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简介：机电的致动器广泛地在许多工业应用被使用。通常有一些限制，在一个设计系统存在。这份报纸建议一个简单方法为机电的致动器设计抑制控制器。控制器合并在内部模型控制利用的想法并且为预兆的控制建模。他们与统一用标准控制系统结构被设计否定反馈。控制器的结构象设计过程一样相对简单。处理机制的输出限制基于许多时间向前走的控制植物行为的预言。机制增加控制控制植物的性能和安全。建议控制器提供的好处在在二个机电的致动器的控制系统执行的真实实验被表明了：一台DC马达和一个electrohydraulic致动器。

简介：Underanappliedvoltage,dielectricelastomers(DEs)produceanactuationstrainthatisnonlinear,partlybecauseofthematerialproperties.Inthisstudy,anexperimentalcharacterizationisconductedtoevaluatehowtheambienttemperatureandpre-stretchaffectedtheactuationperformance.ForDEswithapre-stretchof2×2,anincreaseoftemperaturefrom-10°to80°resultsinavariationintheactuationstrainofmorethan1700%.Lowpre-stretchedDEsaremoresusceptibletotemperaturechange;whilehighlypre-stretchedDEsarerelativelyinsensitivetotemperature,becauseinthiscasetheenergyconversionwasdominatedbymechanicalstretching,ratherthanthermalconduction,duringtheactuation.

简介：Thedynamicalequationsforainertialreciprocatingmachineexcitedbytworotatingeccentricweightswerebuiltbythematrixmethodologyforestablishingdynamicalequationsofdiscretesystems.Amathematicalmodelofelectromechanicalcouplingsystemforthemachinewasformedbycombiningthedynamicalequationswiththestateequationsofthetwomotors.Thecomputersimulationtothemodelwasperformedforseveralvaluesofthedampingcoefficientorthemotorpower,respectively.Thesubstanceoftransientbehaviorofthemachineisunveiledbyanalyzingtheresultsofthecomputersimulation,andnewmethodsarepresentedfordiminishingthetransientamplitudeofthevibratingmachineandimprovingthetransientbehavior.Thereliablemathematicalmodelisprovidedforintelligentcontrolofthetransientbehaviorandengineeringdesignoftheequipment.

简介：One-dimensionalringpowersystemisdiscreditedtoanumberofnodeseachcontainingageneratorwithinternalreactanceandloadbranchofresistanceandreactancewithacertainpowerfactor.Whenadisturbanceoccursatanymachineinthepowersystem,simulativeanalysisisperformedtoverifyhowthevariationofloadpowerfactoraffectingthebehaviorofelectromechanicalwavepropagationbyusingtheMATLABpackage,fromwhichdifferentsituationsarepresentedanddiscussed.Theseresultsshowthetypeofloadhasnoeffectonthebehaviorofelectromechanicalwavepropagation.

简介：Piezoelectricsuperlatticeisapotentialcomponentfornanoelectromechanicalsystems.Duetothestrongnonlocaleffectsuchasflexoelectriceffectatinterfaces,classicalpiezoelectrictheoryisunabletoaccuratelydescribetheelectromechanicalresponseofpiezoelectricsuperlatticeatnanoscalescale.BasedonthepreviousnonlocalthermodynamicstheorywithflexoelectriceffectLiuetal.(2016),thesizedependentelectromechanicalpropertiesofpiezoelectricsuperlatticesmadeofBaTiO_3(BTO)andPbTiO_3(PTO)layersareinvestigatedsystematicallyinthepresentwork.GiantstraingradientisfoundneartheinterfacebetweenBTOandPTOlayers,whichleadstothesignificantenhancementofpolarizationinthesuperlatticeduetotheflexoelectriceffect.ForthepiezoelectricBTO–PTOsuperlatticeswithdifferentunitcellsizes,thethicknessofinterfacewithnontrivialstraingradientisalmostconstant.Theinfluenceofstraingradientattheinterfacebecomessignificantwhenthesizeofsuperlatticedecreases.Asaresult,astrongsizedependenceofelectromechanicalpropertiesispredictedforthepiezoelectricBTO–PTOsuperlattices.Inparticular,forthesuperlatticeswithaspecificthicknessratioofBTOandPTOlayers,thepiezoelectricresponsecanbeseveraltimeslargerthanthatofbulkstructure.Thepresentworkdemonstratesapracticalwaytodesignthepiezoelectricsuperlatticeswithhighpiezoelectriccoefficientbyusingthenonlocaleffectatnanoscale.

简介：Anonlinearfiniteelement(FE)modelbasedondomainswitchingwasproposedtostudytheelectromechanicalbehaviorofferroelectricceramics.TheincrementalFEformulationwasimprovedtoavoidanycalculationinstability.Theproblemsofmeshsensitivityandconvergence,andtheefficiencyoftheproposednonlinearFEtechniquehavebeenassessedtoillustratetheversatilityandpotentialaccuracyofthesaidtechnique.Thenonlinearelectromechanicalbehavior,suchasthehysteresisloopsandbutterflycurves,offerroelectricceramicssubjectedtobothauniformelectricfieldandapointelectricpotentialhasbeenstudiednumerically.Theresultsobtainedareingoodagreementwiththoseofthecorrespondingtheoreticalandexperimentalanalyses.Furthermore,theelectromechanicalcouplingfieldsnear(a)theboundaryofacircularhole,(b)theboundaryofanellipticholeand(c)thetipofacrack,havebeenanalyzedusingtheproposednonlinearfiniteelementmethod(FEM).TheproposednonlinearelectromechanicallycoupledFEMisusefulfortheanalysisofdomainswitching,deformationandfractureofferroelectricceramics.

