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passivity breakdown on 436 ferritic stainless steel in solutions containing chloride

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Journal of Materials Science & Technology 2019年第4期35卷 637-643页

作者： Jiaming Wang Shengsheng Qian Yanhui Li Digby D.Macdonald Yiming Jiang Jin Li Department of Materials Science Fudan University Department of Materials Science and Engineering University of California at Berkeley Key Laboratory of Thermo-Fluid Science and Engineering of MOE Xi'an Jiaotong University

passivity breakdown on 436 ferritic stainless steel(FSS) has been investigated in solutions containing different concentrations of chloride at 25?C and interpreted in terms of the point defect model(PDM). The measured near-normal distributions of passivity breakdown potentials for 436 FSS under experimental conditions are in good agreement with the calculated results according to the PDM. The linear dependence of breakdown potential on the square root of potential scanning rate, which was described by the PDM,provides the estimation of the critical concentration of condensed vacancies at the metal/film interface,which leads to the passivity breakdown. This value is in good agreement with that calculated from the microstructure properties of the alloy substrate and the barrier layer of the passive film. This study demonstrates the validity of the PDM in describing the passivity breakdown on 436 FSS in NaCl solutions.

关键词： 436 ferrite stainless steel passivity breakdown Point defect model Chloride ions

Stability and passivity Analysis for Lur'e Singular Systems with Markovian Switching

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International Journal of Automation and computing 2013年第1期10卷 79-84页

作者： Ping-Fang Zhou Yue-Ying Wang Quan-Bao Wang Ji-An Chen Deng-Ping Duan School of Aeronautics and Astronautics Shanghai Jiao Tong University

This paper is concerned with the stochastic stability and passivity analysis for a class of Lur’e singular systems with time-varying delay and Markovian switching. By using the free-weighting matrices approach, a delay-dependent stability criterion, which guarantees that the system is stochastically stable and robustly passive, is derived in terms of linear matrix inequality （LMI）. Two numerical examples are provided to illustrate the effectiveness of the proposed method. 更多还原

关键词： Lur’e singular time-delay systems Markovian jump systems delay-dependent passivity linear matrix inequality （LMI）

Improved results on passivity analysis of discrete-time stochastic neural networks with time-varying delay

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中南大学学报（自然科学版） 2009年第S1期40卷 63-67页

作者：于建江张侃健费树岷 School of Information Science and Technology Yancheng Teachers University School of Automation Southeast University

The problem of passivity analysis for a class of discrete-time stochastic neural networks (DSNNs) with time-varying interval delay was investigated. The delay-dependent sufficient criteria were derived in terms of linear matrix inequalities (LMIs). The results are shown to be generalization of some previous results and are less conservative than the existing works. Meanwhile, the computational complexity of the obtained stability conditions is reduced because less variables are involved. A numerical example is given to show the effectiveness and the benefits of the proposed method.

关键词： passivity discrete-time stochastic neural networks (DSNNs) interval delay linear matrix inequalities (LMIs)

Formation control for nonholonomic agents using passivity techniques

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Applied Mathematics and Mechanics(English Edition) 2010年第1期31卷 27-36页

作者：吴凡耿志勇 State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Aerospace EngineeringPeking University

This paper studies the problem of the formation control for the multiple nonholonomic agents on a plane. A dynamic feedback linearization method is used to transform the dynamical model of each agent into two third-order integrator chains. A decentralized formation control law with the inter-agent damping .injection is derived. The asymptotical stability of the overall system is proven using the Lyapunov method. The simulation of the formation maneuver of a planar vehicle shows the effectiveness of the proposed method.

关键词： nonholonomic agents formation full-state linearization passivity

On passivity of state delayed stochastic jump systems

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Journal of Systems Engineering and Electronics 2005年第2期16卷 394-397页

作者： LiuFei InstituteofAutomation SoutherYangtzeUniversityWuxi214036P.R.China

Based on the definition of passivity extended from deterministic system, the sufficient condition on passivity of stochastic jump system is given against unknown state time delay. By means of memoryless state feedback, a class of state delayed stochastic jump systems may be led to passive. The feedback controllers are mode-dependent and can be constructed in terms of the solutions of a set of coupled linear matrix inequalities. A numerical example illustrates the results.

关键词： stochastic jump systems passivity time delay linear matrix inequality.

