简介:Thecharacteristicsofalaminarwalljetsubmittedtodifferentconfigurationshavebeenexperimentallyexploredinordertoobtainabetterknowledgeoftransitionmodifications,Infactdifferentparameterscanaccelerateordelaythetransitionusingasmoothorroughsurface,heatedornot,submittedtovibrationsornot.Inthisstudy,significanteffectscanbenoticed.Ithasbeenpossibletomeasurethebeginningofgrowthratesofdisturbanceamplitudeusingawindtunnelandcomparingtheresultswiththelinearstabilitytheory.
简介:Theexactclassicallimitsforthecoefficientofvariationcforthenormaldistributionarederived.Thehand-calculatingapproximatedclassicallimitsforchavinghighaccuracyaregiventomeetpracticalengineeringneeds.UsingOdehandOwen’scomputationalmethodandBrent’salgorithm,thetablesforther-upperexactclassicallimitsofcoefficientofvariation.fornormaldistributionarecalculatedforthedifferentconfidencecoefficientγ,thesamplesizen=I(1)30,40,60,120,thesamplecoefficientofvariation(?)=0.01(0.01)0.20.Itisshownthatifn≤8,(?)≤0.20,thentheY-upperexactclassicallimitscuforcareslightlyhigherthantheexactfiduciallimitscu,Fforc.ifn>8,(?)≤0.20,thencu-cu,F<5×10-6.
简介:这篇文章讨论北方大西洋摆动(NAO)和诺思太平洋摆动(NPO)的interannual变化,它与在与气候被联系的中国的interdecadal气候变化的关系在1960鈥檚在北半球跳,用数据分析。两个都,NAO和NPO的振幅在1960鈥檚显然增加,这清楚地被显示出,摆动的主要时期在1960鈥檚前从3-4年改变到8鈥?在1960鈥檚以后的5年。因此,在中国的interdecadal气候变化或气候在1960鈥檚跳仔细与NAO和NPO的异例有关。关键词诺思大西洋摆动(NAO)-诺思太平洋摆动(NPO)-气候跳-Interdecadal气候变化这个工作被国家关键基本科学节目在中国(G1998040903)支持,科学的中国学院和中国(资助No.49823002)的国家自然科学Fundation。作者对为打手稿的王璇女士也感激。
简介:Knowledgeoftheevolutionofpathogensisofgreatmedicalandbiologicalsignificancetotheprevention,diagnosis,andtherapyofinfectiousdiseases.InordertounderstandtheoriginandevolutionoftheSARS-CoV(severeacuterespiratorysyndrome-associatedcoronavirus),wecollectedcompletegenomesequencesofallvirusesavailableinGenBank,andmadecomparativeanalyseswiththeSARSCoV.GenomicsignatureanalysisdemonstratesthatthecoronavirusesalltaketheTGTTastheirrichesttetranucleotideexcepttheSARS-CoV.Adetailedanalysisoftheforty-twocompleteSARS-CoVgenomesequencesrevealedtheexistenceoftwodistinctgenotypes,andshowedthattheseisolatescouldbeclassifiedintofourgroups.OurmanualanalysisoftheBLASTNresultsdemonstratesthattheHE(hemagglutinin-esterase)geneexistsintheSARS-CoV,andmanymutationsmadeitunfamiliartous.
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简介:A6-layer,4°×5°horizontalresolutionglobaloceanmodelhasbeendesignedandimproved.Aftera100-yearin-tegration,anequilibriumstatehasbeenreachedfromtheuppertolowerlayers.Bytakingthemeanstateoflastl0mod-elyearsasclimaticstate,weanalyzedthecharacteristicsoftheseasonalvariationinourmodelintegration.Theresultsshowthatthesimulatedseasonalvariationissimilartotheobserved.Sothedesignofourmodelissuccessful.Then,us-ingthesimulatedclimaticstateoftheseasonalvariationastheinitialstate,andtheobservedstressandthermalstateastheatmosphericforcing,wesimulatedtheprocessofElNinoin1972—1973successfully.Thesimulatedresultsofsea-sonalvariationusingourmodelwillbepresentedinpartI.
