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Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVArI m.r.HOmAEINEZHAD Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(Amm) nonlinear motion analysis

Biderivations of Hom-Lie Algebras and Superalgebras

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Acta mathematica Sinica,English Series 2024年第10期40卷 2337-2358页

作者： la mei YUAN Jia Xin LI School of mathematics Harbin Institute of Technology

On Hom-Lie algebras and superalgebras, we introduce the notions of biderivations and linear commuting maps, and compute them for some typical Hom-Lie algebras and superalgebras,including the q-deformed W(2, 2) algebra... 详细信息

关键词： 17A30 17A60 17B05 17B60 17B70 biderivations Hom-Lie algebras linear commuting maps q-deformed W(2 2) algebra q-deformed Witt algebra q-deformed Witt superalgebra

review of Networked microgrid Protection:Architectures,Challenges,Solutions,and Future Trends

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 448-467页

作者： Jorge de la Cruz Ying Wu John E.Candelo-Becerra Juan C.Vasquez Josep m.Guerrero Center for research on microgrids(CrOm) Department of Energy TechnologyAalborg University9220 AalborgDenmark Facultad de minas Departamento de Energia Eléctrica y AutomaticaUniversidad Nacional de ColombiaSede MedellinCarrera 80 No.65-223RobledoMedellin 050041Colombia. Center for research on microgrids at UPC(UPC CrOm) Department of Electronic EngineeringTechnical University of Catalonia(UPC)08019 Barcelona Spain ICrEA Pg.Lluis Companys 2308010 BarcelonaSpain Center for research on microgrids at AAU(AAU CrOm) AAU EnergyAalborg University(AAU)9220 Aalborg EastDenmark

Design and selection of advanced protection schemes have become essential for reliable and secure operation of networked *** protection schemes that allow correct operation of microgrids have been proposed for individual systems in different topologies and ***,protection schemes for networked microgrids are still in devel-opment,and further research is required to design and operate advanced protection in interconnected *** of these microgrids in different nodes with various intercon-nection technologies increases fault occurrence and complicates protection *** paper aims to point out challenges in developing protection for networked microgrids,potential solutions,and research areas that need to be addressed for their ***,this article presents a systematic analysis of different microgrid clusters proposed since 2016,including several architectures of networked microgrids,operation modes,components,and utilization of renewable sources,which have not been widely explored in previous review ***,the paper presents a discussion on protection systems currently available for microgrid clusters,current challenges,and solutions that have been proposed for these ***,it discusses the trend of protection schemes in networked microgrids and presents some conclusions related to ***—Adaptive eprotection,microgrid cluster,microgrid,multiple microgrid,networked microgrid,real-time simulation,smart grid.

关键词： Adaptive eprotection microgrid cluster microgrid multiple microgrid networked microgrid real-time simulation smart grid

Truly optimal semi-active damping to control free vibration of a single degree of freedom system

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Theoretical & Applied mechanics Letters 2024年第2期14卷 142-145页

作者： Viet Duc la Ngoc Tuan Nguyen Institute of mechanics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

This paper studies a single degree of freedom system under free vibration and controlled by a general semiactive damping.A general integral of squared error is considered as the performance index.A one-time switching damping controller is proposed and *** pontryagin maximum principle is used to prove that no other form of semi-active damping can provide the better performance than the proposed one-time switching damping.

关键词： Analytical optimization Quadratic integral Lyapunov equation Pontryagin maximum principle

rice Variety Classification Based on Optimized Near-Infrared Spectral Classification model

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rice science 2024年第1期31卷 6-9,I0009-I0012页

作者： YANG sen WANG Zhenmin ZHANG Houqing SONG Wenlong College of Computer and Control Engineering Northeast Forestry UniversityHarbin 150040China The 49th research Institute of China Electronics Technology Group Corporation Harbin 150000China

Accurate classification of rice variety is essential to ensure the brand value of high-quality rice *** the impact of sample state on modeling optimization algorithms,rice samples after grinding and sealing were *** enhance the accuracy of rice variety classification,we introduced a spectral characteristic wavelength selection method based on adaptive sliding window permutation entropy(ASW-PE).

