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Convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations

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Science China Mathematics 2006年第2期49卷 255-266页

作者： XIAO Ling, LI Fucai & WANG Shu Academy of Mathematics and Systems Science, Chinese Academy of sciences, beijing 100080, China Department of Mathematics, Nanjing university, Nanjing 210093. China {3. of applied sciences, beijing university of technology, beijing 100022, China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Department of Mathematics Nanjing University Nanjing China college of applied sciences Beijing University of Technology Beijing China

We establish the convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations in this paper. The convergence is rigorously proved on the time interval where the smooth solution to the incompressible Euler equations exists. The proof relies on the compactness argument and the so-called relative-entropy method.

关键词： Vlasov-Poisson-Fokker-Planck system incompressible Euler equations relative-entropy method.

Analysis of China’s Water Security and Virtual Water Trade

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Chinese Journal of Population,Resources and Environment 2006年第4期4卷 18-23页

作者： Wang Hongrui1,2,Liu Xinghan3.Dong Yanyan1,2,Wang Junhong1,2 1.college of Water sciences,{3. Normal {3.,{3. 100875,China 2.Key Laboratory for Water and Sediment sciences Ministry of Education,{3. 100875,China 3.college of Economics&Management,beijing university of technology,beijing 100022,China college of Water sciences Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education Beijing 100875 China college of Economics & Management Beijing University of Technology Beijing 100022 China College of Water Sciences Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education Beijing 100875 China college of Water sciences Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education Beijing 100875 China

Producing goods and services all needs water *** water used in the process of an agricultural or industrial product is called the"Virtual Water"contained in this product. Through international trade,water-scarce countries and regions could purchase water-intensive products--especially foods,from water-rich countries to balance their water deficits and achieve water *** is one of the 13.most water-deficit countries whose water safety have been severely *** paper generalized the recent global research development and made a brief introduction about the methods calculating virtual water content in specific *** a case study,we qualified China's annual virtual water flows from year 2000 to 2002 with trade in crops,and ended with some policy advice for application and practice of virtual water strategy.

关键词： water security virtual water virtual water trade crops

Photocatalytic degradation of formaldehyde by diffuser of solar light pipe coated with nanometer titanium dioxide thin films

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Science China(Technological sciences) 2010年第1期53卷 150-154页

作者： WU YanPeng1,ZhanG WenMing1,MA ChongFang2,LU YuanWei2 & LIU Li1 1 School of Civil and Environmental Engineering,university of Science and technology {3.,{3. 100083.China 2 college of Environmental and Energy Engineering,beijing university of technology,beijing 100022,China School of Civil and Environmental Engineering University of Science and Technology Beijing Beijing China college of Environmental and Energy Engineering Beijing University of Technology Beijing China

The even and transparent nanometer TiO2 thin films named DegussaP25 as photocatalysis deposited on the surface of diffusers of solar light pipe were prepared by sol-gel *** rugged side of the diffusers of solar light pipe was coated evenly with DegussaP25 solution for the quality of 1.75 *** experiments had showed that when the coated side was away from the sun the lighting degree may be reduced compared with that facing the *** average reduction was only 3.03.,which would not have a significant impact on *** are important parts of a light pipe which can diffuse light evenly to the place needed to be *** experiments showed that in a sunny summer day under the direct sunlight,the solar light pipe combined with photocatalysis could reduce the formaldehyde volume fraction in a box of 0.1 m3.from 1.0×10-6 to 0.16×*** 1 h of photodegradation the formaldehyde volume c{3.ged from 1.0×10-6 down to 0.1×10-6 with faster and more complete degradation of *** rate of degradation under cloudy and partly cloudy conditions was slower t{3. that under sunny *** was slower in winter t{3. in summer under sunny *** experimental results also showed that the performance of photocatalysis combined with diffusers of light pipe had better effect in a small *** performance in large space,such as open space,will be the next work in the future,which will be a great challenge.

