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Insight into herbicide resistance of W574L mutant Arabidopsis thaliana acetohydroxyacid synthase:molecular dynamics simulations and binding free energy calculations

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Science china Chemistry 2010年第1期53卷 91-102页

作者： YU ZhiHong,WEN Xin & XI Zhen State Key Laboratory of Elemento-Organic Chemistry department of Chemical Biology,Nankai university,Tianjin 300071,china State Key Laboratory of Elemento-Organic Chemistry department of Chemical Biology Nankai University Tianjin China

Acetohydroxyacid synthase(AHAS) is the target enzyme of several classes of herbicides,such as sulfonylureas and *** many mutant AHASs with herbicide resistance have emerged along with extensive use of herbicides,therefore it is imperative to understand the detailed interaction mechanism and resistance mechanism so as to develop new potent inhibitors for wild-type or resistant *** the aid of available crystal structures of the Arabidopsis thaliana(At) AHAS-inhibitor complex,molecular dynamics(MD) simulations were used to investigate the interaction and resistance mechanism directly and dynamically at the atomic ***-level MD simulations were performed on six systems consisting of wild-type or W574L mutant AtAHAS in the complex with three sulfonylurea inhibitors,separately,and binding free energy was calculated for each system using the MM-GBSA *** analyses from structural and energetic aspects confirmed the importance of residue W574,and also indicated that W574L mutation might alert the structural charactersistic of the substrate access channel and decrease the binding affinity of inhibitors,which cooperatively weaken the effective channel-blocked effect and finally result in weaker inhibitory effect of inhibitor and corresponding herbicide resistance of W574L *** our knowledge,it is the first report about MD simulations study on the AHAS-related system,which will pave the way to study the interactions between herbicides and wild-type or mutant AHAS dynamically,and decipher the resistance mechanism at the atomic level for better designing new potent anti-resistance herbicides.

关键词： sulfonylurea herbicides,acetohydroxyacid synthase,W574L mutant,herbicide resistance,molecular dynamics simulations,binding free energy calculation MM-GBSA

SIMULATION OF FLUID-SOLID INTERACTION ON WATER DITCHING OF AN AIRPLANE BY ALE METHOD

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Journal of Hydrodynamics 2011年第5期23卷 637-642页

作者： HUA Cheng FANG Chao CHENG Jin department of Mechanics and Engineering Science Fudan University Shanghai 200433 China School of Mathematical Sciences Fudan University Shanghai 200433 China

Ditching is considered as one of the important aspects of safety performances of airplanes. It is related primarily with the fluid-solid interaction, whose studies mainly depend on experiments at the present time. Numerical and analytical methods for fluid-solid interaction by using 3-D full scale airplane＇s model will reduce the dependence on the expensive model tests. Numerical studies can be used to estimate the safety of ditching and provide a reference for the crashworthiness design. This article proposes a 3-D dynamical structural model after the real shape of an airplane and an Arbitrary Lagrange-Euler （ALE） fluid-field model, to simulate the fluid-solid interactions caused by low speed ditching. The simulation is based on interaction computational methods, within LS-DYNA nonlinear finite-element code. The results of pressure distributions and accelerating time histories of the airplane＇s subfloor are discussed in the context of the safety of ditching, and the simulation results and the analytical methods are verified.

关键词： ditching fluid structure interaction Arbitrary Lagrange-Euler (ALE) finite element method

Solving A Kind of High Complexity Multi-Objective Problems by A Fast Algorithm

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Wuhan university Journal of Natural Sciences 2003年第S1期8卷 183-188页

作者： Zeng San-you, Ding Li-xin, Kang Li-shandepartment of Computer Science,china university of GeoSciences, Wuhan 430074, Hubei, china department of Computer Science, Zhuzhou Institute of Technology , Zhuzhou 412008, Hunan, china State Key Laboratory of Software Engineering, Wuhan university, Wuhan 430072, Hubei, china department of Computer Science China University of GeoSciences Wuhan Hubei China department of Computer Science Zhuzhou Institute of Technology Zhuzhou Hunan China State Key Laboratory of Software Engineering Wuhan University Wuhan Hubei China

A fast algorithm is proposed to solve a kind of high complexity multi-objective problems in this paper. It takes advantages of both the orthogonal design method to search evenly, and the statistical optimal method to speed up the computation. It is very suitable for solving high complexity problems, and quickly yields solutions which converge to the Pareto-optimal set with high precision and uniform distribution. Some complicated multi-objective problems are solved by the algorithm and the results show that the algorithm is not only fast but also superior to other MOGAS and MOEAs, such as the currently efficient algorithm SPEA, in terms of the precision, quantity and distribution of solutions.

