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Nash-equilibrium strategies of orbital TargetAttacker-Defender game with a non-maneuvering target

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Chinese Journal of Aeronautics 2024年第10期37卷 365-379页

作者： Yifeng LI xi liang Zhaohui DANG School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

This study investigates the orbital Target-Attacker-Defender(TAD)game problem in the context of space *** this game,the Attacker and the Defender compete for a Target that is unable to maneuver due to its original mission *** paper establishes three TAD game models based on the thrust output capabilities:unconstrained thrust output,thrust constrained by an upper bound,and fixed thrust *** models are then solved using differential game theory to obtain Nash equilibrium solutions for the game problems,and the correctness and effectiveness of the solution methods are verified through ***,an analysis of the winning mechanisms of the game is conducted,identifying key factors that influence the game’s outcomes,including weight coefficients in payoffs,the maximum thrust acceleration limit,and the initial game *** the unique characteristics of space missions,a specific focus is given to the analysis of the Defender’s initial states in the hovering formation and in-plane circling formation,revealing overall success patterns for defense strategies from these two *** summary,this study provides valuable insights into the control strategies and winning mechanisms of orbital TAD games,deepening our understanding of these games and offering practical guidance to improve success rates in real-world scenarios.

关键词： Target-Attacker-Defender problem Differential game TPBVP Continuous thrust Orbital game

Mutual eclipses of J2 Europa by J1 Io observed at Yunnan Observatory in 2009

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Research in Astronomy and Astrophysics 2011年第10期11卷 1243-1248页

作者： xi-liang Zhang Zhong Liu National Astronomical Observatories/Yunnan Observatory Joint Laboratory for OpticalAstronomy Chinese Academy of Sciences Kunming 650011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Mutual events between natural satellites include mutual occultation and mutual eclipse. Mutual eclipse is another kind of mutual occultation as viewed from the center of the Sun instead of the Earth. Two mutual eclipses of J2 Europa by J1 Io （2009 Aug. 28 and Sept. 12） were observed at Yunnan Observatory during the PHEMU09 international campaign. We will calculate the astrometric data of these Galilean satellites by analyzing and fitting the light curves we obtained. The limb-darkening was considered during modeling the light intensity of eclipsed satellites in the penumbra zone, by taking the Lommel-Seeliger scattering law into account. Several dynamical quantifies, such as the relative coordinates of the eclipsing satellite from the eclipsed one △α cos δ and △δ, impact parameter and mid-time corresponding to the impact parameter and the deviations O - C of observed △α cos d and △δ relative to ephemerides, were obtained for each event respectively.

关键词： eclipses -- kinematics and dynamics-methods -- planets and satellites individual: Galilean satellites

Spur Gear Tooth Pitting Propagation Assessment Using Model-based Analysis

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Chinese Journal of Mechanical Engineering 2017年第6期30卷 1369-1382页

作者： xi-Hui liang Zhi-liang Liu Jun Pan Ming Jian Zuo Department of Mechanical Engineering University of Alberta School of Mechatronics Engineering University of Electronic Science and Technology Key Laboratory of Reliability Technology for Mechanical and Electrical Product of Zhejiang Province Zhejiang Sci-Tech University

Tooth pitting is a common failure mode of a gearbox. Many researchers investigated dynamic properties of a gearbox with localized pitting damage on a single gear tooth. The dynamic properties of a gearbox with pitting distributed over multiple teeth have rarely been investi- gated. In this paper, gear tooth pitting propagation to neighboring teeth is modeled and investigated for a pair of spur gears. Tooth pitting propagation effect on time-vary- ing mesh stiffness, gearbox dynamics and vibration char- acteristics is studied and then fault symptoms are revealed. In addition, the influence of gear mesh damping and environmental noise on gearbox vibration properties is investigated. In the end, 114 statistical features are tested to estimate tooth pitting growth. Statistical features that are insensitive to gear mesh damping and environmental noise are recommended.

