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Immortal solution of the Ricci flow

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science china mathematics 2005年第z1期48卷 217-224页

作者： RUAN Qihua & CHEN Zhihua Department of Applied mathematics, Tongji university, shanghai 200092, china Department of mathematics, Putian college, Putian 351100, china Tongji Univ Dept Appl Math Shanghai 200092 Peoples R China Putian Coll Dept Math Putian 351100 Peoples R China

For any complete noncompact Kahler manifold with nonnegative and bounded holomorphic bisectional curvature, we provide the necessary and sufficient condition for the immortal solution to the Ricci flow.

关键词： Ricci flow, immortal solution, holomorphic bisectional curvature.

SIMULATION OF THE OIL SLICK MOVEMENT IN TIDAL WATER-WAYS

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Journal of Hydrodynamics 2010年第1期22卷 96-102页

作者： WUZhao-chun WANG Dao-zeng shanghai Institute of Applied mathematics and Mechanics Shanghai University Shanghai 200072 China School of Construction and Safety Engineering Shanghai Institute of Technology Shanghai 200235 China

Based on particle approach and tidal flow model this article studies the behavior of the oil slick on the water surface in the Huangpu River, a tidal waterway in shanghai. In order to track the oil slick motion, a two-dimensional oil trajectory model is used. The dynamical properties of spilled oil characterized by advection, oil spreading and turbulent diffusion are considered in the model. The simulation results consistent with the flume experimental data show that the model is applicable. Both simulation and experiment illustrate that the tidal flow has a great influence on the oil slick motion. The calculated results can be used as a reference for the response to oil spill accidents in rivers.

关键词： particle approach track of oil slick numerical simulation

ON THE LAPLACIAN SPECTRAL RADII OF TREES WITH NEARLY PERFECT MATCHINGS

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Journal of Systems science & Complexity 2009年第3期22卷 533-540页

作者： Li ZHANG Jiayu SHAO Department of Applied mathematics Shanghai Finance University Shanghai 201209 China. Department of mathematics Tongji University Shanghai 200092 China.

Let ：T2k＋1 be the set of trees on 2k＋ 1 vertices with nearly perfect matchings, and let S2k＋2 be the set of trees on 2k ＋ 2 vertices with perfect matchings. The largest Laplacian spectral radii of trees in ：T2k＋l and S2k＋2 and the corresponding trees were given by Guo （2003）. In this paper, the authors determine the second to the sixth largest Laplacian spectral radii among all trees in T2k＋1 and give the corresponding trees.

关键词： Tree Laplacian eigenvalue nearly perfect matching perfect matching.

A MULTIYEAR LAGS INPUT-HOLDING-OUTPUT MODEL ON EDUCATION WITH EXCLUDING IDLE CAPITAL

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Journal of Systems science & Complexity 2009年第2期22卷 159-170页

作者： Xue FU Xikang CHEN shanghai normal university Shanghai 200234 China. Email: foo_xue@***. Academy of mathematics and Systems science Chinese Academy of Sciences Beijing 100190 China.

This paper develops a multi-year lag Input-Holding-Output （I-H-O） Model on education with exclusion of the idle capital to address the reasonable education structure in support of a sustainable development strategy in china. First, the model considers the multiyear lag of human capital because the lag time of human capital is even longer and more important than that of fixed capital. Second, it considers the idle capital resulting from the output decline in education, for example, student decrease in primary school. The new generalized Leonitief dynamic inverse is deduced to obtain a positive solution on education when output declines as well as expands. After compiling the 2000 I-H-O table on education, the authors adopt modifications-by-step method to treat nonlinear coefficients, and calculate education scale, the requirement of human 2020. It is found that structural imbalance of human development. capital, and education expenditure from 2005 to capital is a serious problem for Chinese economic

关键词： Education human capital idle capital Input-Holding-Output model multi-year lag.

CONVERGENCE PROPERTIES OF PROJECTED GRADIENT METHODS WITH NONMONOTONIC BACK TRACKING TECHNIQUE FOR CONVEX CONSTRAINED OPTIMIZATION

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Systems science and Mathematical sciences 2000年第4期13卷 407-424页

作者： ZHU Detong (Department of mathematics, shanghai normal university, shanghai 2.02.4, china) 上海师范大学数学系上海 200234

This paper proposes projected gradient algorithms in association with using both trust region and line search techniques for convex constrained optimization problems. The mixed strategy is adopted which switches to back tracking steps when a trial projected gradient step produced by the trust region subproblem is unacceptable. A nonmonotone criterion is used to speed up the convergence progress in some curves with large curvature. A theoretical analysis is given which proves that the proposed algorithms are globally convergent and have local superlinear convergence rate under some reasonable conditions. The results of numerical experiments are reported to show the effectiveness of the proposed algorithms.

关键词： Line search trust region projected gradient nonmonotone technique convex constrained optimization.

