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Semantic theory of finite lattice-valued propositional logic

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Science China(Information Sciences) 2010年第10期53卷 2022-2031页

作者： PAN XiaoDong 1,2.& XU Yang 2.1 School of maths, southwest jiaotong university, {2., China 2.Intelligent Control Development Center, southwest jiaotong university, {2., China 1. School of maths Southwest Jiaotong University Chengdu 610031 China2. Intelligent Control Development Center Southwest Jiaotong University Chengdu 610031 China

Based on the methodology of Pavelka’s fuzzy propositional logic, in this paper, by combining L-fuzzy set and classical two-value propositional logic theory, a kind of graded semantic theory in lattice-valued propositional logic based on finite lattice implication algebras is established. The notions of L-tautology and L-contradiction are introduced, and several theorems about the relations among different kinds of L-tautologies are given. From the viewpoint of uncertainty reasoning, the notion of satisfiability with certain level for a set of formulas is also defined. On this basis, the semantic consequence operation concerning a set of formulas is proposed, and the properties of semantic consequence operation and the consistency of fuzzy information are discussed.

关键词： lattice-valued propositional logic semantic theory L-tautology consistency lattice implication algebra

Design of a 400 N and 12.mm Mechanical Air Gap High Temperature Superconducting Linear Synchronous Motor

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稀有金属材料与工程 2011年第S3期40卷 319-321页

作者： Yen Fei1,2.3, Li Jing1,2.3, Zheng Shijun1,2.3, Jiang Donghui1,2.3, Liu Lu1,2.3, Liu Wei1,2.3, Ma Guangtong1,2.3, Wang Jiasu1,3, Wang Suyu1,3 1 Applied Superconductivity Laboratory, southwest jiaotong university, chengdu 610031, China 2.State Key Laboratory of Traction Power, southwest jiaotong university, chengdu 610031, China 3 National Laboratory for Rail Transit, chengdu 610031, China SW jiaotong Univ Appl Superconduct Lab Chengdu 610031 Peoples R China SW jiaotong Univ State Key Lab Tract Power Chengdu 610031 Peoples R China Natl Lab Rail Transit Chengdu 610031 Peoples R China

The static thrust output on a superconducting coated conductor coil at different excitation and alternating current suspended above a three phase alternating current long-stator comprised of copper coils is presented. Excitation current up to 45 A was applied through the superconducting coil acting as the excitation system of the superconducting linear synchronous motor (SLSM), alternating current up to 9 A was applied to the armature and magnetic air gaps of 10 and 15 mm were investigated for four different cases; coreless, with an iron core or yoke and both a core and yoke. By scaling up and converting the studied superconducting single pancake racetrack coil into a double pancake coil and connecting four of such coils in series, an SLSM prototype capable of generating 400 N of thrust output and 1 kW of power output with a 12.mm mechanical air gap operating at 77 K is proposed.

关键词： high temperature superconductivity linear synchronous motor long stator motor superconducting coil force measurements

Strengths and Fracture Mechanisms of Al_2._3 Short Fiber Reinforced Al-Mg Alloy Matrix Composite at Elevated Temperatures

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Journal of Materials Science & Technology 2002年第3期18卷 257-260页

作者： Guozheng KANGDepartment of Applied Mechanics and Engineering, southwest jiaotong university, chengdu 610031, ChinaChuan YANG and Jixi ZHANGDepartment of Materials Engineering, southwest jiaotong university, chengdu 610031, China [ Manuscript received Janu SW jiaotong Univ Dept Appl Mech & Engn Chengdu 610031 Peoples R China SW jiaotong Univ Dept Mat Engn Chengdu 610031 Peoples R China

Using the experimental and theoretical methods, the tensile strengths and fracture mechanisms of AI2.3 short fiber reinforced AI-Mg alloy matrix composite at elevated temperatures were researched. The interfacial microstructural characteristics and the fracture surfaces of the composite at different temperatures were observed by transmission electron microscope (TEM) and by scanning electron microscope (SEM), respectively. Then, from the results of microscopic observation, the fracture mechanisms of the composite at different temperatures are discussed. Finally, the tensile strengths of the composite at elevated temperatures were predicted by statistical integration average (SIA) method with the consideration of various fracture mechanisms. It was shown that the strengths and fracture mechanisms of the composite at elevated temperature (300℃) were significantly different from those at room temperature due to the variations of interfacial bonding states. The tensile strengths predicted by the SIA method at elevated temperatures agreed well with the experimental results.

关键词： Fracture A12.3 Al-Mg alloy Composite

MOTION TYPES AND CHAOS OF MULTI-BODY SYSTEMS VIBRATING WITH IMPACTS

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Acta Mechanica Sinica 1991年第4期7卷 369-375页

作者： Shu Zhongzhou southwest jiaotong university,chengdu 610031,China 1. southwest jiaotong university 610031 Chengdu China

In this paper,the limit sets theory for an autonomous dynamical system is generalized to a multi-body system vibrating with *** discover that if every motion of the system is bounded,it has only four different types:periodic motion 7 t,non-periodic recurrent motion γ2.and non-Poisson stable mo- tions γ3 and γ4 approaching γ1 and γ2. respectively.γ2.is the source of *** is very interesting that cha- otic motions seem stochastic but possess the character of *** way of example,we discuss chaotic motions of a small ball bouncing vertically on a massive vibrating *** result obtained by us is different from that obtained by Holmes.

