学科分类
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4 个结果
  • 简介:Anopen-endedcoaxiallinereflectionmethodespeciallysuitableformeas-uringthedielectricpropertiesofbiologicaltissueinvivoisdescribed.Thismethodofferstheadvantageofnotrequiringanyspecialpreparationofthesamplestobemeasuredbutaclosecontactwiththeopenendofacoaxialline.Itis,therefore,veryconvenienttoacquirealargenumberofmeasurementdatainbroadbandrapidly.Themethodmayalsobeusedtomeasurethepropertiesofothersubstances.ThemeasuringsystemconsistsofanetworkanalyzercontrolledbyamicrocomputerandcalibratedbyusingANAproceduretoelimi-hatetheinflunceoferrornetworkintroducedbytheadapter,someconnectors,etc.Inor-dertoreachhigheraccuracy,theiterativemethodisusedtodeterminetheparametersoftheequivalentcircuit.Measurementsofpermeativitiesofsomelivingtissueshavebeenper-formedinthefrequencybandof0.5-2GHz.Comparedwiththeresultsknowninsomepapers,thevalidityofthismethodhasbeenconfirmed.Thedifferenceindielectricproper-tiesbetweenlivinganddeadtissues,andthetissuepermeativites(ε)versusfrequencyanddurationofmeasurementafterdeathhavealsobeenmeasured.

  • 标签: DIELECTRIC property/biological TISSUE open-ended COAXIAL line
  • 简介:Inthispaperthemodernelectron-opticalequipmentisusedtotranslatetheclearimageofspeed-movingbubblesinbubblingliquidonasievetrayintothedigitalinformationstoredincomputer,andthecomputeraidedimage-processingtechniqueisutillizedtomeasurethebubblesizedistributionsandinterfacialareasundervariousoperatingcondtions.Andthedynamicbehaviorofbubblesintrubulentliquidisanalyzedtheoretically;themechnaismofbubbledeformationandbreakageisexploredonthebasisofKolmogorff'sisotropicturbulencehypothesis;themathematicalmodelforpredictingthegas-liquidinterfacialareaisproposed,Thecomparisonbetweenthesimulatedresultsandtheexperimentaldatashowthatthemodelishigherinaccuracy,simpleinformandconvenientinuse.

  • 标签: 气-液界面 蒸馏柱 塔板 气泡大小分布 扰流 计算机辅助图形分析
  • 简介:Inordertoobtainthesolubilitydataofpropylenein2-propanol-watersolutions,gas-liquidequilibrium(GLE)experimentswerecarriedoutat303.15-333.15K,0.27-0.98MPainastaticequilibriumstill.Theoriginalmassratioof2-propanoltowaterwas9∶1,8∶2,7∶3,1∶0,respectively.TheequilibriumdatawerecorrelatedwithanempiricalmodelandtheregressionofmodelparameterswascompletedbyGauss-Newtonnonlinearleastsquare(NLS).Theaveragerelativedeviation(ARD)betweentheexperimentalandcalculatedvalueis1.5700,andthemaximumrelativedeviation(MRD)is4.8200.Inaddition,asimpleapproachthatcorrelatedthemodelparameterswiththesystemcompositionwasalsoprovided.

  • 标签: 丙烯 2-丙醇-水溶液 溶解度 气液平衡 高斯-牛顿非线性最小二乘法
  • 简介:Thestressintensityfactor(SIF)isacriticalparameterassociatedwiththefracturebehaviourofmaterials.Inthispaper,weselectthedisplacementfunctionaroundacracktipastheshapefunctionofthedigitalimagecorrelation(DIC),whichmakesitpossibletodirectlycalculatetheSIFbythecorrelationscheme.Moreover,weuseanon-rectangularsubset,whichcanreducetheinfluenceofplasticdeformationandcrackwidthontheDICmeasurementaccuracy.WemeasuredtheSIFofamodeIcrackinasuper-hardaluminiumalloyspecimentoverifytheperformanceoftheproposedmethod.OurexperimentalresultsshowthataDICwithaspecificshapefunctioncanbeusedtoaccuratelyandefficientlycalculatetheSIF.Furthermore,wealsopresentapracticalapplicationofourproposedmethodfordeterminingtheSIF,crackpropagationangleandcracktipdisplacement.

  • 标签: Digital image CORRELATION (DIC) SHAPE function