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Optimal Six Vector Switching Pattern in Matrix Converters for Reducing Harmonics and Switching Loss

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CSEE Journal of Power and Energy Systems 2023年第1期9卷 135-144页

作者： pengfei yao Xiaohua Jiang Department of electrical engineering Tsinghua UniversityBeijing 100084China

This paper analyses harmonic distortion caused by the narrow pulse problem in matrix converters,and presents an improved switching pattern that is based on the basic five vector switching *** limited switching frequencies,the improved pattern solves the narrow pulse problem by applying an additional zero vector and adjusting the sequence of the four active vectors at the same time to minimize the switching *** results show that in the six vector switching pattern,a)the low-frequency harmonics caused by the narrow pulse problem are greatly reduced;b)the average switching frequency is reduced compared with the five vector pattern;c)the sampling frequency harmonics are apparently attenuated though a little 1/2 and 3/2 sampling frequency harmonics are produced;d)the THD of the output current is improved to the same level of the three zero vector switching pattern(TZVSP);e)the proposed switching pattern has benefits in both normal and unbalance input voltage *** results on a matrix converter platform,verify the benefits of the six vector switching *** dynamic,lower harmonics and lower losses can be achieved by using the proposed six vector switching pattern.

关键词： Harmonics matrix converters modulation switching pattern

Energy Decay for the Cauchy Problem of the Linear Wave Equation of Variable Coeffcients with Dissipation

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Chinese Annals of Mathematics,Series B 2010年第1期31卷 59-70页

作者： pengfei yao Key Laboratory of Control and Systems Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Decay of the energy for the Cauchy problem of the wave equation of variable coefficients with a dissipation is considered. It is shown that whether a dissipation can be localized near infinity depends on the curvature properties of a Riemannian metric given by the variable coefficients. In particular, some criteria on curvature of the Riemannian manifold for a dissipation to be localized are given.

关键词： Wave equation Riemannian metric Localized dissipation near infinity

GENERAL DECAY RATE ESTIMATES FOR VISCOELASTIC WAVE EQUATION WITH VARIABLE COEFFICIENTS

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Journal of Systems Science & Complexity 2014年第5期27卷 836-852页

作者： CAO Xiaomin yao pengfei School of Mathematical Sciences Shanxi University Key Laboratory of Control and Systems Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of Sciences

The authors study decay properties of solutions for a viscoelastic wave equation with variable coefficients and a nonlinear boundary damping by the differential geometric approach.

关键词： Energy decay nonlinear boundary damping Riemannian metric viscoelastic wave equation

Weighted L^2-Estimates of Solutions for Damped Wave Equations with Variable Coefficients

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Journal of Systems Science & Complexity 2017年第6期30卷 1270-1292页

作者： yao pengfei ZHANG Zhife Key Laboratory of Control and System Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Department of Mathematics and Statistics Huazhong University of Science and Technology

The authors establish weighted L^2-estimates of solutions for the damped wave equations with variable coefficients utt-div A(x)▽u + au_t = 0 in IR^nunder the assumption a(x) ≥ a_0[1 + ρ(x)]^(-l),where a_0 > 0, l < 1, ρ(x) is the distance function of the metric g = A^(-1)(x) on IR^n. The authors show that these weighted L^2-estimates are closely related to the geometrical properties of the metric g = A^(-1)(x).

关键词： Distance function of a metric Riemannian metric wave equation with variable coefficients weighted L^2-estimate

Decay Rates of the Hyperbolic Equation in an Exterior Domain with Half-Linear and Nonlinear Boundary Dissipations

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Journal of Systems Science & Complexity 2016年第3期29卷 657-680页

作者： LIU Yuxiang LI Jing yao pengfei Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences Shanxi University

This paper considers the energy decay of the wave equation with variable coefficients in an exterior *** damping is put on partly the boundary and partly on the interior of the *** energy decay results are established... 详细信息

关键词： Energy decay exterior domain hyperbolic equation Riemannian geometry method variable coefficients.