关键词： evolutionary algorithms orthogonal design multi-objective optimization Pareto-optimal set

Infinite Three-Dimensional Coordination Polymers: Synthesis and Structures of [Cd (4,4'-bpy)_2 (H_2O)_2]_n (pic)_(2n),[Zn (4,4'-bpy)_2 (H_2O)_2]_n(pic)_(2n) (H_2O)_(2n), and [Zn (4,4'-bpy)_2 (H_2O)_2]_n (4,4'-bpy)_n(H_2O)_n (pic)_(2n)

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Chinese Chemical Letters 2000年第4期11卷 369-372页

作者： Fu Pei LIANG~1 Zi Lu CHEN~1 Rui Xiang HU~1 Hong LIANG~1 Zhao Hui ZHOU~2 (1 department of Chemistry. Guangxi normal university: Guilin 541004 2 department of Chemistry. Xiamen university. Xiamen 361005) department of Chemistry Guangxi Normal University Guilin 541004 China department of Chemistry Xiamen University Xiamen 361005 China

Three Complexes of the formula [Cd (4,4'-bpy)_2 (H_2O)_2]_n. (pic)_(2n) (1) [Zn (4,4'-bpy)_2 (H_2O)]_n (4,4'-bpy)_n(H_2O)_n (pic)-(2n) (2) and [Zn (4,4'-bpy)_2 (H_2O)]_n (4,4'-bpy)_n (pic)-(2n)(H_2O)_n (3) (4.4'-bpy = 4.4'-bipyridine. pic = picric anion ) have been synthesized and characterized by elemental analysis and single-crystal x-ray diffraction. They all have infinite three-dimensional network structure. crystallizing in the monoclinic space group C2/c (1) and Cc (2.3).

关键词： Clathration. 4. 4' - bipyridine. picric anion. three - dimensional network.

Transient Responses of Flexible Non-uniform Spinning Shaft with Nonlinear and Asymmetric Supports

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Journal of Shanghai university(English Edition) 2001年第1期5卷 35-39页

作者： ZHU Huai liang department of Mechanics, College of Sciences, Shanghai university, Shanghai 200436, china department of Mechanics College of Sciences Shanghai University Shanghai China

In this paper, a hybrid approach was developed to investigate the transient responses of a multi span non uniform flexible spinning shaft with nonlinear and asymmetric supports. The non uniform spinning shaft with variable parameters was modeled as a Bernoulli Euler beam column with sectional constant cross section properties by the finite element method. The supporting stiffness behavior of the nonlinear supports was described as a piecewise linear and asymmetric model. The equations of motion in the matrix form of a multi span non uniform spinning shaft with nonlinear and asymmetric supports were formulated using Hamilton's principle and the assumed mode method. As an example, a spinning rocket with many variable stiffness supports was numerically simulated by the direct integration method. The transient response and dynamic behavior of this rotate dynamic system are analyzed.

关键词： spinning shaft nonlinear support asymmetric support dynamics transient response

Research on the Circulation Problems of Contractual Management Right of Rural Land

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Asian Agricultural Research 2010年第12期2卷 52-55,60页

作者： CHEN Han-bing Politics and Law department of Zhoukou normal university, Zhoukou 466001, china

Based on the judicial explanation of the contractual management right of land, the thesis elaborates the definition of main body of contractual management right of rural land; right of possession, use right, usufruct of contractual management right of land; autonomy of production and operation; disposition of the products; expropriation and occupation compensation authority of contractual land respectively, in order to demonstrate the connotation of land contractual management. The thesis also analyzes perspicaciously the phenomenon of non-agricultural-use land and proclaiming phenomenon of contractual management right of land. We should establish normalized rural land property rights register system to perfect contractual management right of land. Proclaiming of agriculture land right also should adopt registration effectiveness so as to guarantee the legality of transference of agricultural land to non-agricultural land in terms of system. We should perfect rural land circulation in terms of normalizing land circulation laws and normalizing contractual farmers fees: in terms of the movable agricultural land right, we should further perfect the types and content of circulation and lessen non-legal form restrictions of circulation; in terms of contractual fees, we should normalize contractual fees of land in order to preclude the contradiction between the contractees and contractors arising from blank space of laws.

