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Particuology 2018年第2期16卷 91-98页

作者： Zhixiong zhang Wenhui yuan Li Li School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 China College of Environmental Science and Engineering South China University of Technology Guangzhou 510006 China

To improve the electrolyte wettability and thermal stability of polypropylene （PP） separators, nano- SiO2/poly（vinyl alcohol）-coated PP composite separators were prepared using a simple but efficient sol-gel and dip-coating method. The effects of the tetraethoxysilane （TEOS） dosage on the morphology, wettability, and thermal stability of the composite separators were investigated using Fourier-transform infrared spectroscopy, scanning electron microscopy, and contact-angle measurements. All the composite separators gave a smaller contact angle, higher electrolyte uptake, and lower thermal shrinkage compared with the PP separator, indicating enhanced wettability and thermal stability. Unlike the case for a traditional physical mixture, Si-O-C covalent bonds were formed in the coating layer. The composite separator with a TEOS dosage of 7.5 wt% had a unique porous structure combining hierarchical pores with interstitial voids, and gave the best wettability and thermal stability. The ionic conductivity of the composite separator containing 7.5 wt% TEOS was 1.26 mS/cm, which is much higher than that of the PP separator （0.74 mS/cm）. The C-rate and cycling performances of batteries assembled with the composite separator containing 7.5 wt% TEOS were better than those of batteries containing PP separators.

关键词： Wettability Thermal stability Composite separator Lithium-ion batteries

Data Driven CAN Node Reliability Assessment for Manufacturing System

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Chinese Journal of Mechanical Engineering 2017年第1期30卷 190-199页

作者： zhang Leiming yuan Yong LEI Yong State Key Laboratory of Fluid Power & Mechatronic Systems Zhejiang University State Key Laboratory of Automotive Safety and Energy Tsinghua University

The reliability of the Controller Area Network（CAN） is critical to the performance and safety of the system. However, direct bus-off time assessment tools are lacking in practice due to inaccessibility of the node information and the complexity of the node interactions upon errors. In order to measure the mean time to bus-off（MTTB） of all the nodes, a novel data driven node bus-off time assessment method for CAN network is proposed by directly using network error information. First, the corresponding network error event sequence for each node is constructed using multiple-layer network error information. Then, the generalized zero inflated Poisson process（GZIP） model is established for each node based on the error event sequence. Finally, the stochastic model is constructed to predict the MTTB of the node. The accelerated case studies with different error injection rates are conducted on a laboratory network to demonstrate the proposed method, where the network errors are generated by a computer controlled error injection system. Experiment results show that the MTTB of nodes predicted by the proposed method agree well with observations in the case studies. The proposed data driven node time to bus-off assessment method for CAN networks can successfully predict the MTTB of nodes by directly using network error event data.

关键词： bus-off monitoring Controller Area Network industrial automation

MINIMIZATION PROBLEM FOR SYMMETRIC ORTHOGONAL ANTI-SYMMETRIC MATRICES

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Journal of Computational Mathematics 2007年第2期25卷 211-220页

作者： yuan Lei Anping Liao Lei zhang College of Mathematics and Econometrics Hunan University Changsha 410082 China Department of Information and Computing Science Changsha University Changsha 410003 China

By applying the generalized singular value decomposition and the canonical correlation decomposition simultaneously, we derive an analytical expression of the optimal approximate solution ^-X, which is both a least-squares symmetric orthogonal anti-symmetric solu- tion of the matrix equation A^TXA = B and a best approximation to a given matrix X^＊. Moreover, a numerical algorithm for finding this optimal approximate solution is described in detail, and a numerical example is presented to show the validity of our algorithm.

关键词： Symmetric orthogonal anti-symmetric matrix Generalized singular value decomposition Canonical correlation decomposition

A self-tuning control method for Wiener nonlinear systems and its application to process control problems

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Chinese Journal of Chemical Engineering 2017年第2期25卷 193-201页

作者： Ping yuan Bi zhang Zhizhong Mao College of Information Science & Engineering Northeastern University Shenyang 110819 China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang 110819 China

Many chemical processes can be modeled as Wiener models, which consist of a linear dynamic subsystem followed by a static nonlinear block. In this paper, an effective discrete-time adaptive control method is proposed for Wiener nonlinear systems with uncertainties. The parameterization model is derived based on the inverse of the nonlinear function block. The adaptive control method is motivated by self-tuning control and is derived from a modified Clarke criterion function, which considers both tracking properties and control efforts. The uncertain parameters are updated by a recursive least squares algorithm and the control law exhibits an explicit form. The closed-loop system stability properties are discussed. To demonstrate the effectiveness of the obtained results, two groups of simulation examples including an application to composition control in a continuously stirred tank reactor(CSTR) system are studied.

关键词： Wiener systemsAdaptive controlUncertaintiesStabilityCSTR

Nonlinear magneto-electric response of a giant magnetostrictive/piezoelectric composite cylinder

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Acta Mechanica Sinica 2012年第2期28卷 385-392页

作者： yuan-Wen Gao Juan-Juan zhang Key Laboratory of Mechanics on Western Disaster and Environment Ministry of Education and College of Civil Engineering and MechanicsLanzhou University730000 LanzhouChina

In this study, we investigate the nonlinear cou- pling magneto-electric （ME） effect of a giant magnetostric- tive/piezoelectric composite cylinder. The nonlinear consti- tutive relations of the ME material are taken into account, and the influences of the nonlinear material properties on the ME effect are investigated for the static and dynamic cases, respectively. The influences of different constraint conditions on the ME effect are discussed. In the dynamic case considering nonlinear material properties, the double frequency ME response （The response frequency is twice the applied magnetic frequency） is obtained and discussed, which can be used to explain the experiment phenomenon in which the input signal with frequency f is converted to the output signal with 2f in ME laminated structures. Some calculations on nonlinear ME effect are conducted. The obtained results indicate that the nonlinear material properties affect not only the magnitude of the ME effect in the static case but also the ME response frequency in the dynamic case

