简介：以^13C（α,n)^16O和^22Ne(α，n）^25Mg作为双脉冲中子源，对于星族Ⅰ低质量AGB星，采用无分叉s-过程反应通道，结合最新恒星深化的计算结果，在各物理参量合理取值范围内，计算了He壳层内重元素核合成。结果表明，渐近分布时所需的脉冲数N0的范围是6－16个，渐近分布达到后，He壳层内重元素的丰度仅与平均中子辐照量τ0有关。与低质量AGB星相应的平均中子辐照量范围是τ0=0.15-1.0mb^-1。

简介：该文简要介绍了地震堰塞湖、火山堰塞湖、冰碛堰塞湖的形成原因及特点。

简介：Therearemanyfactorsaffectingthechemicalcharacteristicsofgroundwaterintheformingprocessofgroundwaterchemicalfields,suchasfresheningduetometeoricwaterleachingdownwards,fresheningduetomudstonecompactionandwaterrelease,concentrationduetoinfiltrationandfresheningduetodehydrationofclayminerals.Asaresult,thegroundwaterchemicalfieldsarecharacterizedbylengthwisestagesandplanarselectivity.Theformerarousesverticalchemicalzonalityofgroundwater.FiveunitscouldbeidentifieddownwardsintheSongliaobasin:(1)fresheningzoneduetodownward-leachingmeteoricwater,(2)concentrationzoneduetoevaporationnearthegroundsurface,(3)fresheningzoneduetomudstonecompactionandwaterrelease,andconcentrationzoneduetocompactionandinfiltration,(4)fresheningzoneduetodehydrationofclayminerals,and(5)filtration-concentrationzone;whereasthelatterdeterminestheplanardivisionofgroundwaterchemicalfields:(1)thefresheningareaduetometeoricwater,asymmetricallyonthemarginofthebasin,(2)thefresheningareaduetomudstonecompactionandwaterreleaseinthecentralpartofthebasin,(3)theleakyarea,whichisatransitionalzone,and(4)leakage-evaporationarea,whichisaconcentrationzone.Inthedirectionofcentrifugalflowscausedbymudstonecompactioninthedepressionarea,themineralizationdegree,concentrationsofNa+andCI-,andsalinitycoefficient(SC)increase,whileconcentrationsof(CO32-+HCO3-)andSO42-,metamorphismcoefficient(MC)anddesulfurationcoefficient(DSC)decrease.However,alltheseparametersincreaseinthedirectionofgravity-inducedcentripetalflows.

简介：近几年来，由于在结晶岩内发现了大量油气储量又再度引起了“生物”与“非生物”油气成因说派之间的争议。

简介：EarlyOrdovicianA-typegranitesinthenortheastern(NE)SongnenBlockNEChinawerestudiedtobetterunderstandthegeodynamicsettingsinthisregion.ThisresearchpresentsnewzirconU-PbagesandwholerockgeochemicaldatafortheEarlyOrdoviciangranitesintheNESongnenBlock.ZirconU-PbdatingindicatesthatthegraniteintheCuibei,Hongxing,andMeixiareasintheNESongnenBlockformedintheEarlyOrdovicianwithagesof471-479Ma.ThegranitesshowgeochemicalcharacteristicsofhighSiO2andK2OcompositionsandlowFeOT,MgO,CaO,andP2O5compositions.TheybelongtoahighKcalc-alkalineseriesanddisplayaweakperaluminousfeaturewithA/CNKvaluesof0.98-1.14.TherockshaveaΣREEcompositionof249.98-423.94ppm,andareenrichedinLREEwith(La/Yb)Nvaluesof2.87-9.87,anddisplayobviousEuanomalies(δEu=0.01-0.29).TraceelementsofthestudiedgranitesarecharacterizedbyenrichmentinRb,Th,U,Pb,Hf,andSm,anddepletionofBa,Nb,Ta,andSr.TheydisplaygeochemicalfeaturesofhighZr+Y+Nb+Cevalues(324-795ppm)andGa/AlratiosconsistentwithA-typegranites.Basedonparticulargeochemicalfeatures,suchashighRb/Nb(7.98-24.19)andY/Nb(1.07-3.43),thestudiedA-typegranitescanbefurtherclassifiedasanA2-typesubgroup.ThisresearchindicatesthattheEarlyOrdovicianA-typegraniteswereformedbythepartialmeltingofancientcrustinanextensionalsetting.LowerSr/Yand(Ho/Yb)Nratiosindicatethatplagioclaseandamphiboleareresidualinthesource,andgarnetisabsent,implyingthatthemagmawasgeneratedatlowlevelsofpressure.Bycontrast,thecontemporaneousgranitesintheSEXing'anBlocksuggestasubduction-relatedtectonicsetting,anditsadakiticpropertyindicatesathickenedcontinentalcrust.WesuggestthatthePaleo-AsianOceanplatebetweentheXing'anandSongnenblockssubductednorthwardduringtheEarlyOrdovician.Meanwhile,theNESongnenBlockwasexposedtoapassivecontinentalmargintectonicsetting.

