow Reynolds stress, and the description of the distribution is not very comprehensive By introducing the motion equation of tidal flow and improving the parabolic distribution established by Song et al. （2009）, the cubic distribution of the tidal flow Reynolds stress is proposed. The cubic distribution is verified well by field data （Bowden and Fairbairn, 1952; Bowden et al., 1959; Rippeth et al., 2002） and experimental data （Anwar and Atkins, 1980）, is consistent with the numerical model results of Kuo et al. （1996）, and is compared with the parabolic distribution of the tidal flow Reynolds stress. It is shown that this cubic distribution is not only better than the parabolic distribution, but also can better reflect the basic features of Reynolds stress deviating from linear distribution downward with the tidal flow acceleration and upward with the tidal flow deceleration, for the foundation of further study on the velocity profile of tidal flow.

关键词： tidal flow Reynolds stress linear distribution parabolic distribution cubic distribution

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On the Coupled of NBEM and FEM for an Anisotropic Quasilinear Problem in Elongated Domains

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American Journal of Computational Mathematics 2012年第2期2卷 143-155页

作者： Baoqing Liu Qikui Du Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing China School of Mathematical Science Nanjing Normal University Nanjing China

In this paper, based on the Kirchhoff transformation, the coupling of natural boundary element method and finite element method are discussed for solving exterior anisotropic quasilinear problems with elliptic artificial boundary. By the principle of the natural boundary reduction, we obtain natural integral equation on elliptic artificial boundaries, the coupled variational problem and its numerical method. Moreover, the convergence and error estimate of the approximate solutions are obtained. Finally, some numerical examples are presented to illuminate the feasibility of the method.

关键词： Quasilinear Elliptic Equation Elliptic Artificial Boundary Natural Integral Equation

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STABILITY OF SVIR system WITH RANDOM PERTURBATIONS

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International Journal of Biomathematics 2012年第4期5卷 97-111页

作者： CHAO DENG HONGJUN GAO Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical Sciences Nanjing Normal University Nanjing 210046 P. R. China

In this paper, the SVIR epidemic models with continuous vaccination strategies investi- gated by Liu, Takeuchi and Iwamo, [SVIR epidemic models with vaccination strategies, J. Theor. Biol. 253 （2008） 1 11], allowing random fluctuation around the endemic equi- librium and the transmission rate t3 are analyzed. The equilibrium state of the model with random perturbation is locally asymptotically stable as shown by a Lyapunov stability analysis.

关键词： Local asymptotic stability SVIR model Lyapunov function white noise.

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A New Analytical Solution for Tide-Induced Groundwater Fluctuations in An Unconfined Aquifer with A Sloping Beach

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China Ocean Engineering 2011年第3期25卷 479-494页

作者：孔俊宋志尧辛沛沈城吉 College of Harbor Coastal and Offshore Engineering Hohai University Key Laboratory of Virtual Geographic Environment under Ministry of Education and Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex SystemNanjing Normal University National Centre for Groundwater Research and Training The University of Queensland

Deriving analytical solutions for tide-induced groundwater fluctuations in unconfined aquifers confronts two problems：（1） As the Boussinesq equation itself contains nonlinear terms, the ＂secular term＂ would be generated in derivation, thus making perturbation solution unable to be deduced to higher order; （2） for aquifers with sloping beaches, the perturbation parameter in existing analytical solution integrating the beach slope and hydrogeological property would be sometimes larger than 1. So the application of perturbation solutions is relatively limited. Furthermore, as the beach slope decreases, the error of analytical solution would gradually increase. Given that water table over-height would increase the aquifer thickness and speed up wave propagation, this paper integrates over-height into the perturbation parameter and adjusts boundary conditions to settle the problem of ＂secular term＂ and to derive a new high-order analytical solution for nonlinear Boussinesq equation in terms of sloping beaches. Results show that the new analytical solution is more reasonable, and the analytical accuracy is obviously improved in comparison with the existing analytical solution for a gentle slope. The new analytical solution provides a theoretical basis for analyzing the propagation characteristics （e.g., wave length and over-height variation） of tide-induced groundwater wave in unconfined aquifers, particularly those with sloping beaches.

关键词： tide groundwater analytical solution over-height perturbation method

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Erratum: Chiral phase and quantum phase transitions of anisotropic XY chains with three-site interactions

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Journal of Statistical Mechanics: Theory and Experiment 2012年第11期2012卷

作者： Xiaoxian Liu Ming Zhong Hui Xu Peiqing Tong Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210046 People's Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210046 People's Republic of China

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Heat conduction in one-dimensional aperiodic quantum Ising chains

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Physical Review E 2011年第3期83卷 031128-031128页

作者： Wenjuan Li Peiqing Tong Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210046 People’s Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210046 People’s Republic of China

The heat conductivity of nonperiodic quantum Ising chains whose ends are connected with heat baths at different temperatures are studied numerically by solving the Lindblad master equation. The chains are subjected to a uniform transverse field h, while the exchange coupling Jm between the nearest-neighbor spins takes the two values JA and JB arranged in Fibonacci, generalized Fibonacci, Thue-Morse, and period-doubling sequences. We calculate the energy-density profile and energy current of the resulting nonequilibrium steady states to study the heat-conducting behavior of finite but large systems. Although these nonperiodic quantum Ising chains are integrable, it is clearly found that energy gradients exist in all chains and the energy currents appear to scale as the system size 〈Q〉~Nα. By increasing the ratio of couplings, the exponent α can be modulated from α>−1 to α<−1 corresponding to the nontrivial transition from the abnormal heat transport to the heat insulator. The influences of the temperature gradient and the magnetic field to heat conduction have also been discussed.

关键词： HEAT conduction ISING model EQUATIONS FIBONACCI sequence THERMAL conductivity

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