简介:ByusingtheobservationalO3dataofKunmingandHongKongduringtheperiodof1997-2001,thepaperstudiesthedistributionandvariationoftotalozoneinlowlatituderegionofChina.ThestudyshowsthatthecharacteristicsofvariationinKunmingandHongKongareverysimilar,andthetotalozoneinthewesternareasislargerthanintheeasternones.Itismaximuminsummerandminimuminwinter.
简介:ModellingtheInterannualVariationofRegionalPrecipitation over ChinaWangHuijum(王会军)(LASG,InstituteofAtmosphericPhysics,ChineseA...
简介:通过对分布于欧洲的水青冈(Fagussylvatica和Fagusorentalis)和亚洲的水青冈(Fagusjaponica,Faguscrenata,Faguslucida,Fagusengleriana和Faguspashanica)的地理历史资料分析和凝胶电泳法等位酶的测定,探讨欧亚大陆水青冈地理变异和遗传多样性.所测定的酶系统包括:过氧化物酶(PX1和PX2)、磷酸葡萄糖脱氢酶(PGD)、酸性磷酸化酶(ACP1和ACP2)、超氧化物歧化酶(SOD)、谷氨酸草酰乙酸转氨酶(GOT1,GOT2和GOT3)、异柠檬酸脱氢酶(IDH)、磷酸果糖异构酶(PGI)、甲基萘醌还原酶(MNR)、葡萄糖磷酸变位酶(PGM1和PGM2)和苹果酸脱氢酶(MDH1和MDH2)10种酶系统.测定和分析了水青冈遗传相似性、固定指数及遗传多样性随经度、纬度和海拔高度的变化规律,讨论了水青冈起源和分布特点,为进一步研究水青冈的种间关系和地理历史进化过程提供了科学依据.
简介:广州春天降雨主要展出内部年变化30年的ofQuasi每年两次、内部的十的变化,并且在时间放大的弱降雨atinterdecadal的时期。Nino3的SST异例(SSTA)是Guangzhouspring降雨的最强壮的先锋。他们从以前的11月有重要积极关联并且稳定地坚持到4月。在以前的冬季的Nino3SSTA在春天通过NorthPacific副热带的高、低的风影响广州春天降雨。当Nino3SSTA在以前的冬季是积极的时,跳副热带的高度是强烈的,向西,华南位于在搬运到华南的副热带的高度,和水汽的边登上气流的区域被反气旋循环加强到菲律宾的东方。广州春天降雨因此是重的。当Nino3SSTA是否定的时,副热带的高度弱、东方,华南从副热带的高度是遥远的并且位于下气流的区域,并且因为低级气旋的循环控制区域到菲律宾的东方,北方风在华南占优势,搬运到华南的水汽是弱的。广州春天降雨因此是弱的,春天干旱被结果。
简介:Spatialandtemporalvariationof gravity fieldinthecapitalregionChang-CaiHUA;(华昌才)YongGUO;(果勇)Duan-FaLIU;(刘瑞法)GangXIAO;(肖钢),J.T....
简介:A2-Dglobalchemistry-transportmodelissetupinthispaper.Themodelsimulatestheatmosphericozonedistributionswellwithspecifieddynamicalconditions.Theanalysisofozonevariationmechanismshowsthatozoneischemicallyinquasi-equilibriumexceptforthepolarnightregionwherethevariationofozoneconcentrationisunderthecontrolofdynamicalprocesses,thattheoxygenatomswhichproduceozonearemainlyprovidedbythephotolysisofO2intheupperstratosphereandbythephotolysisofNO2inthelowerstratosphereandthetroposphere.andthattheozoneisdestroyedmainlybyNOx:thereactionsbetweenNOxandO3andtheoddoxygencyclecontribute80%tomorethan90%oftheozonedestruction.