关键词： solar light pipes diffusers photocatalysis decomposition formaldehyde titanium dioxide

Study on the drug resistance and the binding mode of HIV-1 integrase with LCA inhibitor

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Science China Chemistry 2007年第5期50卷 665-674页

作者： HU JianPing1,2, ChanG Shan1, CHEN WeiZu1 & WANG CunXin1 1 college of Life Science and Bioengineering, {3., beijing 100022, China 2 Department of Chemistry & Life {3., Leshan Normal university, Leshan 614004, China college of Life Science and Bioengineering Beijing University of Technology Beijing China Department of Chemistry & Life sciences Leshan Normal University Leshan China

Human immunodeficiency virus type 1 (HIV-1) integrase (IN) is an essential enzyme in the lifecycle of this virus and also an important target for the study of anti-HIV drugs. The binding mode of the wild type IN core domain and its G140S mutant with L-Chicoric acid (LCA) inhibitor were investigated by using multiple conformation molecular docking and molecular dynamics (MD) simulation. Based on the binding modes, the drug resistance mechanism was explored for the G140S mutant of IN with LCA. The results indicate that the binding site of the G140S mutant of IN core domain with LCA is different from that of the core domain of the wild type IN, which leads to the partial loss of inhibition potency of LCA. The flexibility of the IN functional loop region and the interactions between Mg2+ ion and the three key residues (i.e., D64, D116, E152) stimulate the biological operation of IN. The drug resistance also lies in several other important effects, such as the repulsion between LCA and E152 in the G140S mutant core domain, the weakening of K159 binding with LCA and Y143.pointing to the pocket of the G140S mutant. All of the above simulation results agree well with experimental data, which provide us with some helpful information for designing the drug of anti-HIV based on the structure of IN.

关键词： molecular docking, MD simulation, HIV-1 IN, drug design

BRST quantization and canonical Ward identity of the supersymmetric electromagnetic interaction system

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Science China(Physics,Mechanics & Astronomy) 2007年第3期50卷 339-347页

作者： HUANG YongChang1,3.4, JIANG YunGuo1 & LI XinGuo2,3.1.Institute of Theoretical Physics, college of {3. {3., beijing university of technology, beijing 100022, China 2 Institute of Modern Physics, Chinese Academy of {3., Lanzhou 73.000, China 3.Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, Chinese Academy of {3., Lanzhou 73.000, China 4 China Center of Advanced Science and technology (World Laboratory), beijing 100080, China Institute of Theoretical Physics College of Applied Sciences Beijing University of Technology Beijing China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Collisions Chinese Academy of Sciences Lanzhou China China Center of Advanced Science and technology (World Laboratory) Beijing China Institute of Modern Physics Chinese Academy of Sciences Lanzhou China

According to the method of path integral quantization for the canonical constrained system in Becchi-Rouet-Stora-Tyutin scheme, the supersymmetric electromagnetic interaction system was quantized. Both the Hamiltonian of the supersymmetric electromagnetic interaction system in phase space and the quantization procedure were simplified. The BRST generator was constructed, and the BRST transforma- tions of supersymmetric fields were gotten; the effective action was calculated, and the generating functional for the Green function was achieved; also, the gauge generator was constructed, and the gauge transformation of the system was ob- tained. Finally, the Ward-Takahashi identities based on the canonical Noether theorem were calculated, and two relations between proper vertices and propaga- tors were obtained.

关键词： supersymmetric electromagnetic interaction BRST quantization Ward identity

Parameter identification theory of a complex model based on global optimization method

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & xu BingYe3.1.college of Automotive Engineering, South China {3. of {3., Guangzhou 510640, China 2 beijing Research Institute of Mechanical and Electrical {3., beijing 100083. China 3.Department of Engineering Mechanics, Tsinghua {3., beijing 100084, China college of Automotive Engineering South China University of Technology Guangzhou China beijing Research Institute of Mechanical and Electrical technology Beijing China Department of Engineering Mechanics Tsinghua University Beijing China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely {3. to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

Approximation bounds for quadratic maximization and max-cut problems with semidefinite programming relaxation

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Science China Mathematics 2007年第11期50卷 1583-1596页

作者： Da-chuan xu~(1+) Shu-zhong ZhanG~2 1 Department of applied Mathematics,{3.,beijing 100022,China 2 Department of Systems Engineering and Engineering Management,The Chinese {3. of Hong Kong,Shatin,Hong Kong,China Department of applied Mathematics Beijing University of Technology Beijing China Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong Shatin Hong Kong China

In this paper,we consider a class of quadratic maximization *** a subclass of the problems,we show that the SDP relaxation approach yields an approximation solution with the worst-case performance ratio at leastα=0.87856….In fact,the estimated worst-case performance ratio is dependent on the data of the problem withαbeing a uniform lower *** light of this new bound,we show that the actual worst-case performance ratio of the SDP relaxation approach (with the triangle inequalities added) is at leastα+δ_d if every weight is strictly positive,whereδ_d>0 is a constant depending on the problem dimension and data.

