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Journal of Systems Science & Complexity 2010年第2期23卷 270-278页

作者： Feng LIU Shige PENG School of ElecLronics and Information Engineering Beijing Jiaotong University Beijing 100044 China. School of Mathematics and System Sciences Shandong University Ji'nan 250100 China

This paper investigates the controllability problem of time-variant linear stochastic controlsystems.A sufficient and necessary condition is established for stochastic exact controllability,whichprovides a useful algebraic criterion for stochastic control ***,when the stochasticsystems degenerate to deterministic systems,the algebraic criterion becomes the counterpart for thecomplete controllability of deterministic control systems.

关键词： Backward stochastic differential equation (BSDE) E-well-posedness Stochastic controlsystem stochastic exact controllability.

A theoretical analysis of optical-to-THz conversion efficiency via optical rectification

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Science china(Technological Sciences) 2008年第12期51卷 2080-2088页

作者： LI DeHua1,QI XiaoDong2 & LIU ShengGang3 1 Terahertz Institute of shandong University of Science & Technology,Qingdao 266510,china 2 Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,china 3 Terahertz research center,Physical electronics College,University of electronics Science,Chengdu 610054,china Terahertz Institute of shandong University of Science & Technology Qingdao China Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun China Terahertz research center Physical Electronics College University of Electronics Science Chengdu China

A theoretical analysis of an ultra-short pulse converted to Terahertz radiation via optical rectification in nonlinear optical crystal is presented here;several factors that affect optical-to-THz conversion efficiencies are discussed;pulse durations affect the conversion efficiency effectively:when crystal length is equal to the optimal crystal length lc,optical-to-THz conversion efficiency is the highest,but for the periodically-inverted electro-optic crystals,conversion efficiency is almost proportional to the crystal length when absorption can be *** account of the absorption of crystals,effective length of crystal is Leff=0.63/α,there is no apparent increase of conversion efficiency and the conversion efficiency approaches to a constant eventually when the crystal length is increased.

关键词： optical rectification periodically inverted effective length conversion efficiency

The dynamical properties of Rydberg hydrogen atom near a metal surface

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 667-675页

作者： GE Meihua1, ZHANG Yanhui1, WANG Dehua2, DU Mengli3 & LIN Shenglu1 1. College of Physics and electronics, shandong Normal University, Jinan 250014, china 2. Department of Mathematics and Physics, shandong Institute of Architecture and Engineering, Jinan 250014, china 3. Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080, china College of Physics and electronics Shandong Normal University Jinan China Department of Mathematics and Physics Shandong Institute of Architecture and Engineering Jinan China Institute of Theoretical Physics Chinese Academy of Sciences Beijing China

The dynamical properties of Rydberg hydrogen atom near a metal surface are presented by using the methods of phase space analysis and closed orbit theory. Transforming the coordinates of the Hamiltonian, we find that the phase space of the system is divided into vibrational and rotational region. Both the Poincaré surface of section and the closed orbit theory verify the same conclusion clearly. In this paper we choose the atomic principal quantum number as n = 20. The dynamical character of the exited hydrogen atom depends sensitively on the atom-surface distance d. When d is sufficiently large, the atom-surface potential can be expressed by the traditional van der Waals force and the system is integrable. When d becomes smaller, there exists a critical value dc. For d > dc, the system is near-integrable and the motion is regular. While chaotic motion appears for d < dc, and the system tends to be non-integrable. The trajectories become unstable and the electron might be captured onto the metal surface.

关键词： Rydberg hydrogen atom, van der Waals interaction, Poincaré surface of section, closed orbit theory, chaos.

Quantitative description of characteristics of high-capacity channels in unconsolidated sandstone reservoirs using in situ production data

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Petroleum Science 2010年第1期7卷 106-111页

作者： Wang Xuezhong Wang Jianyong Wang Chuanfei Zeng Liufang Liu Xuewei Xinjiang Exploration ＆ Production Center Shengli Oilfield Company Sinopec Dongying Shandong 257000 China Sinopec Beijing 100728 China china University of Petroleum Dongying Shandong 257061 China Gudong Oil Production Plant Shengli Oilfield Company Sinopec Dongying Shandong 257237 China Institute of Porous Flow ＆ Fluid Mechanics CNPC ＆ Chinese Academy of Sciences Langfang Hebei 065007 China

Quantitative description of the high-capacity channels in unconsolidated sandstone reservoirs, into which water was injected to improve oil recovery, is a hot topic in the field of reservoir development. This paper presents a novel approach to describing quantitatively the characteristics of connected macropores in unconsolidated sandstone reservoirs using in situ production data. Based on physical simulation for formation mechanisms of high capacity channels and interwell tracer test data, a mathematical model was established to describe high-capacity channels by grey correlation theory, flow mechanism of fluid in porous media and reservoir engineering, and a program was developed to describe quantitatively the channel characteristics. The predicted results were consistent with field monitoring data （80%）, so this model could be economically and effectively used to identify high-capacity channels.