GLOBAL SMOOTH SOLUTIONS FOR SEMILINEAR SCHRDINGER EQUATIONS WITH BOUNDARY FEEDBACK ON 2-DIMENSIONAL RIEMANNIAN MANIFOLDS

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Journal of Systems Science & Complexity 2009年第4期22卷 749-776页

作者： Li DENG pengfei yao Key Laboratory of Control and Systems Institute of Systems Science Academy of Mathematics and SystemsScience Chinese Academy of Sciences Beijing 100190 China Graduate School of the Chinese Academy ofSciences Beijing 100049 China Key Laboratory of Control and Systems Institute of Systems Science Academy of Mathematics and SystemsScience Beijing 100190 China

This paper considers the existence of global smooth solutions of semilinear schrSdinger equation with a boundary feedback on 2-dimensional Riemannian manifolds when initial data are small. The authors show that the existence of global solutions depends not only on the boundary feedback, but also on a Riemannian metric, given by the coefficient of the principle part and the original metric of the manifold. In particular, the authers prove that the energy of the system decays exponentially.

关键词： Boundary feedback energy decay Riemannian metric semilinear schr6dinger equation.

Exact controllability of a structural acoustic system with variable coefficient and curved wall 36

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Exact controllability of a structural acoustic system with v...

Pneumatic bio-soft robot module:Structure,elongation and experiment

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作者： Fengyan Yang pengfei yao Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of Sciences

ISBN: (纸本)9781538629185

This paper is concerned with the exact controllability of a structural acoustic system with two controls, which consists of an interior acoustic wave equation with variable coefficient and a coupled Kirchoff plate with a curved middle surface. We use the Riemannian geometrical approach and the multiplier technique to prove the corresponding observability inequality. And the exact controllability of this system is finally established under verifiable assumptions on the geometry of the interior domain and the interface.

关键词： exact controllability structural acoustic system variable coefficient curved wall Riemannian geometry

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International Journal of Agricultural and Biological Engineering 2017年第2期10卷 114-122页

作者： Bao Guanjun yao pengfei Xu Zonggui Li Kun Wang Zhiheng Zhang Libin Yang Qinghua College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310014China

Soft robotics,often taking inspirations from biomimetics,is an exciting novel research field and has great capability to work with creatures.A new type of bio-soft robot inspired by elephant trunk and octopus was proposed,which has a promising application in robotic agricultural *** two modularized structures,basal segment and caudal segment,were elaborated in *** both have three side chambers and one central chamber,which are reinforced by springs for better stretch performance in axial direction without radial *** the chambers can act as drivers when inflated with compressed *** importantly,the central chamber was designed for regulating the stiffness of the robot module as needed in *** primary static model for axial elongation was established for the fundamental analysis of the bio-soft robot module’s features,such as iso-force,isobaric and isometric *** and experimental results showed that the motion of the proposed bio-soft module has approximate linearity in iso-force and isobaric conditions,and strict linearity in isometric condition.

关键词： bio-soft robot pneumatic muscle actuator static model harvesting robot

Metal−support interaction in single-atom electrocatalysts:A perspective of metal oxide supports

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eScience 2024年第5期4卷 1-9页

作者： Ce Han Shaoqing Zhang Huimin Zhang Yining Dong pengfei yao Yingnan Du Ping Song Xue Gong Weilin Xu State Key Laboratory of Electroanalytical Chemistry Jilin Province Key Laboratory of Low Carbon Chemical PowerChangchun Institute of Applied ChemistryChinese Academy of Sciences5625 Renmin StreetChangchunJilin 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefeiAnhui 230026China

The discovery of single-atom catalysts(SACs)represents a groundbreaking advancement in the field of catalysis over the past *** the in-depth exploration of relevant structure-activity relationships,the metal−support interaction(MSI)is widely adopted to elucidate variations in electronic structure and coordination configuration of atomic active sites on various kinds of ***,we briefly summarize the metal oxide supports for SACs fabrication,including the distinctive characteristics of metal oxide supports,enlightening advancements in metal oxide support-based SACs(MO-SACs),feasible preparation methods for MO-SACs and effective regulation strategies of MSI effect in *** addition,we present our viewpoints and outlook in this field to stimulate rational design and construction of novel MO-SACs applied in diverse renewable energy devices,while some universal suggestions are sincerely given to provoke thoughtful considerations during the research process.

关键词： Single-atom catalyst Metal oxide Electrocatalysis Metal-support interaction