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Sensors Array Technique for Monitoring Aluminum Alloy Spot Welding

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Transactions of Tianjin University 2010年第5期16卷 322-327页

作者：王蕤罗震单平步贤政袁书现敖三三 school of Material science and engineering Tianjin University

In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot *** sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors *** algorithm based on principal component analysis is proposed to extract the signal *** three types of magnetic sensors array are used in the experiment of monitoring the *** the eigenvalues are extracted,they are used to build a relationship with ...

关键词： spot welding magnetic field sensors array principal component analysis

A review of fluorescence based corrosion detection of metals

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Corrosion Communications 2022年第2期6卷 1-15页

作者： Chao Chen Mei Yu Jiaxing Tong Liangliang Xiong Yingquan Li Xiangxin Kong Jianhua Liu Songmei Li school of Materials science and engineering Beihang University

Fluorescence based corrosion detection has been proposed as a prospective monitoring method for the initial corrosion of metals due to its high sensitivity, non-destructive, in situ and real-time detection. This paper provides a comprehensive and updated review on the fluorescence based corrosion detection of metals. The principles of fluorescence based corrosion detection are introduced according to the corrosion processes of metals. Fluorescent indicators in corrosion detection are classified into pH and metal ion sensitive indicators, which show fluorescence response either by the pH variation or the presence of metallic cations as an early warning for corrosion *** addition manners of fluorescent indicators and influence factors of fluorescence detection sensitivity are summarized. Finally, some critical prospects of fluorescence based corrosion detection are proposed.

关键词： Fluorescence Indicator Corrosion detection Metals Coating

Electrical Characteristics of Plasma Plume During Pulse Wave Laser Welding

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Transactions of Tianjin University 2019年第4期25卷 420-428页

作者： Tong Liu Lijun Yang Shengbin Zhao Yiming Huang school of Materials science and engineering Tianjin University

To detect the real-time plasma plume during pulse wave Nd:YAG laser welding, experimental studies were conducted based on asynchronous signal acquisition system. The electrical signals of the laser-induced plasma plume were obtained by a passive acquisition system. The plume was directly observed and recorded using synchronous high-speed camera. The results showed that the waveform of the signals was in accordance with the periodical laser power. The signals decreased after the laser was turned on and fl uctuated relatively steadily on the stable stage and then increased to 0 V after the laser beam was turned off . The decreasing time of the electrical signals was roughly 1.0 ms, and it decreased with the increasing peak power. However, the average power had insignifi cant eff ect on the signal decreasing time.

关键词： Pulse wave Laser welding Plasma plume Electrical signal Passive probe

A hybrid strategy to control uncertain nonlinear chaotic system

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Chinese Physics B 2017年第10期26卷 89-97页

作者：隋永波何怡刚于文新李燕 The school of Electrical and Automation engineering Hefei University of Technology school of Information and Electrical engineering Hunan University of science and Technology College of Electrical and Information engineering Hunan University

In this paper, a new method, based on firefly algorithm （FA） and extreme learning machine （ELM）, is proposed to control chaos in nonlinear system. ELM is an efficient predicted and classified tool, and can match and fit nonlinear systems efficiently. Hence, mathematical model of uncertain nonlinear system is obtained indirectly. For higher fitting accuracy, a novel swarm intelligence algorithm FA is drawn in our proposed way. The main advantage is that our proposed method can remove the limitation that mathematical model must be known clearly and can be applied to unknown nonlinear chaotic system.

关键词： chaos firefly algorithm extreme learning machine

Leader-follower Consensus of Upper-triangular Nonlinear Multi-agent Systems

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IEEE/CAA Journal of Automatica Sinica 2014年第2期1卷 210-217页

作者： Chenghui Zhang Le Chang Xianfu Zhang school of Control science and engineering Shandong University

This paper is concerned with the leader-follower consensus problem by using both state and output feedback for a class of nonlinear multi-agent systems. The agents considered here are all identical upper-triangular nonlinear systems which satisfy the Lipschitz growth condition. First, it is shown that the leader-follower consensus problem is equivalent to the control design problem of a high-dimensional multi-variable ***, by introducing an appropriate state transformation, the control design problem can be converted into the problem of finding a constant parameter, which can be obtained by solving the Lyapunov equation and estimating the nonlinear terms of the given system. At last, an example is given to verify effectiveness of the proposed consensus algorithms.