关键词： multi-body impact vibrations recurrent motion chaos

A new real-time eye tracking based on nonlinear unscented Kalman filter for monitoring driver fatigue

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控制理论与应用（英文版） 2010年第2期8卷 181-188页

作者： Zutao ZHANG 1 , 2., Jiashu ZHANG 2.(1.School of Mechanical Engineering, southwest jiaotong university, chengdu Sichuan {2., China 2.Sichuan Key Lab of Signal and Information Processing, southwest jiaotong university, chengdu Sichuan {2., China) School of Mechanical Engineering Southwest Jiaotong University Chengdu Sichuan China Sichuan Key Lab of Signal and Information Processing Southwest Jiaotong University Chengdu Sichuan China

A new scheme for driver fatigue detection is presented, which is based on the nonlinear unscented Kalman filter and eye tracking. Assuming a probability distribution than to approximate an arbitrary nonlinear function or transformation, eye nonlinear tracking can be achieved using an unscented transformation (UT), which adopts a set of deterministic sigma points to match the posterior probability density function of the eye movement. Driver fatigue can be detected using the percentage of eye closure (PERCLOS) framework in a realistic driving condition after the eye nonlinear tracking. This system was tested adequately in realistic driving environments with subjects of different genders, with/without glasses, in day/night driving, being commercial/noncommercial drivers, in continuous driving time, and under different road conditions. The last experimental results show that the proposed method not only improves the robustness for nonlinear eye tracking, but also can provide more accurate estimation than the traditional Kalman filter.

关键词： Eye tracking Unscented Kalman filter (UKF) Fatigue detection PERCLOS

Analysis of the Effects of Slope Geometry on the Dynamic Response of a Near-field Mountain from the Wenchuan Earthquake

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Journal of Mountain Science 2010年第4期7卷 353-360页

作者： XIAO Shiguo FENG Wenkai ZHANG Jianjing Department of Geoteehnical Engineering Southwest Jiaotong University Chengdu 610031 China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China Department of C-eoteehnical Engineering Southwest Jiaotong University Chengdu 610031 China

Fourier spectra and acceleration response spectra of near-field acceleration records of the 2.08 Wenchuan Earthquake have been *** fundamental frequencies(or predominant periods) were ***,the natural frequencies of a range of slopes with different geometric characteristics,such as height,slope ratio,and pattern,were *** seismic responses of the slopes were compared,and the variability of seismic response with the above geometric elements was *** show that if slope height increases,and provided that other conditions are unchanged,the natural frequency of the first mode of a doublesurface slope will change as a power ***,natural frequencies will diminish(based on a parabolic function) as the slope angle becomes *** the surface pattern and the number of surfaces on a slope can have a great impact on the seismic response of the ***,within a certain range of slope heights or angles,either height or angle will also greatly influence the variability of the seismic *** results of this research will be helpful to understanding seismic dynamic response features and explaining the ways that slope stability can be affected by earthquakes.

关键词： Wenchuan Earthquake Slope Geometric features Dynamic response Naturalfrequency

ELASTIC-PLASTIC FINITE ELEMENT ANALYSIS OF THREE-DIMENSIONAL CONTACT-IMPACT AT RAIL JOINT

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 411-416页

作者： Wen ZefengJin XuesongZhang WeihuaNational Traction Power Laboratory,southwest jiaotong university,chengdu 610031, China southwest jiaotong university National Traction Power Laboratory Chengdu 610031

Using the finite element code ANSYS/LS-DYNA, a dynamic finite element modelwith an elastic-linear-kinematic-hardening plastic material is established to analyzeelastic-plastic stresses in the railhead in the impact process of wheel and rail occurring at thegap of rail joint. The model is based on the discrete elastic support condition of the rails, whichis suitable for the actual situation of wheel/track rolling contact. In the analysis the influencesof axle load, yield stress and tangent modulus of rail material on the stresses and strains areinvestigated in detail. The distribution of stresses and strains in the jointed railhead are *** is found that the axle load, yield stress and tangent modulus of rail material greatly affect thestresses and strains in the railhead during impacting. The study provides a reliable method anduseful datum for the further research on fatigue and wear of railhead and improving the rail jointmode.

关键词： Wheel/rail Rail joint Elastic-plastic Contact-impact Finite elementmethod

Cracking Behaviour of Al_2._3 Short Fibre/Al-5.5Zn Composite in TEM

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Journal of Materials Science & Technology 1997年第3期13卷 235-237页

作者： Xiyan ZHANG Tianxin TAN Wenyi PENG and Qing GAO (southwest jiaotong university, chengdu 610031, China) southwest jiaotong university Chengdu 610031 China

The micromechanical behaviour of Al2.3 short fibre reinforced Al-5.5Zn matrix composite has been in-situ studied by using TEM. The results show that in the composite the nucleation and propagation of cracks take place mainly in the matrix, as well as in the region near the fibre/matrix interface. It has been also observed that the microcracks can close during *** the fracture property can be characterized by crack open displacement (COD). The cracking characteristic may result from the large strength difference between the matrix and fibre.

关键词： Cracking Behaviour of Al2.3 Short Fibre/Al-5.5Zn Composite in TEM Al Zn

STUDY ON DYNAMIC CURVING BEHAVIOR OF TILTING PASSENGER CARS

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 360-365,371页

作者： Liu Hongyou Zeng Jing National Traction Power Laboratory, southwest jiaotong university, chengdu 610031, China National Traction Power Laboratory Southwest Jiaotong University Chengdu 610031 China

By using tilting carbodies, train can negotiate at a higher speed withoutreducing the passenger's ride quality. This is a good method to allow a significant increase inspeed at existing track to improve the railway transportation capability, and to enhance thecompetition ability of railways with other transportation systems. With the increase of the curvenegotiation speed, the wheel-rail lateral forces and wheel-rail wear of the tilting train willincrease. The self-steering radial bogie is an effective way to solve the problem. The dynamic modelof the tilting passenger car with self-steering bogies is established in detail, and the curvingperformance of the car is investigated.

关键词： tilting passenger car self-steering bogie dynamic curving behavior wheel-rail interaction