简介:StudyofthemajorAsianriversdischargetotheoceanrevealsvariationsoftheirwaterdischargesandsedimentloads,andlocalcharacteristicsofriversedimentconcentrations.Onthebasisofthis,theAsianriversfallintothreeregions,includingEurasiaArctic,EastAsia,SoutheastandSouthAsiaRegions.TheEurasiaArcticRegionischaracterizedbythelowestsedimentconcentrationandload,whiletheEastAsiaRegionisofthehighestsedimentconcentrationandhighersedimentload,andtheSouth-EastandSouthAsiaRegionyieldshighersedimentconcentrationandhighestsedimentload.Thesedimentloadsoftheseregionsaremainlycontrolledbyclimate,geomorphologyandtectonicactivity.TheEurasiaArcticriverswithlargebasinareasandwaterdischarge,drainlowreliefwhichconsistsoftundrasediment,thuscausingthelowestsedimentload.TheEastAsiariverswithsmallbasinareasandlowestwaterdischarges,drainextensiveloessplateau,andtransportmosterodibleloessmaterial,whichresultsinhighestsedimentconcentration.TheSEandSouthAsiariversoriginatingfromtheTibetPlateauhavelargebasinareasandthelargestwaterdischargesbecauseoftheSummerMonsoonandhighrainfallinfluence,causingthehighestsedimentload.InAsia,tectonicmotionoftheTibetPlateauplaysanimportantrole.ThoselargeriversoriginatingfromtheTibetPlateautransportabout50%oftheworldriversedimentloadtooceanannually,forminglargeestuariesanddeltas,andconsequentlyexertingagreatinfluenceonsedimentationinthecoastalzoneandshelves.
简介:Inthispaper,thefollowingcontentsincludingtheoriginalreceptorEI213andothertwocontrolmaterials,RAPDpolymorphism,photosyntheticefficiency,andthenumberofvascularbundlesofthefirstinternodesbelowthepedunclehavebeenstudiedfortheeightF7transgeniclinesobtainedfromionbeamimplantation.Theresultsshowedthattherewasasignificantvariationingenomesofmaize-riceline,comparedwiththereceptorEI213,afterthetotalexogenousmaizeDNAwasintroducedintoEI213.Thenumberofthevascularbundlesofmaize-riceprogeny'slineswasobviouslymuchlargerthanthoseoftheoriginalreceptorEI213andothertwocontrolsGER-3andMH63,andalongwiththephotosyntheticefficiencyofmaize-riceprogeny'slinesbeinggoneup.Moreover,theparenchymacellsaroundthevascularbundlesofthetransgeniclinesbecamemuchlargerinnumberandinsizethanthosearoundthecontrols.Alltheseindicatedthatthemaize-riceprogeny'slinesarereallydifferentfromandsuperiortothereceptorandthecontrols.ItisanovelandusefulwaytoapplyionbeamimplantationintransferringDNAfromC4plantmaizeintoC3plantrice.
简介:本文对4个地点的毛白杨无性系进行了木材纤维长度遗传变异的研究.结果表明木材纤维长度在地点和无性系水平上均有显著的差异.木材纤维长度的无性系重复力估计为0.79,表明这一材性性状受到较强的遗传控制,可以通过遗传手段得到改良.本文还研究了木材纤维长度在株内的遗传变异.木材纤维长度以及其它性状间的相关分析发现木材纤维长度和树木生长性状(包括材积、树高、胸径和树干通直度)之间均呈显著的正相关关系,但在木材纤维长度和木材基本密度之间存在显著的负相关关系.研究结论认为根据不同地点生长速率与材性的关系,可以进行以生长性状或木材材性性状为主的选择,也可以进行两方面的联合选择.
简介:Atheoreticalresearchonthevariationoftheabsorptionanddispersionprofilesandpopulationdistributionofeachlevelinaladder-four-levelsystemdrivenbytwocoherentfieldshasbeenmade.Whetherthevariationoccursornotdependsontheeffectofquantuminterference,thedetuningoftheuppercoherentfieldandtheseparationofthetwointermediatelevels.Adressed-stateanalysisisintroducedtoexplainthenumericalresults.
简介:ThecontentsanddistributionsofCaCO3,Fe2O3.FeOandfreeFe2O3intheWeinanloesssectionofShaanxiProvinceofChinawereinvestigatedthroughdensesampling.TheresultsshowthatthecontentsofCaCO3andtherationofFe2O3/FeOmaybechosenasproxyindicesfortheprecipitationandtemperaturechangesintheformationtimeofthestrata,respectively.Accordingtothesegeochemicalindices,sixstagesofplaeoclimateevolutionareproposedinthisregionsince142kaB.P.,andsecondaryclimatechangesarediscussedaswellbasedonthecurvesofgeochemicalindices.