翻译原文(公交车投币监测系统的研究)(1)

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1、ApplicationofElectromagneticMaterialSensorBostonRonaldW.GamacheOElectromagneticMaterialPropertiesSensorAbstractRecentresearchconductedbytheauthorhasshownthatelectromagneticsensorscanbeutilizedtodetermineselectedpropertiesofheterogeneousmaterialmixturescontainingwaterbyobservingthemanifestation

2、sofsurfacepolarizationeffectsthatoccurintheradiofrequencyportionoftheelectromagneticspectrum.Forexample,thedensityandwatercontentofengineeringsoilscanbedeterminednon-invasivelyusingthismethod.Especiallychallengingisthedesignofelectromagneticsensorsthatdonotrequirepenetratingprobestoperformthem

3、easurement.Probedeploymentistimeconsumingandsubjecttotechnicalandoperatorerrorsources.Surfacemeasuringsensors,however,maybephysicallylargeandsubjecttomaterialsurfaceeffects(flatnessandroughness).Inaddition,sensorsthatmeasurefromthesurfacesamplethemeasurementvolumenon-uniformly,withthegreatests

4、ensitivitybeingnearthesurface.Therefore,ifthemeasuredpropertyexhibitsasignificantvariationwithdepth,thesensormustmeasurethisvariationinordertoproduceanaccuratemeasurement.Finally,thelargesizeofthesensors,combinedwiththerequiredoperatingfrequencyrange,mayintroduceundesirableresonanceandtransmis

5、sionlineeffectsthatcanrenderthesensornon-functionalincriticalfrequencyranges.Priortotheavailabilityofmultiphysicsfiniteelement(FEM)orfinitedifference(FD)modelingtoolsandsufficientdesktopcomputerhorsepower,sensordesignwasconductedusingad-hoctrialanderrormethods.Costofdevelopmentandtimetomarketw

6、erehighandresultsweregenerallyfarfromoptimum.Toproperlymodelanelectromagneticsensorforsoildensitymeasurement,fullelectromagneticmodespluscoupledheattransferwererequired.Asthesensorgeometrygenerallyconsistsofelementswithverylargeaspectratios,challengesexistwithcreationofstablemeshesandsolutions

7、.Inthispaper,acasestudyintheuseofamulti-physicsFEMmodelingprogram(COMSOLMultiphysics)todesignandoptimizeasensorformeasuringthedensityofanengineeringmaterialwillbedescribed.Issuessuchasdepthofmeasurement,sensitivity,andsensorelectricalch