简介:Thisworkaimedtoresearchthestructuremodelsofamorphousmaterials.Fiveamorphousandparacrystallinesamples(naturalorartificial)wereinvestigatedvia29Si/27Alnuclearmagneticresonance(NMR)andfieldemissionscanningelectronmicroscopy/energydispersivespectroscopy(FE-SEM/EDS).TheresultsofNMRshowedtheresonancesofdifferentspecimens:-93.2ppm,-101.8ppm,-111.8ppmfornaturalpozzolanaopalshale(POS).ThesepeakswereassignedtotheQ2(2OH),Q3(OH)/Q4(1Al)andQ4respectively.Theresultsof27AlMASNMRindicatedthatAlsubstitutedforSisiteintetrahedralexistinginthePOS,whiletheAl/Siatomicratioinopalwaslow(around0.04).Forthealkali-silicate-hydrategel,therewereatleastthreeresolvedsignalsassignedtoQ0andQ1,respectively.Forthefusedsilicaglasspowder,thereweretheprimarysignalscenteredaboutattherangefrom-107to-137ppm,whichwereassignedtoQ4units.Inaddition,thepeaksataround-98and-108ppmwerecorrespondingtoQ3(1OH)andQ4unitsexistinginaerogelsilicastructure.
简介:为帮助工厂了解活性组分在催化剂载体表面的分布情况,利用扫描电子显微镜和X-射线能量色散谱(SEM—EDS)进行测试分析,结果显示,500—6/5000—12测试法能简单有效地对催化剂上元素的分布情况进行表征,对催化剂表面上活性组分的分布研究具有重要研究价值。
简介:Thecoarseporesystem,interfacialtransitionzone(ITZ)betweenaggregateandpastematrixandvolumefractionofunhydratedcementinconcrete(w/c=0.3)containingmineraladmixtureswerequantitativelycharacterizedbythescanningelectronmicroscope-backscatteredelectron(SEM-BSE)imageanalysistechnique.Theexperimentalresultsshowthatcompoundadditionofslagandflyashdecreasesthecoarseporosityfrom10.17%to3.74%andthethresholddiameterofcoarseporesizefrom345μmto105μmcomparedwithconcrete(w/c=0.30)withoutmineraladmixtures;Moreoverwithcompoundadditionofflyashandslag,thevolumeproportionofunhydratedcementinpastematrixisreducedby30%,themaximumamountofcoarseporesintheITZbetweenaggregateandpastedecreasesfrom13.11%to5.57%andthethicknessofITZisreducedby37%,comparedwithconcretewithoutmineraladmixtures.