简介:摘要对PVC-U、PVC-C、PP-R等多种常见塑料管材的特点分类介绍优缺点,并对检验过程中出现的问题进行分析,指导用户及生产厂家进行选择和生产。
简介:TheresumptionofdiplomaticrelationsbetweentheUnitedStatesandCubaisnotonlyakeyresultofObama’s"reaching-out"diplomacybutisalsocloselyconnectedtoUSelectionpolitics.TheUSembargoonCubawillhopefullybeliftedsoonunlesssomepoliticalhurdleemerges.Evenso,normalizationofUS-Cubanrelationsstillhasalongwaytogo.
简介:TomoreindepthunderstandthedopingeffectsofoxygenonSiGealloys,boththemicro-structureandpropertiesofO-dopedSiGe(including:bulk,(001)surface,and(110)surface)arecalculatedbyDFT+Umethodinthepresentwork.Thecalculatedresultsareasfollows.(i)The(110)surfaceisthemainexposingsurfaceofSiGe,inwhichOimpuritypreferstooccupythesurfacevacancysites.(ii)ForOinterstitialdopingonSiGe(110)surface,theexistencesofenergystatescausedbyOdopinginthebandgapnotonlyenhancetheinfraredlightabsorption,butalsoimprovethebehaviorsofphoto-generatedcarriers.(iii)ThefindingaboutdecreasedsurfaceworkfunctionofO-dopedSiGe(110)surfacecanconfirmpreviousexperimentalobservations.(iv)Inallcases,Odoingmainlyinducestheelectronicstructuresnearthebandgaptovary,butisnotdirectlyinvolvedinthesevariations.Therefore,thesefindingsinthepresentworknotonlycanprovidefurtherexplanationandanalysisforthecorrespondingunderlyingmechanismforsomeoftheexperimentalfindingsreportedintheliterature,butalsoconducetothedevelopmentofμc-SiGe-basedsolarcellsinthefuture.