关键词： Rural land Contractual management right Circulatio

Water demand for ecosystem protection in rivers with hyper-concentrated sediment-laden flow

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Science china(Technological Sciences) 2004年第Z1期47卷 186-198页

作者： LUO Huaming, LI Tianhong, NI Jinren & WANG Yudong department of Environmental Engineering, Peking university, Beijing 100871, china The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, china department of Environmental Engineering Peking University Beijing China The Key Laboratory of Water and Sediment Sciences Ministry of Education Beijing China

Sediment transport is one of the main concerns in a river system with hyper-concentrated flows. Therefore, the water use for sediment transport must be considered in study on the water demand for river ecosystem. The conventional methods for calculating the Minimum Water Demand for River Ecosystem (MWDRE) are not appropriate for rivers with high sediment concentration. This paper studied the MWDRE in wet season, dry season and the whole year under different water-and-sediment conditions in the Lower Yellow River, which is regarded as a typical river with sediment-laden flows. The characteristics of MWDRE in the river are analyzed. Firstly, the water demand for sediment transport (WDST) is much larger than the demands for other riverine functions, the WDST accounts for the absolute majority of the MWDRE. Secondly, in wet season when the WDST is satisfied, not only most of the annual incoming sediment can be transported downstream, but also the water demands for other river functions can be satisfied automatically, so that the MWDRE in wet season is identical to the WDST. Thirdly, in dry season, when the WDST is satisfied, the water demands for other river functions can also be satisfied, but the low sediment transport efficiency results in significant waste of water resources. According to these characteristics and aiming at decreasing sediment deposition in the riverbed and improving the utilization efficiency of water resources, hydrological engineering works can be used to regulate or control flow and sediment so that the sediment incoming in dry season can be accumulated and be transported downstream intensively and thus efficiently in wet season.

关键词： sediment-laden flow, the Lower Yellow River, water demand for river ecosystem, water demand for sediment transport

Some basic principles for the linear theory of piezoelectric micropolar elastodynamics

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中国科学：物理学、力学、天文学英文版 2010年第6期53卷 1094-1100页

作者： LUO En & LI WeiHua department of Applied Mechanics and Engineering,Sun Yat-sen university,Guangzhou 510275,china department of Applied Mechanics and Engineering Sun Yat-sen University Guangzhou China

According to the basic idea of classical yin-yang complementarity and modern dual-complementarity,in a simple and unified way proposed by Luo,some basic principles in the linear theory of piezoelectric micropolar elastodynamics can be established systematically. In this paper,an important integral relation in terms of convolutions is given,which can be considered as the generalized principle of virtual work in mechanics. Based on this relation,it is not only possible to obtain the principle of virtual work and the reciprocal theorem,but also to systematically derive the complementary functionals for the eleven-field,nine-field and six-field simplified Gurtin-type variational principles and the potential energy-functional for the three-field one in the linear theory of piezoelectric micropolar elastodynamics by the generalized Legendre transformations given in this paper. Furthermore,with this approach,the intrinsic relationships among various principles can be explained clearly.

关键词： piezoelectric micropolar elastodynamics principle of virtual work reciprocal theorem simplified Gurtin-type variational principle complementary relation

A STOCHASTIC GROWTH MODEL WITH ENVIRONMENTAL POLLUTION

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Journal of Systems Science & Complexity 2006年第3期19卷 414-422页

作者： Xueqing ZHANG Shigeng HU Haijun WANG department of mathematics Huazhong University of Science and Technology Wuhan 430074 China.

Pollution is introduced into the utility function and the productive function in this *** appropriate macroeconomic equilibrium conditions, this paper proves that the equilibrium levels of the main economic indexes are uniquely determined by the model parameters. This paper establishes the following alternative theorem： some factors affect the economic growth and the welfare in opposite way.

关键词： Bellman equation environmental protection stochastic growth stochastic optimization.