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:介绍了南开大学在实用Tl和Hg系高温超导薄膜方面的研究工作。在Tl系高温超导研究领域,利用磁控溅射和后退火两步法在LaAlO3(001)衬底上制备出高质量的Tl-1212和Tl-2212超导薄膜,超导临界转变温度Tc分别为92K和106K;在两步法的基础上,利用两次后退火,得到Tl,Bi-1223超导薄膜,超导临界转变温度Tc可以达到110K;同时,利用阳离子置换反应技术,在Tl-1212和Tl-2212超导薄膜基础上得到Hg-1212超导薄膜,利用Tl-2223超导薄膜作为先驱膜,得到Hg-1223超导薄膜,结果显示,Hg-1212和Hg-1223超导薄膜的临界转变温度Tc可分别高达124K和132K。为满足Tl系高温超导薄膜的微波应用需求,分别在LaAlO3、蓝宝石、氧化镁(MgO)衬底上制备出2英寸双面Tl-2212超导薄膜,该超导薄膜具有均匀的超导特性,薄膜超导特性优良,为制备高温超导微波无源器件提供了基础。
简介:Consideringtheperturbation,theresultsoftheoreticalcalculationoffiveRydbergseriesenergylevels6s~2ns~2S_(1/2)(n=7-20),6s~2nd~2D_(3/2)(n=6-20),6~s2nd~2D_(5/2)(n=6-20),6s~2np~2p_(1/2)~0(n=7-20),and6s~2np~2p_(3/2)~0(n=7-20)forT11arepresentedusingtheweakestboundelectronpotentialmodel(WBEPM)theory.Furthermore,theradiativelifetimesofthisfiveseriesarealsocalculated.Thecalculatedvaluesofenergylevelsandlifetimesareingoodagreementwiththeexperimentalresults.
简介:摘要目的通过分娩镇痛产妇的观察与分析,最大限度地减轻分娩疼痛,提高自然分娩率,总结经验与教训。方法对210例分娩镇痛患者第一产程时间,活跃期时间及第二产程时间与未使用分娩镇痛自然分娩产妇进行对比。结果分娩镇痛产妇,第一产程时间,活跃期时间明显缩短,会阴侧切率降低,而第二产程时间无明显差异。
简介:中图分类号R714.2文献标识码B文章编号1672-3783(2015)07-0142-01摘要目的探讨子痫前期影响妊娠结局的相关因素分析。方法选择子痫前期患者210例,分为重度子痫前期组108例,轻度子痫前期组102例,对两组患者的肝肾功能损害、低蛋白血症、新生儿窒息、死产、胎儿窘迫发生率、早产发生率及产后出血发生率进行统计分析。结果轻度组肝肾功能损害、低蛋白血症、新生儿窒息、死产、产后出血及胎儿窘迫发生率均小于重度组(P<0.05、P<0.01),早产发生率两组之间差异无显著性(P>0.05)。结论及时有效控制血压,适时终止妊娠,有益于改善妊娠结局。