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:×××同学问:《傻二哥》中的“傻二哥”是一个什么样的人?你能不能给我们作一点简要的分析?答:作品开头部分介绍了“傻二哥”得名的缘由:“他还有一个特点:爱帮人忙,一帮就帮到底,有股子热心的傻劲儿。从来没听说他有学名,冲他这股傻劲,人家忘了他的聪明,给他起了个雅号,叫傻二哥!说他‘傻灵傻灵’的。”傻二哥的最主要的特征就是“傻灵傻灵”。先解释一下“傻灵”在文章中的含义。“傻”字本来带有贬义,指“愚蠢,糊涂”或“死心眼,不知变通”。但是,在这篇课文中,贬词褒用,意思是“为人老实,不自私,不取巧”。而“灵”字,在这篇课文的意思是“聪明”。“傻灵”二字,是赞扬傻二哥又老实又聪明,是对傻二哥性格特征的准确概括。