关键词： High-capacity channel unconsolidated sandstone quantitative description physical simulation interwell tracer grey correlation theory

Study on Simulation of Machining Errors Caused by Cutting Force

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武汉理工大学学报 2006年第S1期28卷 167-172页

作者： SHAO Xiaodong1,ZHANG Liu2,LIN Zhaoxu1 (1. School of Mechano-electronic Engineering,Xidian University,Xi’an 710071,china 2. 14th Institute of china electronics Technology company,Najin 200013,china) School of Mechano-electronic Engineering Xidian UniversityXi'an 710071China 14th Institute of china electronics Technology company Najin 200013China

Machining errors caused by cutting force are studied in this paper,and an algorithm to simulate errors is putted forward. In the method,continuous machining process is separated into many machining moments. The deformation of work-piece and cutter at every moment is calculated by finite element method. The machined work-piece is gained by Boolean operation between deformed work-piece and cutter. By analyzing data of final work-piece,machining errors are predicted. The method is proved true by experiment.

关键词： machining error simulation cutting force FEM

Numerical simulation of profile control by clay particles after polymer flooding

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Petroleum Science 2010年第4期7卷 509-514页

作者： Feng Qihong Shi Shubin Wang Sen Zheng Lu School of Petroleum Engineering China University of Petroleum Qingdao Shandong 266555 China School of Petroleum Engineering China University of Petroleum Beijing 102249 China Shengli Oil Production Research Institute SINOPEC Dongying Shandong 257000 China Bozhong Operation company CNOOC Tianjin 300452 China

A three-dimensional,two-phase,five-component mathematical model has been developed to describe flow characteristics of clay particles and flocs in the profile control process,in which the clay particle suspension is injected into the formation to react with residual *** model considers the reaction of clay particles with residual polymer,apparent viscosity of the mixture,retention of clay particles and flocs,as well as the decline in porosity and permeability caused by the retention of clay particles and flocs.A finite difference method is used to discretize the equation for each component in the *** Runge-Kutta method is used to solve the polymer flow equation,and operator splitting algorithms are used to split the flow equation for clay particles into a hyperbolic equation for convection and a parabolic equation for diffusion,which effectively ensures excellent precision,high speed and good *** numerical simulation had been applied successfully in the 4-P1920 unit of the Lamadian Oilfield to forecast the blocking capacity of clay particle suspension and to optimize the injection parameters.

关键词： Clay particles flocs detention operator splitting algorithms numerical simulation

Modeling on Heat and Mass Transfer in Stored Wheat during Forced Cooling Ventilation

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Journal of Thermal Science 2010年第2期19卷 167-172页

作者： Yuancheng WANG,Haifeng DUAN,Hao ZHANG and Zhaohong FANG College of Thermal Energy Engineering,shandong Jianzhu University,Jinan 250101,china College of Thermal Energy Engineering Shandong Jianzhu University Jinan China

A mathematical model based on the theory of heat and mass transfer in porous media was developed to simulate the evolution of grain temperature and moisture content in a wheat storage bin during ventilation with cooling air at the constant temperature and *** the previous works on this aspect,the present work was not focused on cooling the stored grain by ventilation with ambient air,but with the refrigerated *** was performed by comparing between predicted and measured grain temperature and grain moisture content for two *** data were in reasonable good agreement with measured *** model and the parameter values used in the model are applicable for predicting temperature and moisture of stored grains under ventilation conditions.

关键词： Heat and moisture transfer Numerical simulation Aeration Stored grains

Numerical simulation of the blocking process of gelled particles in porous media with remaining polymers

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Petroleum Science 2009年第3期6卷 284-288页

作者： Feng Qihong Zhang Ge Yin Xiaomei Luan Zhiyong School of Petroleum Engineering China University of Petroleum Dongying Shandong 257061 China Oil Production Research Institute Shengli Oilfield Company Sinopec Dongying Shandong 257000 China

Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect （reacting with polymers）, and then the injection profiles are significantly modified. At present, research on gelled particles is mainly focused on laboratory studies of drive mechanisms, and rarely on mathematical models describing the blocking process of gelled particles. In this paper, the blocking process of gelled particles is divided into two sub-processes： deposition and desorption due to particle deformation. A mathematical model based on filtration theory is proposed considering the effect of characteristics of gelled particles on the blocking process. Blocking laws were simulated and researched using the mathematical model. Results of the simulation of the blocking of gelled particles are quite consistent with the experimental results, which confirms the reliability of the mathematical model developed.

关键词： Gelled particles profile control blocking process numerical simulation swelling synergetic effect deformation

Synthesis of GaN nanorods on Si substrates with assistance of the vola-tilization of ZnO middle layers

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Rare Metals 2005年第2期24卷 110-114页

作者： ZHUANGHuizhao GAOHaiyong XUEChengshan WANGShuyun DONGZhihua HEJianting CollegeofPhysicsandelectronics ShandongNormalUniversityJinan250014China

GaN nanorods have successfully been synthesized on Si(111) substrates via ammoniating ZnO/Ga2O3 films at 950 degrees C. Ga2O3 thin films and ZnO middle layers were deposited in turn on Si(111) substrates by r.f. magnetron sputtering system. ZnO volatilized at 950 degrees C in the ammonia ambience and Ga2O3 reacted to NH3 to fabricate GaN nanorods in the later ammoniating process. The volatilization of ZnO layers played an important role in the fabrication. The structure and composition of the GaN nanorods were studied by X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR). The morphology of GaN nanorods was investigated using scanning electron microscopy (SEM) and transmission electronic microscope (TEM). The analyses of measured results revealed that GaN nanorods with hexagonal wurtzite structure were prepared by this method.

关键词： semiconductor materials GaN nanorods r.f. magnetron sputtering ZnO/Ga2O3 films