【英文标准名称】:Sealedradioaktivesources;leakagetestmethodsforrecurrentinspections
【原文标准名称】:密封放射性材料.使用时的密封性检验
【标准号】:DIN25426T.4-1977
【标准状态】:作废
【国别】:
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【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】:
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【英文标准名称】:StandardTestMethodforPrecipitatedSilica-SurfaceAreabyMultipointBETNitrogenAdsorption
【原文标准名称】:用多点布-埃-特氮气吸附法对沉积二氧化硅表面面积的测试方法
【标准号】:ASTMD1993-2003(2008)
【标准状态】:现行
【国别】:美国
【发布日期】:2003
【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】:D11.20
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:nitrogenadsorptionsurfacearea;precipitatedhydratedsilica;silicas;surfacearea;BET(Brunauer,Emmett,andTeller)surfacearea;Gasadsorption;Hydratedsilica;Nitrogenadsorptionsurfacearea;Precipitatedhydratedsilica;Silica;Surfaceanalys
【摘要】:Thistestmethodisusedtomeasurethesurfaceareaofprecipitated,hydratedsilicasthatisavailabletothenitrogenmoleculeusingthemultipoint(B.E.T.)method.Solidsadsorbnitrogenand,underspecificconditions,theadsorbedmoleculesapproachamonomolecularlayer.ThequantityinthishypotheticalmonomolecularlayeriscalculatedusingtheBETequation.Combiningthiswiththeareaoccupiedbythenitrogenmoleculeyieldsthetotalsurfaceareaofthesolid.Thistestmethodmeasurestheestimatedquantityofnitrogeninthemonomolecularlayerbyadsorptionatliquidnitrogentemperatureandatseveral(atleastfive)partialpressuresofnitrogen.Beforeasurfaceareadeterminationcanbemadeitisnecessarythatthesilicabestrippedofanymaterialwhichmayalreadybeadsorbedonthesurface.Thestrippingofadsorbedforeignmaterialeliminatestwopotentialerrors.Thefirsterrorisassociatedwiththeweightoftheforeignmaterial.Theseconderrorisassociatedwiththesurfaceareathattheforeignmaterialoccupies.1.1ThistestmethodcoversaprocedurewhichisusedtomeasurethesurfaceareaofprecipitatedhydratedsilicasbytheconventionalBrunauer,Emmett,andTeller(BET)theoryofmultilayergasadsorptionbehaviorusingmultipointdeterminations,similartothatusedforcarbonblackinTestMethodsD4820.Thistestmethodspecifiesthesamplepreparationandtreatment,instrumentcalibrations,requiredaccuracyandprecisionofexperimentaldata,andcalculationsofthesurfacearearesultsfromtheobtaineddata.1.2Thistestmethodisusedtodeterminethenitrogensurfaceareaofprecipitatedsilicaswithspecificsurfaceareasintherangeof1to50hm2/kg(10to500m2/g).1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Theminimumsafetyequipmentshouldincludeprotectivegloves,sturdyeyeandfaceprotection,andmeanstodealsafelywithaccidentalmercuryspills.
【中国标准分类号】:G13
【国际标准分类号】:71_060_20
【页数】:3P.;A4
【正文语种】:英语