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【英文标准名称】:StandardPracticeforMagneticParticleExaminationofSteelForgingsUsingAlternatingCurrent
【原文标准名称】:用交流电检验钢锻件磁粉粒的标准实施规程
【标准号】:ASTMA966/A966M-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(ASTM)
【起草单位】:ASTM
【标准类型】:()
【标准水平】:()
【中文主题词】:交流电流;电流;检验;锻件;磁粉粒;钢;试验方法;测试
【英文主题词】:Alternatingcurrent;Currents;Examinations;Forgings;Magneticparticles;Steels;Testmethods;Testing
【摘要】:
【中国标准分类号】:H26
【国际标准分类号】:77_040_20;77_140_85
【页数】:6P;A4
【正文语种】:英语


【英文标准名称】:StandardTestMethodforDeterminingtheMolarMassofChitosanandChitosanSaltsbySizeExclusionChromatographywithMulti-angleLightScatteringDetection(SEC-MALS)
【原文标准名称】:用多角度光散射器尺寸筛析色谱法(SEC-MALS)测定壳聚糖和壳聚糖盐摩尔质量的标准试验方法
【标准号】:ASTMF2602-2008e1
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【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】:F04.42
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:Chitosansalts;Sizeexclusionchromatographywithmulti-anglelightscatteringdetection(SEC-MALS);Tissueengineeredmedicalproducts(TEMPs)
【摘要】:Thedegreeofdeacetylationofchitosan,aswellatthemolarmassandmolarmassdistribution,determinesthefunctionalityofchitosaninanapplication.Forinstance,functionalandbiologicaleffectsarehighlydependentuponthecompositionandmolarmassofthepolymer.Thistestmethoddescribesproceduresformeasurementofmolarmassofchitosanchloridesandglutamates,andchitosanbase,althoughitinprincipleappliestoanychitosansalt.Themeasuredmolarmassisthatforchitosanacetate,sincethemobilephasecontainsacetateascounterion.Thisvaluecanfurtherbeconvertedintothecorrespondingmolarmassforthechitosanasabase,ortheparentsaltform(chlorideorglutamate).Lightscatteringisoneofveryfewmethodsavailableforthedeterminationofabsolutemolarmassandstructure,anditisapplicableoverthebroadestrangeofmolarmassesofanymethod.Combininglightscatteringdetectionwithsizeexclusionchromatography(SEC),whichsortsmoleculesaccordingtosize,givestheabilitytoanalyzepolydispersesamples,aswellasobtaininginformationonbranchingandmolecularconformation.Thismeansthatboththenumber-averageandmass-averagevaluesformolarmassandsizemaybeobtainedformostsamples.Furthermore,onehastheabilitytocalculatethedistributionsofthemolarmassesandsizes.Multi-anglelaserlightscattering(MALS)isatechniquewheremeasurementsofscatteredlightaremadesimultaneouslyoverarangeofdifferentangles.MALSdetectioncanbeusedtoobtaininformationonmolecularsize,sincethisparameterisdeterminedbytheangularvariationofthescatteredlight.Molarmassmayinprinciplebedeterminedbydetectingscatteredlightatasinglelowangle(LALLS).However,advantageswithMALSascomparedtoLALLSare:(1)lessnoiseatlargerangles,(2)theprecisionofmeasurementsaregreatlyimprovedbydetectingatseveralangles,and(3)theabilitytodetectangularvariationallowsdeterminationofsize,branching,aggregation,andmolecularconformation.Sizeexclusionchromatographyusescolumns,whicharetypicallypackedwithpolymerparticlescontaininganetworkofuniformporesintowhichsoluteandsolventmoleculescandiffuse.Whileinthepores,moleculesareeffectivelytrappedandremovedfromtheflowofthemobilephase.Theaverageresidencetimeintheporesdependsuponthesizeofthesolutemolecules.Moleculesthatarelargerthantheaverageporesizeofthepackingareexcludedandexperiencevirtuallynoretention;theseareelutedfirst,inthevoidvolumeofthecolumn.Molecules,whichmaypenetratetheporeswillhavealargervolumeavailablefordiffusion,theywillsufferretentiondependingontheirmolecularsize,withthesmallermoleculeselutinglast.Forpolyelectrolytes,dialysisagainsttheelutionbufferhasbeensuggested,inordertoeliminateDonnan-typeartifactsinthemolarmassdeterminationbylightscattering(1,2).However,inthepresentmethod,thesizeexclusionchromatographystepprecedingthelightscatterdetectionisanefficientsubstituteforadialysisstep.ThesampleisseparatedonSECcolumnswithlargeexcessofelutionbufferfor30to40min,anditisthereforeinfullequilibriumwiththeelutionbufferwhenitreachestheMALSdetector.1.1Thistestmethodcoversthedeterminationofthemolarmassofchitosanandchitosansaltsintendedforuseinbiomedicalandpharmaceuticalapplicationsaswellasintissueengineeredmedicalproducts(TEMPs)bysizeexclusionchromatographywithmulti-anglelaserlightscatteringdetection(SEC-MALS).AguideforthecharacterizationofchitosansaltshasbeenpublishedasGuideF2103.1.2Chitosanandchitosansal......
【中国标准分类号】:C10
【国际标准分类号】:11_120_10
【页数】:7P.;A4
【正文语种】:英语