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Study on the holistic model for water resources system

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Science China(Technological Sciences) 2004年第Z1期47卷 72-89页

作者： ZHAO Jianshi WANG Zhongjing WENG Wenbin Department of Hydraulic Engineering Tsinghua University Beijing 100084 China Department of Hydraulic Engineering Tsinghua University Beijing 100084 China Department of Hydraulic Engineering Tsinghua University Beijing 100084 China

Based on the Theory of Complex Adaptive system developed recently, a holistic model for water resources system is established at the basin level for analyzing water resources management and allocation of the basin. In this holistic model framework, the subsystems of the water resources system, including hydrologic components, agricultural and industrial production, human living, ecosystem and enviorenment are combined in a dynamic connection with inner variables. According to the characteristics of the holistic model framework, a nesting genetic arithmetic is employed to solve the nonlinear optimal model. The model is applied in the Yellow River basin to analyze the rational amount of diversion water for the West Line of Water Transfer Project form South China to North China and its marginal benifit.

关键词： water resources, holistic model, complex adaptive system, genetic arithmetic.

Study of the circulation theory of the cooling system in vertical evaporative cooling generator

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Science China(Technological Sciences) 2006年第3期49卷 358-364页

作者： YU Shunzhou1, CAI Jing2, GUO Chaohong1 & GU Guobiao1 1. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080, China 2. Beijing Changcheng Institute of Metrology and Measurement, Beijing 100095, China Institute of Electrical Engineering Chinese Academy of Sciences Beijing China Beijing Changcheng Institute of Metrology and Measurement Beijing China

The article briefly states the current development of evaporative cooling generator and its advantages comparing with generators of traditional cooling. Vertical evaporative cooling generator, which adopts Close-Loop-Self-Cycle with no-pump and free convection boil in the hollow stator bar, is one of the great developments in generator design. This article emphasizes the importance of cooling system in generator; expatiates the circulation theory in two aspects, energy and flow; and analyzes the essential reason, motivity and stability of Close-Loop-Self-Cycle. The article points out that the motivity of the circulation is the heat absorbed by coolant. After absorbing heat the coolant will have the ability of doing work because of the phase change. In another words, it is the buoy- ancy causing by density difference leads to the Close-Loop-Self-Cycle. This conclusion is validated by experimental data.

关键词： vertical evaporative cooling generator, cooling system, circulation theory.

Differential topological characteristics of the DSR on injection space of electrical power system

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Science China(Technological Sciences) 2002年第6期45卷 576-584页

作者：余贻鑫曾沅冯飞 Sch. Elec. Automat. and Ener. Eng. Tianjin University Tianjin 300072 China

This paper analyzes the differential topological characteristics of the dynamic security region (DSR) on injection space of electrical power system by differential topology theories. It is shown that the boundary of the DSR on injection space has no suspension and is compact, and there are no holes inside the DSR defined based on controlling unstable equilibrium point (UEP) method. The 10-generator, 39-bus New England Test system, is taken as an example to show these characteristics of the DSR on injection space.

关键词： electrical power system, dynamic security region, differential topological characteristics.

A new method for the fast simulation of models of highly dependable Markov system

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Science China(Technological Sciences) 2005年第1期48卷 23-30页

作者： XIAO Gang LI Zhizhong Department of Industrial Engineering Tsinghua University Beijing 100084 China Department of Industrial Engineering Tsinghua University Beijing 100084 China

To fast evaluate the small probability that starts from the all-components-up state, the system hits the failed sets before returning to the all-components-up state, Important Sampling or Important Splitting is used commonly. In this paper, a new approach distinguished from Important Sampling and Important Splitting is presented to estimate this small probability of highly dependable Markov system. This new approach achieves variance reduction through improving the estimator itself. The new estimator is derived from the integral equation describing the state transitions of Markov system. That the variance of this estimator is less than that of naive simulation at all time is proved theoretically. Two example involved reliability models with deferred repair are used to compare the methods of RB, IGBS, SB-RBS, naive simulation, and the method presented in this paper. Results show our method has the least RE.

关键词： statistical estimator, variance reduction, dependability measures, Markov system, integral equation.

Structures and stability of isomers of[Si,N,N,P]system

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Science China Chemistry 2004年第2期47卷 98-105页

作者： KAN Wei1, YU Haitao1, LI Mingxia1, FU Honggang1,2 & SUN Jiazhong1,2 1. College of Chemistry and Chemical Engineering, Heilongjiang University, Harbin 150080, China 2. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China College of Chemistry and Chemical Engineering Heilongjiang University Harbin China State Key Laboratory of Theoretical and Computational Chemistry Institute of Theoretical Chemistry Jilin University Changchun China

Some stationary points on the potential energy surface of [Si, N, N, P] system were located at the B3LYP/6-311G(d) and QCISD(t)/6-311+G(2df)(single-point) levels of theory, while the isomerization, structures, and stability of these obtained isomers were suggested. The computed results indicate that only four-membered ring isomer SiNPN(E1, 2A″ ), which pos-sesses butterfly-like structure and Si-P cross bonding, is kinetically stable in all optimized iso-mers. Other isomers may be considered as kinetically unstable towards isomerization or disso-ciation because of the corresponding smaller reaction barriers. Furthermore, the present paper also proposes electronic and geometric structures, vibrational frequencies and the corresponding vibrational modes, dipole moments, and rotational constants of isomer E1. To make use of the computed results, we can clearly know that the reaction pathway via an intermediate E3 (SiNPN) is the most favorable channel producing isomer E1 from fragments SiN (2P) and PN (1S), which have been well characterized in space, and thus, isomer E1 can be considered as a candidate for interstellar observation. The reaction enthalpy of SiN (2P) + PN(1S)→E1 and the standard en-thalpy of formation of isomer E1 are 215.25 and 457.99 kJ/mol, respectively, at 298.15 K.