关键词： sealing Infrared grinding

Pile foundation in alternate layered liquefiable and non-liquefiable soil deposits subjected to earthquake loading

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 359-376页

作者： Praveen Huded m Suresh r Dash LEA Associates South East Asia Pvt.Ltd. New Delhi 110044India Indian Institute of Technology Bhubaneswar Khurda 752050India

Pile foundations are still the preferred foundation system for high-rise structures in earthquake-prone *** foundations have experienced failures in past earthquakes due to *** on pile foundations in liquefiable soils has primarily focused on the pile foundation behavior in two or three-layered soil ***,in natural occurrence,it may occur in alternative layers of liquefiable and non-liquefiable ***,the experimental and/or numerical studies on the layered effect on pile foundations have not been widely addressed in the *** of the design codes across the world do not explicitly mention the effect of sandwiched non-liquefiable soil layers on the pile *** the present study,the behavior of an end-bearing pile in layered liquefiable and non-liquefiable soil deposit is studied *** study found that the kinematic bending moment is higher and governs the design when the effect of the sandwiched non-liquefied layer is considered in the analysis as opposed to when its effect is ***,ignoring the effect of the sandwiched non-liquefied layer in a liquefiable soil deposit might be a nonconservative design approach.

关键词： pile foundation liquefaction alternately layered soil fixity effect layered effect

Charge transfer complex enabled photoreduction of ether phosphonium salts for the selective oxyalkylation of enamides

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Chinese Chemical Letters 2024年第2期35卷 411-414页

作者： sen Qiao Kunquan Chen Qiang Liu Zhixiang Wang Xiangyu Chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing 100049China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou 256606China

A charge transfer complex(CTC)-enabled photoreduction of ether phosphonium salts for the generation of oxyalkyl radicals was *** photoreduction provides a convenient method to achieve selective oxyalkylation of enamid... 详细信息

关键词： Enamides Phosphonium salts Ethers Charge transfer complex Visible light

Preparation of TiO_(2) Nano-Flower Coating on Ti Substrates with Good Physical Sterilization Effect and Biocompatibility

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Acta metallurgica Sinica(English Letters) 2024年第9期37卷 1581-1589页

作者： ruoyu Di Yonghua Sun runhua Yao sen Pei Xiaohong Yao ruiqiang Hang Shanxi Key laboratory of Biomedical metal materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan030024China College of Safety and Emergency management Engineering Taiyuan University of TechnologyTaiyuan030024China

We report a facile solution method to form titanium oxide(TiO_(2))nano-flower structure on the titanium(Ti)substrates for realizing good physical sterilization and *** first prepare TiO_(2) nanotubes(NT)with a diameter of about 80-100 nm and a length of about 5μm on Ti substrates by anodization,which is utilized as ***,we employ immersion treatment in different concentrations of phosphoric acid solution at 75℃ for 5 h to realize the transformation from TiO_(2) NT to TiO_(2) nano-flower *** addition,we studied the effects of phosphoric acid concentration(1 wt%,2.5 wt%,5 wt% and 10 wt%)on the TiO_(2) nano-flower structure,and the antibacterial properties and biocompatibility of the TiO_(2) nano-flower *** results show that TiO_(2) nano-flower structure become larger and thicker with the increase in the phosphoric acid concentration,and the thickness of the coating can reach 6.88μ***,the TiO_(2) nano-flower structure shows good physical sterilization effect,especially for the TiO_(2) nano-flower structure formed in 10 wt%H^(3)PO_(4) solution,the antibacterial rate can reach 95%.In addition,the TiO_(2) nano-flower structure have no toxicity to the osteoblasts and support cell growth.

关键词： Anodization Biocompatibility Physical sterilization TiO_(2)nano-flower

Kinematic analysis of flexible bipedal robotic systems

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Applied mathematics and mechanics(English Edition) 2024年第5期45卷 795-818页

作者： r.FAZEL A.m.SHAFEI S.r.NEKOO Department of mechanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of *** most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational *** extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned *** overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue *** solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient