简介:摘要:随着经济的快速发展,人们对石油类产品的需求急剧增加,大量的石油碳氢化合物在石油产品的开采、运输、加工和储存及使用过程中泄露至环境中,全球每年约有800万t石油污染物进入生态环境,我国每年也约有60万t石油污染物进入环境,对生态环境造成持久且难以修复的破坏,严重威胁着人类的健康。与此同时,石油烃中含有的长链烷烃和多环芳香烃等因其结构稳定难以被降解,给修复带来了严峻的挑战。石油烃污染的修复技术可分为物理修复、化学修复和生物修复三大类。其中,物理修复方法是指通过物理手段将石油烃污染物质移除或转化为低毒或者无毒形态的技术手段,主要包括有土壤置换、气相抽取、萃取洗脱、电动修复、热脱附等技术。基于此,本篇文章对土壤中石油烃(C10~C40)的前处理方法进行研究,以供参考。
简介:TheJOURNALOFANCIENTCIVILIZATIONS(JAC)ispublishedannuallybytheInstitutefortheHistoryofAncientCivilizations(northeastnormaluniversity,Changchun,JilinProvince,People’sRepublicofChina).Thisyear,weareproudtopresentthe30thvolumetotheacademicaudience.Firstissuedin1986afterthefoundationof
简介:AmethodconstructinqC~1Piecewisequinticpolynomialoveratriangulargridtointerpo-latefunctionvaluesandpartialderivativesatverticesispresentedinthispaper.Thesetofprecisepoly-nomialsofthismethodisdiscussed.
简介:Afamilyofpiecewiserationalquinticinterpolationispresented.Eachinterpolationofthefamily,whichisidentifieduniquelybythevalueofaparameterαi,isofC2continuitywithoutsolvingasystemofconsistencyequationsforthederivativevaluesattheknots,andcanbeexpressedbythebasisfunctions.InterpolantisofO(hr)accuracywhenf(x)?Cr[a,b],andtheerrorshaveonlyasmallfloatingforabigchangeoftheparameterαi,itmeanstheinterpolationisstablefortheparameter.Theinterpolationcanpreservetheshapepropertiesofthegivendata,suchasmonotonicityandconvexity,andaproperchoiceofparameterαiisgiven.
简介:Inthispaper,weintroduceaconditionweakerthantheLpdifferentiability,whichwecallCpcondition.Weprovethatifafunctionsatisfiesthisconditionatapoint,thenthereexiststhebestlocalapproximationatthatpoint.WealsogiveanecessaryandsufficientconditionforthatafunctionbeLpdifferentiable.Inaddition,westudytheconvexityofthesetofclusterpointsofthenetofbestappoximationsoff,{Pe(f)}ase→0.