简介:摘要:随着工业化发展, SA335-P91钢 在电厂受到的欢迎。 通过对SA335-P91钢的成分 及 性能分析确定其影响性能的因素 ,采取对热处理过程的控制及管理手段保障最终的焊接接头性能,为提供可靠的产品提供保障 。
简介:Thevolcano-sedimentarysuccessionaroundWadiZaghrainSinai,atthenorthernmostsegmentoftheArabianNubianShield,comprisesvolcanicrocksinterbeddedwithratherimmaturesediments.Thesuccessionisdominatedbyintermediatetosilicicvolcanicsofmedium-tohigh-Kcalc-alkalineaffinity.Itisdividedintotwounits,thelowerunitincludesintermediaterocksanddacitesinterbeddedwithgraywackes,semi-pelitesandpelitesandtoppedbypolymictconglomerates.Thisunitissubjectedtofoldingandregionalmetamorphism(uptogarnetzone)andisintrudedbyquartzdiorite-granodioriteinducing,locally,low-pressurecontactthermalmetamorphism.Theunmetamorphosedupperunitencompassesacidvolcanicsintercalatedwithlitharenite,sublithareniteandminorarenite.Therhyolitesofthisunitpertaintothehighlyfractionatedgranitesandarecharacterizedbyanagpaiticindex(NK/A)rangingfrom0.87to0.96.Theymayreflecteitherextensiveinteractionofsubduction-relatedmagmaswiththecontinentalcrustorachangeinthetectonicregime.Thepresentlithologicalandgeochemicalcharacteristicsofthestudiedsedimentstogetherwithavailablezirconagesindicateratherdistalprovenanceoftheirdetritus.Thisdetrituscomprisesfluvial-alluvialsedimentsaccumulatedintheintermontanebasins,whicharehalf-grabensortiltedfaultblocks.Thetectonicsettingofthedepositionalbasinsisactivecontinentalmarginandcontinentalislandarcs.GeochemicalpatternsoftheZaghravolcano-sedimentarysuccessionindicatetheircorrelationwiththeDokhanVolcanics-HammamatClasticssequenceoftheEasternDesertofEgypt.Also,theZaghravolcanicsdisplaygeochemicalsimilaritieswiththoseexposedinSinai,attheRutig,FeraniandIqnaShar’aareas.TheZaghrasuccessionisdatedasEdiacaranbutisnotrelatedeithertotheensimaticislandarcassemblageortotherift-relatedassemblageformedduringtheearlystagesofthebreak-upofRodiniaaspreviouslythought.
简介:目的探讨右室基底段心室拖带时刺激心房(SA)间期与原心动过速时心室心房(VA)间期的差值,即SA-VA间期对房室折返性心动过速(atrioventricularreentranttachycardia,AVRT)与房室结折返性心动过速(atrioventricularnodalreentranttachycardia,AVNRT)的鉴别价值。方法选取67例体表心电图无明显预激波的窄QRS心动过速患者,在右室基底段拖带心动过速。测量SA-VA间期、拖带后校正回归间期(即校正的起搏后间期与心动过速周长的差值)等电生理参数,并比较其鉴别阵发性室上性心动过速机制的有效性。结果旁道介导AVRT共19例,其中游离壁旁道13例,间隔旁道6例;AVNRT共48例,其中典型35例,不典型13例。校正回归间期>95ms诊断AVNRT和AVRT的敏感性、特异性、阳性预测值和阴性预测值分别为90%、90%、96%和78%;而SA-VA间期>80ms诊断二者的敏感性、特异性、阳性预测值和阴性预测值分别为94%、84%、94%和85%。其中SA-VA间期≤50ms鉴别间隔旁道介导AVRT和不典型AVNRT的敏感性、特异性均能达到100%。结论在右室基底段心室拖带下,SA-VA间期能够简便、有效地鉴别AVRT与AVNRT。
简介:摘要本文主要就T91与1Cr18Ni9Ti采用镍基焊接材料进行焊接工艺和焊接操作方面研究,从而确定镍基焊接材料焊接的可行性。