【英文标准名称】:Classificationofjewellery;groupsoffineness
【原文标准名称】:首饰的等级.纯度
【标准号】:DIN58680T.3-1978
【标准状态】:作废
【国别】:
【发布日期】:
【实施或试行日期】:
【发布单位】:德国标准化学会(DE-DIN)
【起草单位】:
【标准类型】:()
【标准水平】:()
【中文主题词】:
【英文主题词】:
【摘要】:
【中国标准分类号】:
【国际标准分类号】:
【页数】:
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【英文标准名称】:StandardTestMethodforacMagneticPermeabilityofMaterialsUsingSinusoidalCurrent
【原文标准名称】:正弦电流用材料的交流磁导率的标准试验方法
【标准号】:ASTMA772/A772M-2000(2005)
【标准状态】:现行
【国别】:美国
【发布日期】:2000
【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】:A06.01
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:magneticfieldstrength;magneticfluxdensity;magneticinduction;permeability;sinusoidalcurrent;toroidalcore
【摘要】:Thepermeabilitydeterminedbythismethodistheimpedancepermeability.Impedancepermeabilityistheratioofthepeakvalueoffluxdensity(Bmax)totheassumedpeakmagneticfieldstrength(Hz)withoutregardtophase.Ascomparedtotestingundersinusoidalflux(sinusoidalB)conditions,thepermeabilitiesdeterminedbythismethodarenumericallylowersince,foragiventestsignalfrequency,therateoffluxchange(dB/dt)ishigher.Thistestmethodissuitableforimpedancepermeabilitymeasurementsatverylowmagneticinductionsatpowerfrequencies(50to60Hz)tomoderateinductionsbelowthepointofmaximumpermeabilityofthematerial(thekneeofthemagnetizationcurve)oruntilthereisvisibledistortionofthecurrentwaveform.Thelowerlimitisafunctionofsamplearea,secondaryturns,andthesensitivityoftheflux-readingvoltmeterused.Athigherinductions,measurementsofflux-generatedvoltagesthatareappreciablydistortedmeanthatthefluxhasappreciableharmonicfrequencycomponents.Theupperlimitisgivenbytheavailabilityofpuresinusoidalcurrent,whichisafunctionofthepowersource.Inaddition,alargeratio(x2265;10)ofthetotalseriesresistanceoftheprimarycircuittotheprimarycoilimpedanceisrequired.Withpropertestapparatus,thistestmethodissuitableforuseatfrequenciesupto1MHz.Thistestmethodissuitablefordesign,specificationacceptance,serviceevaluation,qualitycontrol,andresearchuse.1.1Thistestmethodprovidesameansfordeterminationoftheimpedancepermeability(181z)offerromagneticmaterialsundertheconditionofsinusoidalcurrent(sinusoidalH)excitation.Testspecimensintheformoflaminatedtoroidalcores,tape-woundtoroidalcores,andlink-typelaminatedcoreshavinguniformcrosssectionsandclosedfluxpaths(noairgaps)areused.Themethodisintendedasameansfordeterminingthemagneticperformanceofferromagneticstriphavingathicknesslessthanorequalto0.025in.[0.635mm].1.2ThistestmethodshallbeusedinconjunctionwiththoseapplicableparagraphsinPracticeA34/A34M.1.3Thevaluesandequationsstatedincustomary(cgs-emuandinch-pound)orSIunitsaretoberegardedseparatelyasstandard.Withinthisstandard,SIunitsareshowninbracketsexceptforthesectionsconcerningcalculationswherethereareseparatesectionsfortherespectiveunitsystems.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnonconformancewiththisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:H21
【国际标准分类号】:29_030
【页数】:4P.;A4
【正文语种】:英语