简介:Inordertostudythespatiotemporalevolutionoftheprecursoryanomalies10yearsbeforetheWenchuanMS8.0earthquakein2008,theepicentraldistanceoftheprecursoryanomaliesiscalculatedbyusingthegeometriccenteroftheruptureregionandtheellipticalcenterlineoftheaftershockregion.Theresultshows,precursoranomaliesgraduallyincreasedabout2yearsbeforetheWenchuanearthquake.Theratioofabnormalitemsisgreaterthan25%inthenearsourcearea(abouttwicethesourcescale)and17%-24%intheremotearea(about3-5timesthesourcescale).Therearethreedifferentstagesofspatiotemporalevolutionofprecursoryanomalies.Duringtheαstage(includingα1andα2,between700to3000daysbeforethemainearthquake),theanomaliesaremainlydistributedinthesouthwestandnorthwestareaoftheWenchuanaftershocksarea.Itisshownthattheprecursorsofthefarsourceregionandthenearsourceareahavethecharacteristicsofoutwardexpansion.Duringtheβstage(between300to700daysbeforethemainearthquake),theanomaliesaredistributedinthesouthwestandnorthernregionoftheaftershockregion,showingalargerangeofanomalies.Duringtheγstage(includingγ1andγ2,300daysbeforethemainearthquake),therangeofanomalydistributioniswide,andtheanomaliesaredistributedinthesouthwestandnortheastoftheaftershockarea.Theanomaliesconvergedtoepicenter(γ1)inthefarsourceregionandexpandoutwards(γ2)inthenearsourceregion.Resultsoftheexperimentalstudyandmechanicalanalysisofearthquakepreparationprocessindicatethatthethree-stagecharacteristicsofprecursoryanomaliesintheprocessofearthquakepreparationmaybecontrolledbytheseismogenicbody,whichisaformofexpressionintheprocessofearthquakepreparationandauniversalfeatureduringtheearthquakepreparationprocess,whichhasacertainguidingroleinearthquakeprediction.
简介:摘要本文采取电感耦合等离子体质谱仪,对纯钨制品中的19种杂质元素进行实验检测,得到检测方法较为准确和结果可靠的实验效果。
简介:目的比较神经髓鞘和脱脂神经髓鞘诱导多发性硬化(MS)T淋巴细胞系(TCL)对11种神经髓鞘成份的增殖反应.方法以2种人神经髓鞘在体外二次致敏,诱导MS-TCL和正常人TCL,用MBP、PLP及其合成多肽等抗原检测PTL的增殖反应.结果与非脱脂TCL相比,脱脂髓鞘使MS组的免疫反应性显著改变.尤其对PLP6种多肽反应性的改变有统计学差异,总平均阳性孔比较P<0.001(3.41±4.83vs5.49±5.31).结论髓鞘脱脂使MS组增殖反应显著增加,二组的差别更明显.提示在髓鞘脱脂方面MS和正常人反应的异质性,此点对理解MS的病理机制可能很重要.
简介:建立起HNO3-H2O2-HF体系微波消解前处理样品,利用电感耦合等离子体质谱(ICP—MS)同时测定土壤中的铬(Cr)、镍(Ni)、铜(Cu)、砷(As)、铊(Tl)、铅(Pb)6种重金属元素含量的方法。该方法的相关系数在0.9996~1.000,相对标准偏差在0.669%~3.02%,加标回收率为94.68%~115.5%,检出限为2.004~312.4ng/L,结果表明该方法满足重金属分析的要求。用建立起的方法测定了来自湖南、湖北、云南、贵州、河南、福建、辽宁7个省45个产区烟田土壤中的Cr、Ni、Cu、As、田和Pb6种重金属元素含量;与对应烟叶中的6种重金属含量相比,聚类分析结果表明不同省区间土壤中的重金属含量无明显差异,而烟叶中却差异明显。
简介:TheYutianearthquakewithM_S7.3happenedonFebruary12,2014.Theprecursormonitoringabilityisweakinthatarea.Wefoundtendencyanomaliesandmiddle-andshort-termanomaliesfrommetalpendulumtiltmeasurementsinHotanseismicstationbeforetheearthquake.AndwealsocomparedtheanomalieswiththatoftheM_S7.3YutianearthquakeonMarch21,2008.Thetendencyanomaliesmeasuredbythemetalpendulumtiltmeterappearedsince2012astiltingeastward.Whilethemiddle-andshort-termanomalieswerecharacterizedbyacceleration,pauseandrapidchangeoftiltrateintwodirections.Thetendencyanomaliesofmetalpendulumtiltrecordsarethesamebeforethetwoearthquakes.Theybothhappenedintheeastdirection.However,therearedifferencesinduration,characteristicandearthquakeintervalsforthemiddle-andshort-termanomalies.
简介:UsingthedigitaltelemetricseismicwaveformdataofChengduandKunming,thisarticlestudiesthefocalmechanismsolutionsandtheapparentstressvaluesofalargenumberofsmallearthquakes,andthenanalyzesthedynamicvariationofregionalstressfieldsandthespatio-temporaldistributionofapparentstressvalues.TheannualvariationvaluesoftheazimuthofaverageprincipalstressfieldbeforetheMay12,2008M_S8.0WenchuanearthquakeintheSichuan-Yunnanregionwere58°from2003to2004,85°from2003to2005,61°from2006to2007and90°from2006toApril2008respectively.Inrecentyears,deflectionordisturbancesoccurredintheazimuthoftheaverageprincipalstressfieldintheSichuan-Yunnanregion.AnalysisshowsthatthismayberelatedtothechangeofstressfieldstatesofcrustalblocksbeforeandaftertheDecember26,2004M_S9.0Sumatraearthquakeandthe2008M_S8.0Wenchuanearthquake.Theratioofthrust-typeearthquakesintheSichuan-Qinghaiblockwasonthehighersideintheperiodfrom2006to2007,andthesourcefaultingtypeoftheregionalmoderateandsmallearthquakeshadchangedbeforetheM_S8.0Wenchuanearthquake.ThechangeofstateofthestressfieldisconsistentwiththechangesinblockdisplacementfieldsrevealedbyGPSdataandthecrustalshorteningvelocityverticaltotheLongmenshanfaultzone.Basedontheradiationenergycalculatedfromallbandsoftheseismicwaveform,thevalueofapparentstressσ_appisobtained.Thefluctuationshapeofthefittingtrendoftheapparentstressisrelatedtotheintensityofregionalseismicity.Itrevealsthatthemicro-dynamicfluctuationprocessoftheregionalstressvalueissimilartotheazimuthtransitionoftheregionalprincipalcompressivestressfield,whichcanbeusedtoprobeforpregnantphysicalprocesses.Areaswithahighervalueofapparentstressσ_apparepossibleareasofpotentialseismicrisk.Itcanbeseenfromthespatialdistributionofthemediumandshort-termapparen
简介:Aftertheoccurrenceofanearthquake,strongmotionobservationnetworkscanrecordgroundmotionatdistributedobservationstations.Basedonthegroundmotionparametersfromtheserecords,thespatialdistributionofseismicintensitycanbequicklydetermined,andthedegreeofdamageindifferentareascanbeestimated.Thisinformationprovidesthetechnicalbasisfortheemergencyresponse,soastoensurethatrescueteamscanreachextremeearthquakeareasandcarryoutthesearchandrescueoperationinanaccurateandtimelymannertoreducecasualtiesandpropertyloss.Inthispaper,weintroduced7intensityalgorithmsandcomparedtheresultswiththerecordsoftheJiuzhaigouMS7.0earthquake.Wefoundthatthedifferencesbetweentheinstrumentalintensitiescalculatedbyeachmethodandthemacrointensitieswerewithina1-degreerange,whichsuggestedgoodpracticalityofthesedifferentmethods.Theresultscalculatedbytheindustrialstandards-basedcalculationmethodandtheintegratedtestshowedgoodconsistency.
简介:TheWenchuanMS8.0earthquakeoccurredontheLongmenshanfaultwhichinclinesatadipangleexceeding60degrees.Sincemostthrustearthquakesoccuronfaultswithdipanglesofabout30degrees,itisenigmaticwhytheWenchuanearthquakeoccurredonsuchasteepfault.InthisstudyweuseasimplefiniteelementmodeltoinvestigatehowthestressstateinthefaultchangeswiththevariationofPoisson’sratio.Theresultsshowthat,withthePoisson’sratiointhefaultincreasing,themagnitudesoftheprincipalstressesincreaseandthemaximumshearstressdecrease,and,especially,theanglebetweenthemaximumprincipalstressandthefaultplanedecreases,whichwillenhancethedrivingforcetoovercomethefrictionalresistanceonthefault.TheincreaseofPoisson’sratiointhefaultmaybeanimportantfactortoaffecttheoccurrenceofthefaultearthquakeswithlargeanglesbetweenmaximumprincipalstressandfaultplane.
简介:Inthispaper,statisticsaretakenontheco-seismicresponseofundergroundfluidinYunnantotheNepalM_S8.1earthquake,andtheco-seismicresponsecharacteristicsofthewaterlevelandwatertemperatureareanalyzedandsummarizedwiththedigitaldata.TheresultsshowthattheNepalM_S8.1earthquakehadgreaterimpactontheYunnanregion,andthemacroandmicrodynamicsoffluidsshowedsignificantco-seismicresponse.Theearthquakerecordingcapacityofwaterlevelandtemperaturemeasurementissignificantlyhigherthanthatofwaterradonandwaterqualitytothislargeearthquake;themaximumamplitudeanddurationofco-seismicresponseofwaterlevelandwatertemperaturevarygreatlyindifferentwells.Thechangingformsaredominatedbyfluctuationandstepriseinwaterlevel,andarisingorfallingrestorationinwatertemperature.Fromtherecordsofthemainshockandthemaximumstrongaftershock,wecanseethatthegreatermagnitudeofearthquake,thehigherratiooftheoccurrenceofco-seismicresponse,andinthesamewell,thelargertheresponseamplitude,aswellasthelongertheduration.Theamplitudeanddurationofco-seismicresponserecordedbydifferentinstrumentsinasamewellaredifferent.Watertemperatureco-seismicresponsealmostoccurredinwellswithwaterlevelresponse,indicatingthatthewellwaterlevelandwatertemperaturearecloselyrelatedinco-seismicresponse,andthewellwatertemperatureseismicresponsewascausedmainlybywellwaterlevelseismicresponse.
简介:目的建立ICP-MS同时测定红参中8种元素含量的分析方法.方法硝酸-高氯酸体系进行湿法消解,ICP-MS分析,同时分析锰、铜、锌、钡、钴、铁、镍、鎘8种元素.结果该方法线性范围宽,Mn、Cu、Zn、Ba、Co、Fe线性在0μg/L~500μg/L之间,Ni、Cd线性在0μg/L-100μg/L之间,线性相关系数0.9847~0.9999之间,检出限在0.0007~0.02mg/Kg之间.标准物质的RSD在4.45%~9.13%之间.结论利用该方法对标准物质茶叶中Mn、Cu、Zn、Ba、Co、Fe、Ni、Cd含量进行测定,表明该方法能够满足上述8种元素的分析要求.将方法应用于4、5年生红参中8种元素含量水平测定,获得了较满意的分析结果.