关键词： Multi-agent systems Protocols Topology Observers Nonlinear systems

Advanced multiple response surface method of sensitivity analysis for turbine blisk reliability with multi-physics coupling

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Chinese Journal of Aeronautics 2016年第4期29卷 962-971页

作者： Zhang Chunyi Song Lukai Fei Chengwei Lu Cheng Xie Yongmei school of Mechanical and Power engineering Harbin University of Science and Technology school of Energy and Power engineering Beihang University Department of Mechanical engineering The Hong Kong Polytechnic University

To reasonably implement the reliability analysis and describe the significance of influencing parameters for the multi-failure modes of turbine blisk, advanced multiple response surface method (AMRSM) was proposed for multi-failure mode sensitivity analysis for reliability. The mathematical model of AMRSM was established and the basic principle of multi-failure mode sensitivity analysis for reliability with AMRSM was given. The important parameters of turbine blisk failures are obtained by the multi-failure mode sensitivity analysis of turbine blisk. Through the reliability sensitivity analyses of multiple failure modes (deformation, stress and strain) with the proposed method considering fluid-thermal-solid interaction, it is shown that the comprehensive reliability of turbine blisk is 0.9931 when the allowable deformation, stress and strain are 3.7 x 10(-3) m, 1.0023 x 10(9) Pa and 1.05 x 10(-2) m/m, respectively; the main impact factors of turbine blisk failure are gas velocity, gas temperature and rotational speed. As demonstrated in the comparison of methods (Monte Carlo (MC) method, traditional response surface method (RSM), multiple response surface method (MRSM) and AMRSM), the proposed AMRSM improves computational efficiency with acceptable computational accuracy. The efforts of this study provide the AMRSM with high precision and efficiency for multi-failure mode reliability analysis, and offer a useful insight for the reliability optimization design of multi-failure mode structure. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

关键词： Advanced multiple response surface method Artificial neural network Intelligent algorithm Multi-failure mode Reliability analysis Turbine blisk

State and Output Feedback Finite-time Guaranteed Cost Control of Linear It Stochastic Systems

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Journal of Systems science & Complexity 2015年第4期28卷 813-829页

作者： YAN Zhiguo ZHANG Guoshan WANG Jiankui ZHANG Weihai school of Electrical engineering and Automation Qilu University of Technology school of Electrical engineering and Automation Tianjin University College of Electrical engineering and Automation Shandong University of Science and Technology

The problem of guaranteed cost control based on finite-time stability for stochastic system is first investigated in this *** motivation of solving this problem arises from an observation that finite/infinite-horizon guaranteed cost control does not consider the transient performance of the closed-loop system,but guaranteed cost control based on finite-time stability involves this practical *** order to explain this problem explicitly,a concept of the stochastic finite-time guaranteed cost control is introduced,and then some new sufficient conditions for the existence of state and output feedback finite-time guaranteed cost controllers are derived,which guarantee finite-time stochastic stability of closed-loop systems and an upper bound of a quadratic cost ***,this problem is reduced to a convex optimization problem with matrix inequality constraints and a new solving algorithm is ***,an example is given to illustrate the effectiveness of the proposed method.

关键词： Finite-time stability guaranteed cost control matrix inequalities stochastic systems.

Dual-wavelength Bi2Se3-based passively Q-switching Nd3+-doped glass all-fiber laser

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Chinese Optics Letters 2018年第2期16卷 103-107页

作者： Xiaofeng Rong Saiyu Luo Wensong Li Shuisen Jiang Xigun Yah Xiaofeng Guan Zhiyong Zhou Bin Xu Nan Chen Degui Wang Huiying Xu Zhiping Cai Department of Electronic engineering School of Information Science and EngineeringXiamen UniversityXiamen 361005China school of Physics and Electronic science Guizhou Normal UniversityGuiyang 550001China

We demonstrate a dual-wavelength passively Q-switched Nd^（3＋）-doped glass fiber laser using a few-layer topological insulator Bi2Se3 as a saturable absorber（SA） for the first time, to the best of our knowledge. The laser resonator is a simple and compact linear cavity using two fiber end-facet mirrors. The SA is fabricated by Bi2Se3/polyvinyl alcohol composite film. By inserting the SA into the laser cavity, a stable Q-switching operation is achieved with the shortest pulse width and maximum pulse repetition rate of 601 ns and 205.2 kHz,respectively. The maximum average output power and maximum pulse energy obtained are about 6.6 mW and 38.8 nJ, respectively.

关键词： length doped glass all-fiber laser Dual-wavelength Bi2Se3-based passively Q-switching Nd SA Bi

Effect of Middle-frequency Electromagnetic Field on the Semi-continuous Casting for ZK60 Billets

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Journal of Wuhan University of Technology(Materials science) 2010年第3期25卷 449-453页

作者：任政张兴国 school of Materials science and engineering Dalian University of Technology

The semi-continuous casting of ZK60 magnesium alloy under different middle frequency electromagnetic field conditions was *** of middle frequency electromagnetic field on microstructure,precipitations and tensile properties are *** results show that the microstructures of ZK60 magnesium alloy are refined and distribution uniformity of precipitations is observed after applying the middle frequency electromagnetic *** the tensile properties of the billets produced by middle frequency electromagnetic field are increased.

关键词： middle frequency electromagnetic field semi-continuous casting ZK60