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简介：Thedemographicstructureofpopulations,particularlyageandsex,hasprofoundconsequencesforharmoniousandsustainablesocialandeconomicdevelopment.Furthermore,analyzingsexratiosofpopulationsisimportantinanalyzingthedevelopmentofthestatusOfwomenandgirls.

简介：ＡｇｅＳｔｒｕｃｔｕｒｅａｎｄＤｅｐｅｎｄｅｎｃｙＲａｔｉｏＣｈｉｎａ’ｓｐｏｐｕｌａｔｉｏｎｈａｓｅｘｐｅｒｉｅｎｃｅｄａｐｒｏｃｅｓｆｒｏｍａｈｉｇｈｂｉｒｔｈｒａｔｅａｎｄｈｉｇｈｍｏｒｔａｌｉｔｙｒａｔｅｔｏａｌｏｗｂｉｒｔｈｒａｔｅａｎｄｌ...

简介：Sincethe1980s,especiallythemid-1980s,theimbalanceinthesexratioatbirthinChinahasbeenincreasingcontinuouslyandthesituationhasworsenedinrecentyears,accordingtothefourthandfifthcensusesin1990and2000.Thisissuehasdrawnwidespreadattentionfromthegovernmentaswellasacademia.Thefundamentalreasonfortheimbalance

简介：Inthisarticlethenotionofquasi-symmetryisintroduced.ItisprovedthatthequasisymmetryisequivalenttotheuniquenessofinvariantmeasureofLevyprocessesinsomesenseMoreover,therelationshipbetweenratiolimitsandinvariantmeasuresisstudied.

简介：Byanalogueexperimentofexhaustgas,thesensitivecharacteristicsoftitaniatoair/fuelratiowasinvestigated.Theeffectsofsomeimpuri-tiesontheelectricconductivityofTiO2,thedeviationof（A/F）cfrom（A/F）sinnonequilibriumgassystemandtheself-catalyticoxidationofTiO2wereexplainedrespectively.Theeffectsofca-talyst,porosityandthicknessofsensorelementontheresponsetimewasalsoanalyzed.

简介：ThecircumfluencearoundtheJiuduanSandbankisthoroughlystudiedbymeansoftheprinci-pleofleastresistanceinfluiddynamics.ThediversionratiooftheNorthChannelfor1998iscalculated,whichisalmostthesameasthefieldsurveydata.ThenormalandminimumdiversionratiosoftheNorthChannelafterstagesⅠ,ⅡandⅢregulationworksaswellasthefuturephaseareobtained.Thenumeri-calresultsandpredictedvalueareaccurate.

简介：Itiswidelyknownthattheseismicresponsecharacteristicsofasoilsitedependsheavilyonseveralkeydynamicpropertiesofthesoilstratum,suchaspredominantfrequencyanddampingratio.Awidelyusedmethodforestimatingthepredominantfrequencyofasoilsitebyusingmicrotremorrecords,proposedbyNakamura,isinvestigatedtodetermineitseffectivenessinestimatingthedampingratio.TheauthorsconductedsomemicrotremormeasurementsofsoilsitesinHongKongandfoundthatNakamura'smethodmightalsobeusedtoestimatethedampingratioofasoilsite.DampingratiodatafromseveraltypicalsoilsiteswereobtainedfrombothNakamura'sratiocurvesusingthehalfpowerpointmethodandresonantcolumntests.Regressionanalysisindicatesthatthereisastrongcorrelationbetweenthedampingratiosderivedfromthesetwodifferentapproaches.

简介：Inordertosearchforthemeasuretoincreasetheenergydissipationratioofsteppedspillways,somemaininfluencingfactorsfortheenergydissipationratioofsteppedspillways,suchasunitdischarge,damslope,heightofstepandsoon,werestudied.Theresultsshowthattheenergydissipationratiodecreaseswiththeincreaseintheunitdischargeandincreasesastheslopebecomesgentle.Theeffectsofstepheightontheenergydissipationratioarecloselyrelatedtounitdischarge.Iftheunitdischargeissmaller,thechangeofenergydissipationratiowithstepheightbecomesgreater.While,iftheunitdischargeisgreater,theinfluenceofstepheightonenergydissipationratioisverylittle.Accordingtothedistributionsoftheturbulencekineticenergyandturbulencedissipationrateobtainedbynumericalsimulation,thebasicreasonofthedecreaseofenergydissipationratiowiththeincreaseintheunitdischargewasdiscussedandsomespecificmeasurestoincreasetheenergydissipationratioweresuggested.