Some New Approaches to Duffing Equation with Strongly and High Order Nonlinearity (II) Parametrized Perturbation Technique

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Communications in Nonlinear science and Numerical Simulation 1999年第1期4卷 78-83页

作者： Jihuan HE (shanghai institute of Applied mathematics and Mechanics, shanghai university, shanghai 200072, china) Email: glliu@*** shanghai Institute of Applied mathematics and Mechanics Shanghai University Shanghai 200072 China

For the strongly nonlinear equations without small parameter, a transformation u = v can be introduced for the nonlinear equation L(u) + N(u) = 0, where L and N are general linear and nonlinear differential operators respectively, P is sufficiently small. Therefore, a strongly non-linear system is transformed into a small parameter system with respect to the new introduced parameter P, thus various traditional perturbation techniques can be applied. By Lindstedt-Poincare method, a perturbation solution for Duffing equation with sib order nonlinearity is obtained, which is valid not only for the small parameter E in the equation, but also for very large values of E.

关键词： perturbation technique nonlinear equation

SIMULATION OF NON-POINT POLLUTANTS EVOLUTION IN COASTAL PLAIN ISLAND-A CASE STUDY OF CHONGMING ISLAND

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Journal of Hydrodynamics 2008年第2期20卷 246-253页

作者： YIN Hai-long JIANG Wen-yan LI Jian-hua college of Environmental science and Engineering Tongji University Shanghai 200092 China Department of Environmental science East China Normal University Shanghai 200063 China

The coastal plain region usually shows the agricultural dominated industry mode, so more and more attention is paid to non-point pollutants discharge. In this study, the method for assessing the influence of non-point pollutants discharge on river water quality is probed which is concluded as follows：（1） Considering the costal plain island is characterized as nearly even elevation, the conventional gravitational runoff confluence method based on eight-point gravitational flowing directions （DS） is unable to compute the runoff confluence received by the surrounding rivers, so a new method of triangular confluence based on three-points of grid center and the river segments is presented. Further the equations of non-point pollutants loads estimation and non-point pollutants confluence on rivers are presented. （2） The integration mode of non-point pollutants model and river water quality model is presented so as to further assess the non-point pollutants contribution to river water quality. （3） With the Chongming Island, the third largest island in china, as an example, the above-mentioned equations are specified. For this island, the non-point pollutants loads are estimated and linked to the developed water quality model of the river network in the island, and further the non-point pollution evolution in river network is simulated. In this scenario, the non-point pollution contribution to river water quality over the whole island is clearly displayed, and the area where the river water quality is seriously influenced by non-point pollutants discharge is distinctly depicted. This scenario also shows the water quality contribution ratio of non-point pollution to point pollution can be in the range of 55.5% to 44.5% which proves the importance of non-point pollution control in costal plain islands.

关键词： non-point pollution runoffconfluence water quality model Chongming Island

A New Approach to Nonlinear Partial Differential Equations

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Communications in Nonlinear science and Numerical Simulation 1997年第4期2卷 230-235页

作者： Jihuan HE (shanghai university,shanghai Institute of Applied mathematics and Mechanics,shanghai 2 0 0 0 72 ,china) shanghai university Shanghai Institute of Applied Mathematics and Mechanics Shanghai 200072 China

In this paper,a novel method called variational iteration method is proposed to solve nonlinear partial differential equations without linearization or small *** this method,a correction functional is constructed by a general Lagrange multiplier,which can be identified via variational *** analytical solution can be obtained from its trial- function with possible unknown constants,which can be identified by imposing the boundary conditions,by successively iteration.

关键词： Nonlinear Problems Partial Differential Equations Variational Iteration Method Variational Theory

Experimental Study of Energy-Saving Air-Conditioner with Hot Water

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湖南大学学报（自然科学版） 2009年第S1期36卷 75-78页

作者： CHEN Jian-bo,CHEN Dan,LU Ying(university of shanghai for science and Technology,shanghai,china) university of shanghai for science and Technology Shanghai 200000 China

Energy-saving air-conditioner with hot water is an air source heat pump air-conditioner,which can also supply hot *** hot water is heated by a double pipe condenser connected with an air-cooled condenser in series in the *** experiment of the energy-saving air-conditioner was carried out in the enthalpy-difference air-conditioner *** hot water temperature and the compressor's discharge and suction pressure were recorded in the working condition,where the ambient temperature was at 43 ℃,35 ℃,21 ℃,7 ℃,and 2 ℃ *** results showed that the system operated stably and *** system can supply 240 L hot water at 50 ℃ in the whole year,and its coefficience of performance(COP)is much higher than the conventional air source heat pump *** energy conservation was proved by comparing the thermal efficiency with other sourece water heaters.

关键词： air-conditioning water heaters energy conservation heat pump systems thermal efficiency