关键词： Nonlinear coupling ME effect Layered com- posite cylinder. Double frequency ME response

Continuum damage mechanics for sintered powder metals

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Science China(Physics,Mechanics & Astronomy) 2015年第1期58卷 95-106页

作者： yuan Huang MA SongYun zhang Long Beijing Institute of Technology School of Mechanical Engineering University of Wuppertal Department of Mechanical Engineering

Sintered metals are characterized by the high porosity(8%)and voids/micro-cracks in *** behavior of the materials is coupled with micro-crack propagation and coalescence of open *** the present work the damage evolution of the sintered iron under multi-axial monotonic loading conditions was investigated experimentally and *** tests indicated that damage of the sintered iron initiated already at a stress level much lower than the macroscopic yield *** damage process can be divided into the stress-dominated elastic damage and the plastic damage described by the plastic *** on the uniaxial tensile tests an elastic-plastic continuum damage model was developed which predicts both elastic damage and plastic damage in the sintered iron under general multi-axial monotonic loading *** predictions agree with experiments with different multi-axial loading paths.A phenomenological continuum damage model for the sintered metal is developed based on the experimental observations to predict the inelastic behavior and damage process to failure under multi-axial loading *** proposed damage model is experimentally verified under different loading conditions.

关键词： sintered metal porous material damage evolution multi-axial damage continuum damage model

An Active-Set Projected Trust Region Algorithm for Box Constrained Optimization Problems

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Journal of Systems Science & Complexity 2015年第5期28卷 1128-1147页

作者： yuan Gonglin WEI Zengxin zhang Maojun College of Mathematics and Information Science Guangxi University School of Mathematic and Computing Science Guilin University of Electronic Technology

An active-set projected trust region algorithm is proposed for box constrained optimization problems, where the given algorithm is designed by three steps. First, the projected gradient direction which normally has better numerical performance is introduced. Second, the projected trust region direction that often possesses good convergence is defined, where the matrix of trust region subproblem is updated by limited memory strategy. Third, in order to get both good numerical performance and convergence, the authors define the final search which is the convex combination of the projected gradient direction and the projected trust region direction. Under suitable conditions, the global convergence of the given algorithm is established. Numerical results show that the presented method is competitive to other similar methods.

关键词： Active-set strategy convergence trust region

Controllability and observability of networked control systems with time-varying delays

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Journal of Systems Engineering and Electronics 2009年第4期20卷 800-806页

作者： Li Jinna zhang Qingling Li yuan Inst. of Systems Science Northeastern Univ. Shenyang 110004 P. R. China Dept. of Mathematics and Physics Shenyang Inst. of Chemical Technology Shenyang 110142 P. R. China

The controllability and observability of networked control systems are studied. Aiming at the networked control system with time-varying delay, the sufficient and necessary conditions for complete controllability and complete observability of the system are presented, respectively. Because of Markov characteristic of the network-induced delay, in terms of stochastic theory, a sufficient and necessary condition for completely mean value controllability of networked control systems is obtained. Further, the conditions that the controllability and observability of networked control systems are equivalent to the initial time-invariant system are given. Controllability and observability realization indexes are also discussed, respectively. The numerical example demonstrates the effectiveness of the proposed theory.

关键词： networked control system controllability observability controllability realization index observability realization index.

TIME-OPTIMAL INTERPOLATION FOR CNC MACHINING ALONG CURVED TOOL PATHES WITH CONFINED CHORD ERROR

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Journal of Systems Science & Complexity 2013年第5期26卷 836-870页

作者： yuan Chunming zhang Ke FAN Wei Key Laboratory of Mathematics Mechanization Institute of Systems ScienceChinese Academy of Sciences

In this paper, two new interpolation algorithms lot CNC machining along curve^l tom pathes are proposed： a time-optimal interpolation algorithm under chord error, feedrate, and tangential acceleration bounds, and a greedy interpolation algorithm under the chord error and tangential jerk bounds. The key idea is to reduce the chord error bound to a centripetal acceleration bound which leads to a velocity limit curve, called the chord error velocity limit curve. Then, the velocity planning is to find the proper velocity curve governed by the acceleration or jerk bounds ＇~under＂ the chord error velocity limit curve. For two types of simple tool pathes, explicit formulas for the velocity curve are given and the methods are implemented in commercial CNC controllers.

关键词： Chord error CNC interpolation cubic PH curve jerk quadratic B-spline time-optimalvelocity planning velocity limit curve.

Towards Verified Software:Mirror Theory of Programming

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Chinese Journal of Electronics 2017年第2期26卷 279-284页

作者： zhang Junfu ZHAO Wen yuan Chongyi School of Software & Microelectronics Peking University National Engineering Research Center for Software Engineering Peking University

A program,when being executed,acts like a mirror that produces mirror images for objects in front of it.A mirror distinguishes itself from others by the way how it changes the shape of an object.A program can be characterized by the way how the final values of variables(the mirror images) are related to the initial values of variables(the objects).Axioms that specify relationships between final values and initial values of variables in a program are *** logic to be discussed in this paper serves to prove and to deduce properties based on given *** the axioms and the logic belong to a theory,namely the mirror theory of programming,in which a program appears as an operation expression *** is a step forward towards verified software.

关键词： Operation expression Semantic axiom Programming logic Theory of programming Verified software