简介：Inthispaperweconsidersomerelatednegativehypergeometricdistributionsarisingfromtheproblemofsamplingwithoutreplacementfromanurncontainingballsofdifferentcoloursandindifferentproportionsbutstoppingonlyaftersomespecificnumberofballsofdifferentcolourshavebeenobtained.Withtheaidofsomesimplerecurrencerelationsandidentitiesweobtaininthecaseoftwocoloursthemomentsforthemaximumnegativehypergeometricdistribution,theminimumnegativehypergeometricdistribution,thelikelihoodrationegativehypergeometricdistributionandconsequentlythelikelihoodproportionalnegativehypergeometricdistributiuon.TotheextentthatthesamplingschemeisapplicabletomodellingdataasillustratedwithabiologicalexampleandinfactmanysituationsofestimatingBernoulliparametersforbinarytraitswithinafinitepopulation,theseareimportantfirst-stepresults.

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简介：ＴｈｅｐｈｙｓｉｃａｌｉｍｐｌｉｃａｔｉｏｎｏｆｃｏｄａａｍｐｌｉｔｕｄｅｒａｔｉｏａｎｄｉｔｓｐｏｓｓｉｂｌｅａｐｐｌｉｃａｔｉｏｎＴＩＡＮ－ＺＨＯＮＧＺＨＡＮＧ（张天中）ＹＵＮ－ＳＨＥＮＧＭＡ（马支生）ＲＯＮＧ－ＬＩＡＮＧＨＵＡＮＧ（黄蓉良）Ｉｎ...

简介：1.IntroductionThemethodoflikelihoodintroducedbyFisheriscertainlyoneofthemostcommonlyusedtechniquesforparametricmodels.Recentlythelikelihoodhasalsobeenshowntobeveryusefulinnonparametriccontexts.O...II--31hasintroducedempiricallikelihoodratiostatistics...

简介：ByECHunderasteadyB_vfield,aclosedfieldequilibriumofalowaspectratioaslowasR/a=1.4isspontaneouslyformedintheLATEdevice.Afterthespontaneousformation,theplasmacurrenthasincreasedfurtheruptoI_P=7.2kAby2.45GHz,30kWandI_P=11kAby5GHz,120kW,byincreasingthemicrowavepowerwithaslowrampofB_vfortheequilibriumoftheplasmaloopatlargercurrents.Bothamountto12%ofthetotaltoroidalcoilcurrent.ECH/ECCDat2udharmonicresonanceofEBWsupportstheplasma.Anoutlineofthetheoreticalconsiderationsfortheformationprocessispresented.

简介：AnewconceptaboutthenextsteptokamakdeviceisrecentlyproposedbyacademicianLIZhengwu.HeindicatedthandevicewiththeaspectratioAnear2isablankinboththepresent-daytokamakdevicesandtheproposedorinconstructiontokamaks,includingtheITER-FEAT.

简介：Adelayedsemi-ratio-dependentpredator-preysysteminaperiodicenvironmentisinvestigatedinthispaper.ByusingacontinuationtheorembasedonGainesandMawhin'scoincidencedegree,theglobalexistenceofpositiveperiodicsolutionisstudied.Asetofeasilyverifiablesufficientconditionsareobtained.

简介：INTRODUCTIONItiscommonknowledgethatthedevelopmentandoccurrenceofanearthquakeisaverycomplicatedgeophysicalprocess.Anearthquakeiscausedbythelocalfailureoftheearthcrustmedium,andearthquakesaredistributedinhomogeneouslyinspace.Seismicactivities,however,arearealreflectionoftheinteractionofthefaults,whichprovidesussomeinformationconcerningtheearthcrustmediumandmayhelpuspredicttheearthquake.Therefore,thestudyoftheseismicitypatterncanbecomeameansofearthquakeprediction.Inordertoreflectdirectlythespacialdistributionofseismicactivities,thesketchofepicentraldistributionhasbeenwidetyusedinthestudy

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简介：Anumericaldesignonthetriangularphotoniccrystalfiber(PCF)basedbackwardmulti-pumpRamanamplifierispresented.ItisdemonstratedthathighflatRamangaincanbereachedbasedonPCF.InfluencesofdifferentgeometricparametersandgermaniumdopingconcentrationsontheRamannetgain,amplifiedspontaneousemission(ASE)noiseanddoubleRayleighbackscattering(DRBS)ofthesignalhavebeenanalyzed.ForoptimizingcrystalfiberRamanamplifier(FRA),thereistradeoffbetweenthegeometricparameterandgermaniumdopingconcentrationoftriangularPCF.TheresultsshowthatPCFisanappropriatecandidateforhighgainRamanamplifiers.

简介：Thevariationinload/unloadresponseratiobeforesomemoderateearthquakesisanalyzedbasedonthetheoryoftheload/unloadresponseratio.Theresultsshowthattheload-unloadresponseratioincreasesnoticeablybeforemoderateearthquakes,andtherearethreekindsofpatternsinwhichtheload/unloadresponseratiovariesandthedurationofnoticeableincreaseinload/unloadresponseratiorangesfromhalfayeartotwoyears.