学科分类
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10 个结果
  • 简介:Inthispaper,someteststatisticsOfKolmogorovtypeandCramervonMisestypebasedonprojectionpursuittechniqueareproposedfortestingthesphericityproblemofahigh-dimensionaldistribution.Thelimitingdistributionsoftheteststatisticsarederivedunderthenullhypothesis.TheasymptoticpropertiesofBootstrapapproximationareinvestigatedandthetailbehaviorsofthestatisticsarestudied.

  • 标签: 椭圆 对称性 渐进线 统计学
  • 简介:GeoscienceinstructioninIndiaisfacingaseriouscrisis-instancesareknownofwell-establisheduniversitygeologydepartmentswithmorethanascoreofseniorteachershavingjustacoupleofM.Sc.students.Thisprofoundlackofdemandforgeosciencestudiesisadirectconsequenceofthepaucityofemploymentopportunitiesfortradition-ally-trainedgeosciencegraduateswhich

  • 标签: 地球科学 印度 地质学 研究
  • 简介:Themodulationinstabilityofquasi-plane-waveopticalbeamsisinvestigatedintheframeofgeneralizedSchrodingerequationwiththenonlineartermofageneralform.Generalexpressionsarederivedforthedispersionrelation,thecriticaltransversespatialfrequency,aswellastheinstabilitygrowthrate.Theanalysisgeneralizestheknownresultsreportedpreviously.Adetaileddiscussiononthemodulationinstabilityinbiasedcentrosymmetricphotorefractivemediaisalsogiven.

  • 标签: 不稳定性调制 宽光束 非线性介质 类平面波
  • 简介:大多数淡水鱼擅长转演习。一个模仿的鱼尾巴模型数字地详细被调查并且讨论。这研究处理在鱼尾巴鳍上施加在的不稳定的力量和时刻一起始斜着,击和随后的回来击打手势,并且设想流动领域和旋涡结构,鱼打手势以便探索典型拐弯处的流动控制机理。在相应于在它的C开始的鱼尾巴鳍的二张不同弯曲表格的动态后果被给的液体上推进讨论。Thetwo维的不稳定的不可压缩的海军司烧方程与一个developedpseudo压缩的可能性方法被解决在鱼尾巴鳍附近模仿流动。有实验的计算结果和比较显示那(1)钓鱼用过程展览的往来活动的中风,和每个阶段生产的冲动的时刻执行它的身体的一个转弯的运动它的特定的水动力学特征,(2)鱼采用尾巴尖端拐弯(单个拐弯和两倍拐弯)的二张表格完成C开始拐弯处演习,在他们的物理状况和自然环境的依赖,(3)鱼能由modulating控制它的转弯的运动一些关键运动学的参数。

  • 标签: 鱼尾模型 转向 不稳定力 流体场 涡旋结构
  • 简介:Thesubtropicalmixedbroad-leavedandconiferousforest,atypicalsuccessionalmonsoonforest,isoneofthemajorforestsinthesubtropicsofChina.Therefore,itisveryimportanttoestimatethefluxesofthegreenhousegasesfromtheforestsoilinordertoevaluatetheimpactofsubtropicalforestsonthegreenhousegasemissionsorabsorptions.Thisstudyinvestigatedthediurnalvariationsoffluxesofthreegreenhousegases(CO2,CH4,andN2O)fromamixedbroad-leavedandconiferousforestsoil.Astaticchamber-gaschromatographtechniquewasusedtomeasurethefluxesofthreegreenhousegases.Byusingtheimprovedgaschromatographysamplingsystem,thefluxeswereanalyzedwithasingleinjection.Inordertofindouttheeffectsoflitterandseedlingontheemissionsorabsorptionsofthesegreenhousegases,threetreatmentsweresetinthefleld:(1)baresoilsurface(litterwasremovedpreviously);(3)litter+soil;(3)seedling+litter+soil.TheexperimentalresultsdemonstratedthattheforestsoilwasasourceofCO2,N2OandaweaksinkofCH4.ThedailyfluxesofCO2,CH4,andN2Ofromthesoilsurfacewereintherangeof488.99~700.57,0.049~0.108and-0.025~-0.053mg/(m^2·h),respectively.CO2fromthelitterdecompositionaccountedforabout1/3ofthetotalCO2emissionfromthesoilsurface,whilethelitterandseedlinghadnosignificanteffectonthefluxesofCH4andN2O.ThefluxesofCO2andN2Omeasuredat9:00-11:00a.m.weresignificantlydifferentfromtheirdailyaverages.Therefore,cautionmustbetakeniftheCO2andN2Ofluxesmeasuredwithin9:00-11:00a.m.areusedforextrapolation.

  • 标签: 鼎湖山 温室气体 辐射 吸收 流量 日变化