简介:Thedynamicshearmodulusratioanddampingratioofsandygravelareimportantparametersfortheseismicresponseanalysisofvalleygeomorphicsites,whichhaveanimportantimpactonthedeterminationofdesigngroundmotionparameters.Inthispaper,thedynamictriaxialtestofsandygravelshasbeenperformedbasedontheprojectoftheShangluoSeismicMicrozonation.Combinedwiththeotherresultsofsandygravel,therecommendedresultsofslightlydense,mediumdenseanddensesandygravelwereobtained.Bybuildingthetypicalsitemodel,theinfluenceofthedynamicshearmodulusratioandthedampingratiouncertaintyontheseismicresponseofthesiteisstudied.Theresultsshowthattheuncertaintyoftheaverageofthedynamicshearmodulusratioandthedampingratio±1timesthestandarddeviationhaslittleeffectonthepeakaccelerationofthesandygravelsite,andtherationalityofthegroupingandstatisticalresultsisexplained.Underdifferentprobabilitylevels,thechangeintheshearmodulusratioanddampingratioleadstoasignificantdifferenceinthehighfrequencyresponsespectrum.Theresponsespectrumof0.04-0.1srangesfromabout20%,butithaslittleeffectonthelongperiodspectrumofmorethan1.0s.Thestudyofdynamicshearmodulusratioanddampingratioofsandygravelhastheabilitytoimprovethereliabilityofthedesigninggroundmotionparameters.
简介:AgeStructureandDependencyRatioChina’spopulationhasexperiencedaprocesfromahighbirthrateandhighmortalityratetoalowbirthrateandl...
简介:数据包封分析(DEA)和比率分析(RA)是为测量单位生产率和能基于可得到的输入和输出变量被估计的任何另外的标准的二个广泛地使用的方法。很多个研究人员学习了DEA和RA并且注意了他们之间的积极、否定的差别。聚集的比率分析(ARA)模型,提供在DEA和RA理论之间的一个重要连接,等价于CCRDEA模型,并且这个等价性质为以不同方法要解释并且适用的DEA提供很多机会。这份报纸扩大ARA模型的结果并且建议一个扩大聚集的比率分析(EARA)模型,象到在DEA上下文的电子消息传输方式模型的从CCR模型的发展类似。建议模型能提供卓见进回来的特征可伸缩,作为电子消息传输方式模型起相应作用。数字例子在纸被重游,结果被比较。
简介:Sincethe1980s,especiallythemid-1980s,theimbalanceinthesexratioatbirthinChinahasbeenincreasingcontinuouslyandthesituationhasworsenedinrecentyears,accordingtothefourthandfifthcensusesin1990and2000.Thisissuehasdrawnwidespreadattentionfromthegovernmentaswellasacademia.Thefundamentalreasonfortheimbalance