关键词： Mesh stiffness Mesh damping Geardynamics Vibration Statistical feature Dynamicsimulation

Square-mean Almost Automorphic Solutions to Some Stochastic Evolution Equations I: Autonomous Case

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Acta Mathematicae Applicatae Sinica 2015年第3期31卷 577-590页

作者： xi-liang LI Yu-liang HAN Bai-feng LIU School of Mathematics and Information Science Shandong Institute of Business and Technology

This paper concerns the square-mean almost automorphic solutions to a class of abstract semilinear functional integro-differential stochastic evolution equations in real separable Hilbert spaces. Under some suitable assumptions, the existence, uniqueness and asymptotic stability of the square-mean almost automorphic mild solution to some stochastic differential equations are established. As an application, we analyze the almost automorphic mild solution to some stochastic partial functional differential equation which turns out to be in good agreement with our abstract results.

关键词： square-mean almost automorphy integro-differential equations stochastic evolution equations.

A Note on Equilibrium of Eventually Strongly Monotone Skew-product Semiflows

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Acta Mathematicae Applicatae Sinica 2010年第2期26卷 307-310页

作者： xi-liang Li Zuo-huan Zheng Shandong Institute of Business and Technology Yantai 264005 China Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190 China

In this paper, we show that for an eventually strongly monotone skew-product semiflow τ, the strict ordering on Ec （the set consisting of continuous equilibria of τ） implies the strong one.

关键词： continuous equilibrium eventually strongly monotone skew-product semiflow

Mechanism of Embrittlement and De-Embrittlement for 2.25Cr-1Mo Steel

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Journal of Iron and Steel Research International 2011年第3期18卷 47-51页

作者： ZHANG xi-liang ZHOU Chang-yu School of Mechanical and Power Engineering Nanjing University of TechnologyNanjing 210009JiangsuChina

The constant embrittlement curve for constant segregation concentration on grain boundary of impurity element P and relationship between equilibrium grain boundary segregation concentration and operation time for 2.25Cr-1Mo steel were derived based on the theory of equilibrium grain boundary *** mechanism of step-cooling test and mechanism of de-embrittlement for 2.25Cr-1Mo steel were *** segregation rate will increase but equilibrium grain boundary segregation concentration of impurity element P will decrease as temperature increases in the range of temper embrittlement *** is one critical temperature of embrittlement corresponding to each embrittlement *** the further heat treating temperature is higher than critical temperature,the heat treating will become a de-embrittlement process;otherwise,it will be an embrittlement *** critical temperature of embrittlement will shift to the direction of low temperature as further *** a result,some stages of step-cooling test would change into a de-embrittlement *** grain boundary desegregation function of impurity element P was deduced based on the theory of element diffusion,and the theoretical calculation and experimental results show that the further embrittlement or de-embrittlement mechanism can be interpreted qualitatively and quantitatively by combining the theory of equilibrium grain boundary segregation with constant embrittlement curve.

关键词： step-cooling test critical embrittlement temperature embrittlement mechanism grain boundary desegregation

Specific Heat of the Spin-1/2 Antiferromagnetic Heisenberg Chain

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Chinese Physics Letters 2001年第9期18卷 1261-1263页

作者： YUN Guo-Hong liang xi-xia Department of Physics Inner Mongolia UniversityHohhot 010021

A simple analytic theory of thermodynamics at finite temperature for the spin-1/2 antiferromagnetic Heisenberg chain is proposed based on the picture of the particle-hole pair excitations. The dispersion relation of the particle-hole pairs is derived in the formulation of thermodynamic Bethe ansatz provided that the particles and holes have the same energy and they are excited as normalmodes. It is shown that the behaviour of the specific heat is in excellent agreement with the numerical and experimental results.

关键词： Heisenberg ferromagnetic thermodynamics

A TRUST REGION-TYPE METHOD FOR SOLVINGMONOTONE VARIATIONAL INEQUALITY

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Journal of Computational Mathematics 2000年第1期18卷 13-24页

作者： xi-ming liang Cheng-xian Xu Ji-xin Qian Institute of Industrial Process Control National Lab of Industrial Control TechnologyZhejiang UniversityHangzhou 310027China School of Science Xi’an Jiaotong UniversityXi’an 710049China

Presents a study which proposed to introduce a trust region-type modification of Newton method for the monotone inequality problem using merit function. Concepts of monotone mapping; Proof of convergence of algorithm ... 详细信息

关键词： variational inequality problem trust region method global convergence quadratic convergence

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

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Optoelectronics Letters 2008年第4期4卷 302-306页

作者： BAO Jin liang xi-xia Departement of Physics Inner Mongolia University Hohhot 010021 China

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, Gaxin1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.

关键词：三元混合晶体声子极化声子成分研究