简介:Verticalprofilesfortheuranium-seriesradioisotopes210Pband210Powereobtainedatthetwohydrothermalventsites,theIheyaRidgeandtheMinami-EnseiKnoll,intheMid-OkinawaTroughin1993and1994,respectively.In1995,bothradioisotopesweremeasuredattheMinami-EnseiKnollagain.AttheIheyaRidge,wherethehydrothermalactivityisnotactiveasreflectedbytheCH4and222Rndata,boththetotal210Pband210Poactivitiesshowdeficiencyrelativetotheirparents,andthemeanresidencetimeof210Pband210Poisapproximatelyequalto20and2~5a,respectively.AttheMinami-EnseiKnoll,whichischaracterizedbyblacksmokers,thetotal210Pb(0.167×10-3~2.5×10-3Bq/kg)aroundtheplumesisdeficientrelativeto226Rabutthetotal210Poactivities(1.83×10-3~2.83×10-3Bq/kg)areinexcessrelativeto210Pb.The210PoactivitiesarehigherthanthoseintheEastChinaSeaandtheOkinawaTroughandexcess210Pohasbeenfound.The210Pb/226Raand210Po/210Pbactivityratiosare0.1~0.4and1.1~7.8,respectively.210Pbispreferentiallyscavengedinthehydrothermalplumes.Thepossiblemechanismsgoverningtheconcentrationof210PbintheMinami-EnseiKnollinvolvealateraltransportof210Pbviadiffusion.Thehigh210Po/210Pbactivityratiosinthehydrothermalplumessuggestadepletionof210Pbandadditionof210Pointhehydrothermalventarea.
简介:西此大学陆文盛同学:最近几年来,PX项目在国内引起很大争议,但又有报道说,国外都在大力发展PX项目。请问——答:在谈PX项目之前,我们先要搞清楚什么是PX。PX是英文para-xylene的缩写,中文叫作对二甲苯。在常态下,PX是无色透明的液体,比水轻,但不溶于水。在日常生活中,人们是不会直接接触到PX的,能见到的都是用PX作为原料生产的产品。不夸张地说,现代人的生活中,到处都离不开PX。PX是生产聚酯材料的重要的基础原料,我们平时穿的衣服、盖的被子、家里挂的窗帘,很多都是用聚酯纤维做的。我们常喝的矿泉水、饮料等各种瓶子,去医院看病拍片用的胶片,也都是聚酯材料做的。此外,PX也是提高汽油高性能抗爆性的重要组分,汽油中添加适量的PX,可使其动力性更佳。
简介:摘要:PX(对二甲苯)是重要的芳烃产品,主要用来制备对苯二甲酸(PTA)以及对苯二甲酸二甲酯(DMT),进而生产聚对苯二甲酸乙二醇酯(PET),在整个化纤产业链中处于源头地位。主要用于生产聚酯纤维、塑料、涂料和胶粘剂等。由于其广泛的用途和市场需求,PX的生产和供应链在全球范围内都非常重要。目前国内生产PX供给端主要集中在三桶油、荣盛、恒力、恒逸等民营企业,本文重点对PX装置核心设备旋转阀进行介绍。
简介:IntheprocessofinvestigationondomesticPTAprojecttheResearchInstituteofSINOPECYangziPetrochemicalCompanyundertakestoperform“AnalysisandprocessoptimizationofAmocohigh-temperatureoxidationtechnology”,“DevelopmentandcommercializationstudyonnovelcatalystforsynthesisofPTA”,“StudyonPTAoxidationreaction”,and