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:灵活圆形的柱体的导致流动的颤动(FIV)上的集体比率的效果试验性地在一辆拖引的坦克被调查。分别地,有7.9公里和4.8公里的外部、内部的直径的一个Tygon试管为学习被采用。试管被连接到一辆马车并且从休息拖引到一稳定在慢下来在1.6m的距离上再休息在前加快m/s到1.6仍然流水。雷纳兹数字基于柱体,外部直径是80013,000,并且减少的速度(柱体天赋频率使正常化的速度和外部直径)从2~25跨越了。当连接时,柱体在11N的轴的虚荣下面从420公里被伸长到460公里。把伸长的长度基于柱体,方面比率(到外部直径的柱体长度的比率)作为58被计算。三集体比率(柱体的比率结构的质量到代替的液体质量,m*)被分别地用空气,水,和合金粉末(nickel-chromium-boron矩阵合金)填满柱体内部0.7,1.0,和3.4决定。一个光方法为反应大小被采用。多频率颤动在两个被观察同轴(IL)并且跨流动(CF)回答;在高级雷纳兹数字,颤动模式直到3rd在CF反应被识别。模式转变被发现为最高测试的集体比率在更低的减少的速度发生。颤动振幅和频率关于减少的速度被确定并且表示。一个重要减少的颤动振幅与增加集体比率在IL反应被发现,并且仅仅起始、上面的分支在IL和CF反应振幅存在。规范的反应频率被揭示线性地关于减少的速度增加,并且为线性关系的斜坡被发现为测试的三格相同。
简介:Inthispaperweconsidersomerelatednegativehypergeometricdistributionsarisingfromtheproblemofsamplingwithoutreplacementfromanurncontainingballsofdifferentcoloursandindifferentproportionsbutstoppingonlyaftersomespecificnumberofballsofdifferentcolourshavebeenobtained.Withtheaidofsomesimplerecurrencerelationsandidentitiesweobtaininthecaseoftwocoloursthemomentsforthemaximumnegativehypergeometricdistribution,theminimumnegativehypergeometricdistribution,thelikelihoodrationegativehypergeometricdistributionandconsequentlythelikelihoodproportionalnegativehypergeometricdistributiuon.TotheextentthatthesamplingschemeisapplicabletomodellingdataasillustratedwithabiologicalexampleandinfactmanysituationsofestimatingBernoulliparametersforbinarytraitswithinafinitepopulation,theseareimportantfirst-stepresults.
简介:第二与雄激素受体(AR)的敏感为出生前的睾丸激素和covaries作为通常认为的biomarker被建议了到第四位比率(2D:4D)。出生前的睾丸激素和AR在阴茎生长起一个中央作用。在这研究,我们调查了在位比率和阴茎长度之间的关系。在一个单个第三级的学术中心为urological外科被就医的朝鲜的人在这被检查给了知情同意的20岁以上的学习,和144个人有希望地被注册。右边的秒位和第四位的长度被一个单个调查者在阴茎长度的测量以前测量。在麻醉下面,松驰、拉长的阴茎长度被另一个调查者测量没测量也不有任何东西关于位长度的信息。用线性回归模型的Univariate和multivariate分析证明那唯一的高度是为松驰的阴茎长度的一个重要预兆的因素(univariate分析:r=0.185,P=0.026;multivariate分析:r=0.172,P=0.038)并且那唯一的位比率是为拉长的阴茎长度的一个重要预兆的因素(univariateanalysis:r=−;0.216,P=0.009;multivariate分析:r=−;0.201,P=0.024;拉长的阴茎length=−;9.201×;位比率+;20.577)。把证据基于这,我们建议位比率能预言成年阴茎尺寸并且出生前的睾丸激素的效果可以部分地在成年阴茎长度解释差别。
简介:象kinematics一样的形态学是在flapping飞行的性能的一个批评决定因素。在bio-flyers的气体动力学上理解结构的特点的效果,有在翼尖的1,2,和4表现象徘回一样正弦曲线kinematics的方面比率(AR)的三个矩形的翅膀基于雷纳兹数字5300试验性地被调查。沿着翅膀跨度的部分切割上的流动结构被比较。更强壮的K-H不稳定性与更高的方面比率在翅膀的前缘旋涡上被发现。旋涡爆炸仅仅出现在high-aspect-ratio翅膀的外部spanwise地点上。在high-aspect-ratio翅膀上爆炸的旋涡也许是为什么的原因之一bio-flyers通常有low-aspect-ratio翅膀。除了当旋涡爆炸发生时,定量分析在更高的方面比率翅膀上展出前缘旋涡(LEV)的更大的无尺寸的循环。沿着跨度的AR1和AR2的平均无尺寸的发行量几乎在50%跨度等于无尺寸的发行量。流动结构和发行量分析证明正弦曲线kinematics与在类似的研究使用的简化flappingkinematics相比压制LEV的故障。在在当前的Re范围,全面流动结构不对雷纳兹敏感的AR4表演的雷纳兹数字效果结果数。