简介:SeismicPvelocitystructureisdeterminedfortheupper500kmoftheinnercoreandlowermost200kmoftheoutercorefromdifferentialtraveltimesandamplituderatios.ResultsconfirmtheexistenceofagloballyuniformFregionofreducedPvelocitygradientinthelowermostoutercore,consistentwithironenrichmentneartheboundaryofasolidifyinginnercore.Pvelocityoftheinnercorebetweenthelongitudes45oEand180oE(quasi-EasternHemisphere)isgreaterthanorequaltothatofanAK135-Freferencemodelwhereasthatbetween180oWand45oE(quasi-WesternHemisphere)islessthanthatofthereferencemodel.Observationofthisheterogeneitytoadepthof550kmbelowtheinnercoreandtheexistenceoftransitionsratherthansharpboundariesbetweenquasi-hemispheresfavoreithernoorveryslowinnercoresuperrotationoroscillationswithrespecttothemantle.DegreeoneseismicheterogeneitymaybebestexplainedbyactiveinnercorefreezingbeneaththeequatorialIndianOceandominatingstructureinthequasi-EasternHemisphereandinnercoremeltingbeneathequatorialPacificdominatingstructureinthequasi-WesternHemisphere.Variationsinwaveformsalsosuggesttheexistenceofsmaller-scale(1to100km)heterogeneity.
简介:Inthelastseveralyearssince2004animportantnewfindinghasbeenunveiledbycombinedeffortsduetoJapanese(SatoruTanaka),French(RenaudDeguen,TAlbousierreandMarcMonnereau),AmericanandChinesegeophysicists(XiaodongSongandVernonFCormier)whoemployedfromunambiguousdetailedseismologicalevidenceandexplainedbycleartheoreticalandsoundlaboratoryargumentsdrawnfromfluiddynamicsthatthereexistsastrong
简介:AttheinitialoperationstageofthecontinuousbloomcasteratBaosteel,alotofcentralporosityandcracksoccurredinblooms,especiallyinthebloomsofhigh-pressureboilersteel.Inthisstudy,amodelofheattransferandsolidificationwassetuptoanalyzetheprocessofcontinuousbloomcasting.Basedonthemodel,thedistributionsoftemperaturefieldandshellthicknesswereobtained,themushyzonewasdefined,andtherebythetechnologyofsoftreductionforbloomswasdeveloped.Afterseveraltestswereconducted,areasonabletestplanwasdeveloped,whichledtothedeterminationoftheoptimalreductionzoneandgaugereduction.Now,centralporosityandcracksinbloomsarealmostavoidedandtheinnerqualityhasbeenobviouslyimproved.
简介:我们进行一个实验调查在在PKP光线路径在中美洲下面取样的内部核心的体积的观察速度坡度的线性是否是柔韧的近似。而不是解决一个优化问题,我们在贝叶斯的推理以内走近它。在模型说明被放松以便的地方,这是一条整体途径而不是仅仅一个答案,一些讲理的模型是可接受的。在贝叶斯的推理这里使用了的transdimensional,而且,基础功能的数字需要为观察建模由自己一未知。我们建模在模型的整体揭示那,很可能是包含仅仅2个节点(线性趋势)的那些。因此,我们的结果认为关于观察坡度在它的性质是不变的披风的其余部分为内部核心旋转的决心使用的假设正当(线性)。在地震学的最近的观察建议在有弹性的参数的空间可变性是在内部核心的普遍现象,是可能的。未来数组观察将进一步抑制速度变化的空间程度和大小并且显示出是否在内部核心的二伪半球的这些观察之间有重要差别。
简介:在东方半球的PKP(DF)的变细以同时解释一种思索的关系的多重散布被检验,相应于强壮的变细的一个相对快的速度异例。有一个维的随机的速度变化的反射率synthetics与振幅比率和微分旅行为赤道的路径PKP(Cdiff)-PKP(DF)预定的PKP(DF)/PKP(Cdiff)的观察相比。有5%,6%,和7%的标准差在的P波浪速度变化的Gaussian分布最高内部核心的200km在是比在东方半球的典型结构稍微快的速度结构上被附加,根据仅仅一个维的结构被考虑,它是可能的解释旅行时间和振幅数据。在二的scatterer分发特征、三尺寸的统计数值的进一步的考试被要求获得一个现实主义的结论。