Robust Damping Method For Voltage Source Converter with LCL-type Filter Under Weak Grid Conditions

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CSEE Journal of Power and Energy Systems 2022年第5期8卷 1428-1437页

作者： Huaiyuan Liu Dianguo Xu Lei Li Qiang Gao School of Electrical Engineering&Automation Harbin Institute of TechnologyHarbinChina

Power electronic converters under weak grid conditions may trigger new dynamic stability problems.Even though massive internal and external damping methods have been investigated,their system costs and robustness have not been solved in an effective way.This paper first proposes a sensorless active damping method based on the grid current feedback filter.The mid-frequency non-passive region of converters can be reduced effectively,thus system stability improvement in weak grids can be realized.Then this paper analyzes the feedback filter which may bring about additional non-passive regions in high frequency.What’s more,it has a poor robustness.The residual mid-frequency non-passive region can be enlarged under converter parameter variations.Furthermore,this paper proposes a hybrid active damping method.The grid voltage is fed forward through a low pass filter.The robustness against parameter variation is greatly improved and the non-passive region in high frequency is also totally eliminated.In order to further improve the system robustness in high frequency,a simple passive damping is also added.The damping resistor is designed small to reduce the damping loss.The simulation and experimental results prove that the proposed sensorless method can realize robust damping in an economic way.

关键词： Impedance based method LCL filter passivity robust damping

Pitting corrosion behavior and corrosion protection performance of cold sprayed double layered noble barrier coating on magnesium-based alloy in chloride containing solutions

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Journal of Magnesium and Alloys 2023年第9期11卷 3099-3119页

作者： M.Daroonparvar A.Helmer A.M.Ralls M.U.Farooq Khan A.K.Kasar R.K.Gupta M.Misra S.Shao P.L.Menezes N.Shamsaei National Center for Additive Manufacturing Excellence Auburn UniversityAuburnAL 36849USA Department of Mechanical Engineering Auburn UniversityAuburnAL 36849USA Department of Materials Science and Engineering College of EngineeringNorth Carolina State University911 Partners WayRaleighNC 27695USA Department of Mechanical Engineering University of Nevada RenoRenoNV 89501USA Department of Nuclear Engineering and Radiological Sciences University of MichiganAnn ArborMI 48105 USA Department of Chemical and Materials Engineering University of Nevada RenoNV 89501USA

Nitrogen processed, cold sprayed commercially pure(CP)-Al coatings on Mg-based alloys mostly lack acceptable hardness, wear resistance and most importantly are highly susceptible to localized corrosion in chloride containing solutions. In this research, commercially pure α-Ti top coating having good pitting potential(~1293 mV_(SCE)), high microhardness(HV_(0.025): 263.03) and low wear rate was applied on a CP-Al coated Mg-based alloy using high pressure cold spray technology. Potentiodynamic polarization(PDP) curves indicated that the probability of transition from metastable pits to the stable pits for cold spayed(CS) Al coating is considerably higher compared to that with the CS Ti top coating(for Ti/Al/Mg system). In addition, CS Ti top coating was in the passivation region in most pH ranges even after 48 h immersion in 3.5 wt% NaCl solution. The stored energy in the CS Ti top coating(as a passive metal) was presumed to be responsible for the easy passivation. Immersion tests indicated no obvious pits formation on the intact CS Ti top coating surface and revealed effective corrosion protection performance of the CS double layered noble barrier coatings on Mg alloys in 3.5 wt% NaCl solution even after 264 h.

关键词： Ti coating Mg alloys Localized corrosion passivity Dislocation density Crystallite size

ENHANCED passivity OF GUILLOTINED ALUMINIUM IN Na_2SiO_3 SOLUTION BY GEL FORMATION

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Acta Metallurgica Sinica(English Letters) 1997年第1期10卷 1-9页

作者： G.T.Burstein

The passivity of guillotined aluminium electrode is enhanced in alkaline electrolytes by SiO32-. It is proposed that the formation of a complete aluminosilicate gel is responsible for this phenomenon. Dissolution of the metal proceeds via the existing film and the dissolution product reacts with SiO_3~2- ions to form the gel. Under galvanostatic polarisation, significant amount of the gel is formed when the applied anodic i > 10mA cm-2. This gel layer can then be transformed into barrier-type of oxide film, thus contributing to the initial stage of the high voltage anodisation.

关键词： passivity repassivation guillotined aluminium silicate dissolution

Retrospect and prospect on integration of gain and phase for feedback stability analysis

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Control Theory and Technology 2022年第4期20卷 555-558页

作者： Di Zhao Li Qiu Department of Control Science and Engineering&Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 201804China Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Guangzhou HKUST Fok Ying Tung Research Insititute Nansha DistrictGuangzhou 511458GuangdongChina

In this paper,we review existing approaches to integrating small gain and small phase analysis for feedback stability of dynamical systems,and give a brief outlook for possible future directions in exploring this topic.Small gain analysis has been very successful and popular in control theory since 1960s,while the small phase analysis for multiple-input-multiple-output systems has not been well understood until recently and is now gradually taking shape.Nevertheless,there have been attempts to analyzing feedback stability via the integration of gain and phase information over decades,including the combination of small gain with positive realness as well as that with negative imaginariness.Such combinations can be subsumed into a recently proposed framework for gain-phase integration,which brings in new geometrical methods and also sheds new lights on several future directions.

关键词： Small gain Small phase passivity Positive real Negative imaginary Davis-Wielandt shell