关键词： potential energy surface, [Si,N,N,P] system, isomerization, kinetic stability.

Phase behavior and structure analysis of the middle mixed layer for ASP flooding system at low surfactant concentration

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Science China Chemistry 2002年第2期45卷 184-190页

作者：牟建海李干佐廖广志黄丽赵孔双 Key Laboratory for Colloid and Interface Chemistry of the Ministry of Education Shandong University Jinan 250100 China

The phase behavior and interfacial tension of alkali/surfactant/polymer (ASP) flooding system and simulative crude oil were investigated, and the size distribution and structure analysis of the middle mixed layer (MML) were also studied by size analyzer and freeze-fracture TEM. It was found that there were some rules between the volume of MML and the concentration of each component, and the interfacial tension between MML and the oil phase or water phase could reach an ultra-low value. Especially, the freeze-fracture TEM micrographs of MML were firstly obtained, and the new viewpoint was put forward that there coexist the structures of micelle, microemulsions and emulsions in MML and the structure of microemulsion is dominant. This would make an important effect on the research of surfactant theory and ASP flooding mechanism.

关键词： ASP flooding system, phase behavior, microemulsion, emulsion, freeze-fracture TEM.

Wave-front correction of high-intensity fs laser beams by using closed-loop adaptive optics system

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Science China(Physics,Mechanics & Astronomy) 2005年第1期48卷 122-128页

作者： WANG Zhaohua JIN Zhan ZHENG Jiaan WANG Peng WEI Zhiyi ZHANG Jie Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

We developed an adaptive optics system to correct the wave-front distortion of an intense fs laser beam from our multi-TW laser system, Jiguang II. In this paper, the instruments of the adaptive optical system are described and the experimental results of the closed-loop wave-front correction are presented. A distorted laser wave-front of 20 wavelengths of P-V values was corrected to 0.15 wavelength of P-V values. The beam quality of the laser system varies from 3.5 diffraction limit to 1.5 diffraction limit.

关键词： Shack-Hartmann wave-front sensor, adaptive optics system, femtosecond laser, diffraction limit.

Research on dynamic characteristics of multi-sensor system in the case of cross-sensitivity

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Science China(Technological Sciences) 2005年第1期48卷 1-22页

作者： TANG Xiaojun LIU Junhua School of Electrical Engineering Xi'an Jiaotong University Xi'an 710049 China School of Electrical Engineering Xi'an Jiaotong University Xi'an 710049 China

In this study, the dynamic characteristic of a multi-sensor system made up of such sensors as are sensitive to several parameters is discussed, and the effect of cross-sensitivity on the precision of a measurement system is also discussed. A multi-sensor system is looked as a serial of a linear filter and a memoryless nonlinear system, i.e. Wiener system, and the subsequent information fusion system is regarded as a Hammerstein system, i.e. a serial of a memoryless nonlinear system and a linear filter. On the basis of static calibration, it is presented to determine the inverse filter in a Hammerstein system using blind deconvolution. In order to control the uncertainty of amplitude of signals recovered by blind deconvolution well, a regulation approach to regulating the inverse linear filter coefficient matrixes is presented according to the identity between inverse filter coefficient matrixes and static calibrating matrix. So the approximate inverse dynamic model of multi-sensor system is obtained, the degree of distortion of dynamic measurement result is reduced, the measurement precision is improved, and the need of practice can be reached. Simulation example and simulation result show that the recovered error of the inputs of sensor system, the frequency of which is 1/10 of sampling frequency, is 1/20 of the measurement results without dynamic compensation, and is one half of the measurement results with sole dynamic compensation, and the rapidity is improved 2 times. The dynamic compensation results of a metal oxide semiconductor methane sensor show that the dynamic measurement error is less than one half of that without dynamic compensation. So this method expands the bandwidth of multi-sensor system.

关键词： dynamic compensation, multi-sensor system, cross-sensitivity, blind deconvolution.

Uniform blow-up profiles and boundary layer for a parabolic system with localized nonlinear reaction terms

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Science China Mathematics 2005年第2期48卷 185-197页

作者： LI Huiling & WANG Mingxin Department of Mathematics, Southeast University, Nanjing 210018, China Department of Mathematics, Xuzhou Normal University, Xuzhou 221116, China Department of Mathematics Southeast University Nanjing China Department of Mathematics Xuzhou Normal University Xuzhou China

This paper deals with the blow-up properties of the solution to a semilinear parabolic system with localized nonlinear reaction terms, subject to the null Dirichlet boundary condition. We first give sufficient conditions for that the classical solution blows up in the finite time, secondly give necessary conditions and a sufficient condition for that two components blow up simultaneously, and then obtain the uniform blow-up profiles in the interior. Finally we describe the asymptotic behavior of the blow-up solution in the boundary layer.

关键词： parabolic system, localized nonlinear reaction terms, blow-up profiles, boundary layer size.