简介：

简介：摘要：目的：探讨集束化护理预防骨科手术后下肢深静脉血栓形成（deepveinthrombosis，DVT）的价值。方法：将2021年1-12月医院实施集束化护理骨科患者228例作为观察组，根据组间性别、年龄、手术时间、身体质量指数等基本资料均衡可比的原则，从2020年1-12月期间选取采用常规护理的骨科患者228例为对照组。观察比较两组患者护理质量及患者相关指标。结果：实施集束化护理后，观察组护理人员DVT理论知识、技能考核、风险评估、预防措施评分高于对照组，差异有统计学意义（P

简介：BlueschistaccompaniedbypeliticschistexposealongtheXinlin-XiguitufaultintheToudaoqiaoarea,northeasternChina.Inthispaper,theblueschistissystematicallystudiedonthepetrographyandmineralchemistry.Theamphibolesintheblueschistarezonedfromwinchitecoretomagnesioriebeckite/glaucophanerimtowinchiteoutermostrim.Thepeakmetamorphicconditionsaredefinedbythemineralassemblageofmagnesioriebeckite/glaucophane,epidote,high-Siphengite(Si<7.1),chlorite,albite,hematiteandquartz,indicatinganepidote-blueschistfaciesmetamorphism.TheP-TconditionsareestimatedasT=350–400℃andP=10-12kbar.TheoccurrenceoftheblueschistalongtheXinlin-XiguitufaultstronglysuggeststhefaultisthesuturebetweentheErgunandtheXing'anblockssituatedintheeasternportionsoftheCentralAsiaOrogenicBelt(CAOB).

简介：江达弧内盆地位于西藏东部,现今被厚约10000m的三叠系所覆盖,三叠纪时该区以海相沉积为主,并以巨厚浊积岩与频繁火山活动形成的钙碱性系列弧火山岩为特征.在露头剖面上,识别出10个三级层序.这些层序共经历了37Ma的时间演化,估算每个层序平均所占时限为3.7Ma.研究认为层序形成的主控因素应是构造-火山、沉积物补给与海平面升降三者之间相互作用过程的响应,其中构造与弧火山作用起决定作用.

简介：TheDiverGasRecoverySystem(DGRS)isanimportantaccessoryequipmentofthe300mSaturationDiveSystem.Thesystemfacilitatestherecyclingofthebreathinggasesfordivers,therefore,ithasgreateconomicbenefits.InApril1995,a300munmannedtestanda100mmannedtestontheHY2031DGRSwerecarriedoutsuccessively.Tenmonthslater,anothermannedtestontheHY2032DGRS

简介：Al-richmetapelitesfromtheMashankhondaliteseriesarecharacterizedbytheassemblageSpl+Grt+Sil+Crd+Bt+Pl(An72)+Kfs+Quartz+graphite.Largeamountsofspinel+quartzassemblagesoccurasinclusionsingarnetandprismaticsillimaniteintheAl-richmetapelitesoftheMashancomplex,NEChina.ThechemicalcompositionofspinelischaracterizedbyZn-rich(XZn=0.33–0.40.XZn=Zn/Zn+Mg+Fe*)(Fe*=Fe2++Fe3+)andFe3+rich(upto0.31p.f.u.).ThecharacteristicchemicalcompositionandthemineralassociationindicatedthattheformationofspinelandquartzassemblagemaybeduetothebreakdownofZn-richstaurolite.ThegeothermobarometersstudiesshowthatthepeaktemperatureoftheMashancomplexisaround820℃andthepeakpressuresis8.0kbar.TheMashancomplexshowsatypicalorogenstyleP-Tpath.