关键词： quadratic maximization max-cut problem semideflnite programming relaxation approximation algorithm performance ratio

Unsteady aerodynamic noise prediction of contra-rotating open rotor using meshless method

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Chinese Journal of Aeronautics 2024年第8期37卷 144-165页

作者： Zhiliang HONG Meng SU Haitao ZhanG Zerui xu Lin du Lingfeng CHEN college of Safety Science and Engineering Civil Aviation University of ChinaTianjin 300300China Civil Aviation Administration of China Beijing 100710China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

The Contra-Rotating Open Rotor(CROR)design confronts significant noise challenges despite being one of the possible options for future green *** efficiently estimate the noise emitted from a CROR,a three-dimensional unsteady prediction model based on the meshless method is *** unsteady wake flow and the aerodynamic load fluctuations on the blade are solved through the viscous vortex particle method,the blade element momentum theory and vortex lattice ***,the acoustic field is obtained through the Farassat’s formulation *** of this method is conducted on a CROR,and a mesh-based method,e.g.,Nonlinear Harmonic(NLH)method,is also employed for *** is found that the presented method is three times faster than NLH method while maintaining a comparable precision.A thorough parametric analysis is also carried out to illustrate the effects of rotational speed,rotor-rotor spacing and rear rotor diameter on the noise *** rotor speed is found to be the most influencing factor,and by optimizing the speed difference between the front and rear rotors,a notable noise reduction can be *** current findings not only contribute to a deeper comprehension of the CROR’s aeroacoustic properties but also offer an effective tool for engineering applications.

关键词： Contra-Rotating Open Rotor(CROR) Aerodynamic noise Blade element momentum theory Viscosity vortex particle method Farassat’s formulation 1A

Exploring binding mode for styrylquinoline HIV-1 integrase inhibitors using comparative molecular field analysis and docking studies

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Acta Pharmacologica Sinica 2004年第7期25卷 104-112页

作者： Xiao-hui MA, Xiao-yi ZhanG, Jian-jun TAN, Wei-zu CHEN, Cun-xin WANG2 college of LifeScience and Bioengineering, beijing university of technology, {3., China college of Life Science and Bioengineering Beijing University of Technology 北京 100022

AIM: To understand pharmacophore properties of styrylquinoline derivatives and to design inhibitors of HIV-1 integrase. METHODS: Comparative molecular field analysis (CoMFA) was performed to analyze three-dimen- sional quantitative structure-activity relationship (3.-QSAR) of styrylquinoline derivatives. Thirty-eight compounds were randomly divided into a training set of 28 compounds and a test set of 10 compounds. The stability of 3.- QSAR models was proved by the analysis of cross-validated and non-cross-validated methods. Moreover, the binding mode of these compounds and integrase was constructed by AutoDock program. RESULTS: The CoMFA model of the training compounds was reasonably predicted with cross-validated coefficient (q2) and conventional (r2) values (up to 0.696 and 0.754). Then the model was validated by the test set. The resulting CoMFA maps visualized structural requirements for the biological activity of these inhibitors. Docking results showed that a carboxyl group at C-7 and a hydroxyl group at C-8 in the quinoline subunit, bound closely to the divalent metal cofactor (Mg2+) around the integrase catalytic site. Moreover, there is a linear correlation between the binding energy of the inhibitors with integrase and their inhibitory effect. CONCLUSIONS: The present study indicated that the CoMFA model together with docking results could give us helpful hints for drug design as well as interpre- tation of the binding affinity between these inhibitors and integrase.

关键词： HIV integrase inhibitors quinolines comparative molecular field analysis AutoDock