简介：Theelectromechanicalphasetransitionforadielectricelastomer(DE)tubehasbeendemonstratedinrecentexperiments,whereitisfoundthattheunbulgedphasegraduallychangedintobulgedphase.Previoustheoreticalworksonlystudiedthetransitionprocessunderpressurecontrolcondition,whichisnotconsistentwiththerealexperimentalcondition.Thispaperfocusesonmorecomplexfeaturesoftheelectromechanicalphasetransitionunderinternalpressureofconstantmass.WederivetheequilibriumequationsandtheconditionforcoexistentstatesforaDEtubeunderaninternalpressure,avoltagethroughthethicknessandanaxialforce.Wefindthatundermasscontrolconditionthevoltageneededtomaintainthephasetransitionincreasesastheprocessproceeds.Weanalyzetheentireprocessofelectromechanicalphasetransitionandfindthattheevolutionofconfigurationsisalsodifferentfromthatforpressurecontrolcondition.

简介：Electromechanicalpropertyofap-typesingle-crystalsiliconnanoplateismodelledbyamicroscopicapproachwheretheholequantizationeffectandthespin-orbitcouplingeffectaretakenintoaccount.Thevisibleanisotropicsubbandstructuresarecalculatedbysolvingself-consistentlythestress-dependent6×6k·pSchrdingerequationwiththePoissonequation.Thestrongmixingamongheavy,light,andsplit-offholesisquantitativelyassessed.Theinfluencesofthethicknessandthetemperatureonthepiezoresistivecoefficientarequantitativelyinvestigatedbyusingtheholeconcentrationsandtheeffectivemassesfromthecomplexdispersionstructureofthevalencebandwithandwithoutstresses.Ourresultsshowthatthestressdeterminestheextenttowhichthebandismixed.Theholequantizationeffectincreasesasthethicknessdecreases,andthereforethevalencebandisstronglyreshaped,resultinginthesize-dependentpiezoresistivityofthesiliconnanoplate.Thepiezoresistivecoefficientincreasesalmost4timesasthethicknessreducesfromthebulkto3nm,exhibitingapromisingapplicationinmechanicalsensors.

简介：Thepresentinvestigationofthecrackprobleminpiezoelectricmaterialsisperformedbasedonthenon-localtheory.Aftersomemanipulations,theimpermeablecrack,thepermeablecrack(thecrackgapisfullofNaCIsolution),andthesemi-permeablecrack(thecrackgapisfullofairorsiliconoil)arereducedtoauniformformulationbyassum-ingthenormalelectricdisplacementonthecracksurfacestobeanunknownvariable.Thus,atripleintegralequationwiththeunknownnormalelectricdisplacementisestablished.ByusingtheNewtoniterativemethodandsolvingthetripleinte-gralequation,itisfoundthatthenormalelectricdisplacementonthecracksurfacesisnolongeraconstantasdeterminedbypreviousstudies,rather,itdependsupontheremotecom-binedelectromechanicalloadings.Numericalresultsofthestressesandelectricdisplacementfieldsshowthattherearenosingularitiesatthecracktipssothatthestressesremainfinite.Itisofgreatsignificancethattheconcreteelectricboundaryconditiononthecracksurfacesexertssignificantinfluenceonthenear-tipfieldsandinthiswayplaysanimpor-tantroleinevaluatingthecrackstabilityinthenon-localpiezoelectricmaterials.Morespecifically,theimpermeablecrackmodelalwaysoverestimatesthefinitestressesatthecracktips,whereasthepermeablecrackmodelalwaysunder-estimatesthem.

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简介：ThepiezoelectriccompositescontaininghighlyorientedBaTiO3whiskersasactivephaseandPVDFasmatrixhavebeenpreparedbymicro-holeextrusionandorientationincarriedfibers.ThemorphologyoforientedBaTiO3whiskersandmicrostructureofthecompositeswereobservedbySEM.Asforitselectromechanicalproperties,itisfoundthatthedielectricconstant,piezoelectricconstantandremnantofpolarizationintheBaTiO3whisker-PVDFcompositeareconsiderablyhigherthanthatintheBaTiO3powders-PVDFcomposite,whilethelossfactorsfollowtheoppositetrend.FortheBaTiO3whisker-PVDFcomposite,thevaluesofε,d33andPrparalleltothewhiskerorientation(normalspecimen)aremuchhigherthanthatperpendiculartothewhiskerorientation(parallelspecimen).Thesignificanteffectsoftheconnectivepassagesofactivephaseonelectromechanicalpropertiesofthepiezoelectriccompositeshasalsobeeninvestigated.

简介：在这份报纸，我们在场一三维(3D)在为收音机频率的晶片水平的真空包装技术微机电的系统(RFMEMS)共鸣器，低损失的硅vias在被用来播送RF发信号。Au-Sn焊接结合被采用象电的导体一样提供真空封装。封装帽子的一个RF模型被建立评估包装的寄生效果，它提供3DRFMEMS封装的一个有效设计答案。与建议包装结构，24dB的signal-to-background比率(SBR)被完成，以及共鸣器的优秀因素(Q因素)在包装以后从8000～10400增加。包装共鸣器有线性频率温度(英尺)在在0楨?慰数?之间的一个温度范围特征?牵敶?牡?牰癯摩吗？？

简介：摘要：传统机电管道在施工现场安装时，往往因为施工条件差、场地狭小，导致焊接效果差、效率低、美观度差等问题，影响工程质量。为了改变传统管道施工的诸多缺点，结合装配式建筑与BIM技术的创新趋势，本文总结研究出一套适用于机电装配式模块化施工技术流程并分析了应用中存在的问题。