基本信息
| 标准名称： | 出口香蕉检验规程 |
| 中标分类： |
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| 替代情况： | 转化为SN/T 0885-2000 |
| 发布日期： | |
| 实施日期： | 2002-05-01 |
| 首发日期： | |
| 作废日期： | |
| 出版日期： | |
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引用标准
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【英文标准名称】:StandardTestMethodforMeasuringtheElectromagneticShieldingEffectivenessofPlanarMaterials
【原文标准名称】:平面材料的电磁屏蔽效果测定的标准试验方法
【标准号】:ASTMD4935-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D09.12
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:electromagneticshielding;farfield;nearfield;shielding;shieldingeffectiveness(SE);Semi-conductingmaterials;Shieldingeffectiveness;Ceramicmaterials--electrical/electronicdevices;Composites--conducting/nonconductingmaterials;Conductanc
【摘要】:ThistestmethodappliestothemeasurementofSEofplanarmaterialsundernormalincidence,far-field,plane-waveconditions(EandHtangentialtothesurfaceofthematerial).TheuncertaintyofthemeasuredSEvaluesisafunctionofmaterial,mismatchesthroughoutthetransmissionlinepath,dynamicrangeofthemeasurementsystem,andtheaccuracyoftheancillaryequipment.AnuncertaintyanalysisisgiveninAppendixX1toillustratetheuncertaintythatmaybeachievedbyanexperiencedoperatorusinggoodequipment.Deviationsfromtheprocedureinthistestmethodwillincreasethisuncertainty.Approximatenear-fieldvaluesofSEmaybecalculatedforbothEorHsourcesbyusingmeasuredvaluesoffar-fieldSE.AprogrammaybegeneratedfromthesourcecodeinAppendixX2thatissuitableforuseonapersonalcomputer.ThistestmethodmeasuresthenetSEcausedbyreflectionandabsorption.Separatemeasurementofreflectedandabsorbedpowermaybeaccomplishedbytheadditionofacalibratedbidirectionalcouplertotheinputoftheholder.1.1Thistestmethodprovidesaprocedureformeasuringtheelectromagnetic(EM)shieldingeffectiveness(SE)ofaplanarmaterialforaplane,far-fieldEMwave.Fromthemeasureddata,near-fieldSEvaluesmaybecalculatedformagnetic(H)sourcesforelectricallythinspecimens.,Electric(E)fieldSEvaluesmayalsobecalculatedfromthissamefar-fielddata,buttheirvalidityandapplicabilityhavenotbeenestablished.1.2Themeasurementmethodisvalidoverafrequencyrangeof30MHzto1.5GHz.Theselimitsarenotexact,butarebasedondecreasingdisplacementcurrentasaresultofdecreasedcapacitivecouplingatlowerfrequenciesandonovermoding(excitationofmodesotherthanthetransverseelectromagneticmode(TEM))athigherfrequenciesforthesizeofspecimenholderdescribedinthistestmethod.Anynumberofdiscretefrequenciesmaybeselectedwithinthisrange.Forelectricallythin,isotropicmaterialswithfrequencyindependentelectricalpropertiesofconductivity,permittivity,andpermeability,measurementsmaybeneededatonlyafewfrequenciesasthefar-fieldSEvalueswillbeindependentoffrequency.Ifthematerialisnotelectricallythinorifanyoftheparametersvarywithfrequency,measurementsshouldbemadeatmanyfrequencieswithinthebandofinterest.1.3Thistestmethodisnotapplicabletocablesorconnectors.1.4Units8212;ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:K04
【国际标准分类号】:
【页数】:10P.;A4
【正文语种】:英语