简介：ThemetasedimentaryLujiapuziFormationcropsoutalongthenortheasternmarginoftheNorthChinaCraton,closetotheYan-LiaoRift.Theageandtectonicsettingoftheformation,anditsrelationshipwiththeYan-LiaoRiftarecurrentlyunclear.HerewepresentdetritalzirconU-Pbages,andHfisotopicandgeochemicaldatafortheLujiapuziFormationtoconstrainthetimingofdeposition,theprovenanceoftheformation,andtheregionalstratigraphyrelationship.ZirconU-PbdatingconstrainsthetimingofdepositionoftheLujiapuziFormationtoyoungerthan1780Ma,andindicatesthatmostgrainsweresourcedfromtheLonggangBlockandthePaleoproterozoicLiao-JiBelt.DetailedfieldinvestigationsandacorrelationoftheregionalstratigraphyrevealthatmuchoftheLujiapuziFormationisequivalenttotheTuanshanziFormationintheYan-LiaoRift;thelowersectionmayrepresenttheearliestsedimentsdepositedwithintheFanheBasin.Basedontheseresultsandthefindingsofpreviousstudies,wesuggestthatthebaseoftheChangchengSystemhasanageof1.80Ga.ZirconHfisotopicdataindicatethatthemainperiodofcrustalgrowthalongthenortheasternmarginoftheNorthChinaCratonoccurredat3.2-2.5Ga,withapeakat2.9-2.7Ga.

简介：

简介：随着油气勘探活动的不断加深,国内外相继发现了许多异常压力油气田.研究结果表明,异常压力与油气分布有相关关系.因此,对异常压力的研究,具有举足轻重的意义.作者在广泛收集资料,进行文献系统调研的基础上,详细探讨了异常压力的成因,即异常高压的成因主要有不均衡压实作用、构造作用、水热增压作用、烃类生成作用、液态烃类的裂解作用、粘土矿物的转化作用、浓度差扩散作用、水头、浮力等,而异常低压的成因主要有上覆地层的抬升和剥蚀作用、不同热效应、地下水流动的不平衡作用、封闭层的渗漏作用、岩石扩容作用、浓差作用、气体饱和储集层的埋藏作用等.探讨了异常压力与油气分布的关系.本文对加深异常压力的成因研究,进行合理的钻井和油气生产以及有效的油气勘探工作具有一定的指导作用.

简介：在分析吐哈地区区域应力场性质的基础上，把盆地的形成与发展分为三个阶段。重点阐述各阶段的受力性质、原型盆地类型、沉积环境、沉积厚度及原型盆地的改造。

简介：缝合线是碳酸盐岩中又常见又醒目的一种构造。它的成因有很多假说,流行的是压溶说。笔者重点观察研究了华蓥山煤田和南桐煤田二叠系、三叠系灰岩的缝合线。1.线合线成因缝合线主要由围岩、缝合面、缝合膜三要素组成。围岩是缝合线两侧的岩石;缝合面是围岩溶解凹凸不平的复杂面;缝合膜是由围岩溶解残留物在线合面上聚集压实而成的薄膜。围岩与缝合膜的矿物成分对比如表1。

简介：摘要桥梁的裂缝主要原因，荷载、温度、伸缩、钢筋锈蚀、冻胀、施工等，只要在施工中切实能注意并把握好这几个方面，桥梁的裂缝是可以最大限度的预防和减少的。

简介：大同-阳原盆地的形成演变研究表明，本区最早出现的是将军庙盆地，依次是大同盆地、阳原盆地，直到第三纪末至早更新世初才出现统一的大同-阳原古湖。大同-阳原古湖历时二百余万年，至晚更新世末消亡。新生代以来，大同-阳原盆地火山活动频繁，新构造运动活跃，现在仍是地震灾害的危险区之一。

简介：

简介：森林向大气中排放大量挥发性有机物。森林排放的挥发性有机物的可凝结氧化产物能形成二次有机气溶胶，后者能通过散射太阳辐射和充当云凝结核来影响地球的辐射平衡。但我们对源于生物的挥发性有机物与它们向气溶胶颗粒的转化之间联系的认识仍然有限。