基本信息
| 标准名称： | 饲料用蚕豆 |
| 中标分类： |
农业、林业 >>
畜牧 >>
畜禽饲料与添加剂 |
| 替代情况： | 调整为NY/T 138-1989 |
| 发布日期： | 1900-01-01 |
| 实施日期： | 1900-01-01 |
| 首发日期： | 1900-01-01 |
| 作废日期： | 1900-01-01 |
| 出版日期： | 1900-01-01 |
| 页数： | 2页 |
适用范围
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前言
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引用标准
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所属分类： 农业 林业 畜牧 畜禽饲料与添加剂
【英文标准名称】:Ambientair-Determinationofasbestosfibres-Indirect-transfertransmissionelectronmicroscopymethod
【原文标准名称】:环境空气石棉纤维的测定间接传递电子显微镜法
【标准号】:ISO13794-1999
【标准状态】:现行
【国别】:国际
【发布日期】:1999-07
【实施或试行日期】:
【发布单位】:国际标准化组织(ISO)
【起草单位】:ISO/TC146
【标准类型】:()
【标准水平】:()
【中文主题词】:石棉粉;定义;定义;含量测定;石棉;环境空气;显微分析;空气污染;空气质量
【英文主题词】:Airpollution;Airquality;Ambientair;Asbestos;Asbestosdust;Definition;Definitions;Determinationofcontent;Microscopicanalysis
【摘要】:1SubstancedeterminedThisInternationalStandardspecifiesareferencemethodusingtransmissionelectronmicroscopy(TEM)fordeterminationoftheconcentrationofasbestosstructuresinambientatmospheres.Thespecimenpreparationprocedureincorporatesashinganddispersionofthecollectedpaniculate,sothatallasbestosismeasured,includingtheasbestosoriginallyincorporatedinparticleaggregatesorparticlesofcompositematerials.Thelengths,widthsandaspectratiosoftheasbestosfibresandbundlesaremeasured,andthese,togetherwiththedensityofthetypeofasbestos,alsoallowthetotalmassconcentrationofairborneasbestostobecalculated.Themethodallowsdeterminationofthetype(s)ofasbestosfibrepresent.Themethodcannotdiscriminatebetweenindividualfibresoftheasbestosandnon-asbestosanaloguesofthesameamphibolemineral.2TypeofsampleThemethodisdefinedforpolycarbonatecapillary-porefiltersorcelluloseester(eithermixedestersofcelluloseorcellulosenitrate)filtersthroughwhichaknownvolumeofairhasbeendrawn.Themethodissuitablefordeterminationofasbestosinbothexteriorandbuildingatmospheres.3RangeTheupperlimitfortherangeofconcentrationthatcanbemeasuredontheanalyticalfilteris7000structures/mm.Thelowerlimitoftherangethatcanbemeasuredontheanalyticalfiltercorrespondstodetectionof2,99structuresintheareaofspecimenexamined.Theairconcentrationsrepresentedbythesevaluesareafunctionofthevolumeofairsampledandthedegreeofdilutionorconcentrationselectedduringthespecimenpreparationprocedures.Themethodisparticularlyapplicableformeasurementsinareaswithhighsuspended-particulateconcentrations(exceeding10μg/m),orwheredetectionandidentificationofasbestosfibresarelikelytobepreventedorhinderedbyothertypesofparticulateindirect-transferTEMpreparations.Intheory,thereisnolowerlimittothedimensionsofasbestosfibreswhichcanbedetected.Inpractice,microscopistsvaryintheirabilitytodetectverysmallasbestosfibres.Therefore,aminimumlengthof0,5μmhasbeendefinedastheshortestfibretobeincorporatedinthereportedresults.4LimitofdetectionThelimitofdetectiontheoreticallycanbeloweredindefinitelybyfiltrationofprogressivelylargervolumesofair,concentratingthesampleduringspecimenpreparation,andbyextendingtheexaminationofthespecimensintheelectronmicroscope.Inpractice,thelowestachievablelimitofdetectionforaparticularareaofTEMspecimenexaminediscontrolledbythetotalsuspendedparticulateconcentrationremainingaftertheashingandaqueousdispersalsteps,andthisdependsonthechemicalnatureofthesuspendedparticulate.Fortotalsuspendedparticulateconcentrationsofapproximately10μg/m,correspondingtoclean,ruralatmospheres,andassumingfiltrationof4000litresofair,ananalyticalsensitivityof0,5structure/litrecanbeobtained,equivalenttoalimitofdetectionof1,8structures/litre,ifanareaof0,195mmoftheTEMspecimensisexamined.LowerlimitsofdetectioncanbeachievedbyincreasingtheareaoftheTEMspecimenthatisexamined,orbyconcentrationofthesampleduringspecimenpreparation.Inordertoachievelowerlimitsofdetectionforfibresandbundleslongerthan5μm,andforPCM-equivalentfibres,lowermagnificationsarespecifiedwhichpermitmorerapidexaminationoflargerareasoftheTEMspecimenswhentheexaminationislimitedtothesedimensionsoffibre.
【中国标准分类号】:Z15
【国际标准分类号】:13_040_20
【页数】:64P;A4
【正文语种】:英语