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25 个结果
  • 简介:Neutralbeaminjectionisoneofthemainplasmaheatingmethodsinnuclearfusiondevices.InordertosupportthescientificstudyoftheExperimentalAdvancedSuperconductingTokamak(EAST),amegawatt-levelhighcurrentionsourceisdesignedandmanufacturedintheASIPP,andtheprogressandpreliminarytestresultswillbepresentedinthispaper.

  • 标签: 强流离子源 兆瓦级 超导托卡马克 核聚变装置 中性束注入 ASIPP
  • 简介:Radiointerference(RI),asanaftereffectofcoronadischarge,isanimportantresearchtopicinthefieldofelectromagneticcompatibility,whereexcitationfunctionisappliedbroadlytothepredictionofRIlevel.ThispaperpresentsthetheoryofexcitationfunctionmethodusedintheRIlevelprediction.Then,somepracticalproblemsrelatedtothismethodarediscussed.Thepropagationprocedureofcoronacurrentissolvedbythephase-modaltransformation,andtheimpedancematrixofmultitransmissionlinesiscalculatedbyadoublelogarithmicapproximatemodelofCarson'sGround-Returnimpedance.Atthesametime,inordertocalculatetheRIlevelwhentotallinecoronaisassumed,ananalyticalformulaisdeducedforintegraloperation.Basedontheabovesolutions,analgorithmispresentedandappliedtothepredictionofRIlevelofapracticaloverheadtransmissionline.Comparisonofpredictionandmeasurementresultsindicatesthatthealgorithmproposedinthispaperiseffectiveandfeasible.

  • 标签: 电晕放电 预测 激励 应用 架空输电线路
  • 简介:GroundlevelozonepollutionhasbecomeasignificantairpollutionprobleminBeijing.Becauseofthecomplexwayinwhichozoneisformed,itisdifficultforpolicymakerstoidentifyoptimalcontroloptionsonacost-effectivebasis.Thispaperidenti-fiesandassessesarangeofoptionsforaddressingthisproblem.WeapplytheAmbientLeastCostModelandcomparetheeco-nomiccostsofcontroloptions,thenrecommendthemosteffectivesequencetorealizepollutioncontrolatthelowestcost.ThestudyfindsthatinstallingofStageIIgasolinevaporrecoverysystematBeijing's1446gasolinestationswouldbethemostcost-effectiveoption.Overall,optionstoreduceozonepollutionbycuttingve-hicularemissionsaremuchmorecost-effectivethanoptionsto'cleanup'coal-firedpowerplants.

  • 标签: 成本效益 臭氧污染 控制方案 周边地区 北京 地面
  • 简介:A小说二水平花键方法为半线性的椭圆形的方程被建议,在二次水平重复与不同订单在一双层次花键空格之间被实现的地方。新二个水平方法是以p-adaptivity的一种方式的实现。一个粗糙的解决方案从在低顺序花键空格解决模型问题被获得,并且有更高的精确性的解决方案随后被产生,经由在高顺序花键空格的一步牛顿或monidifed牛顿重复。我们也导出最佳的错误评价为建议了二个水平计划。最后,说明数字结果证实我们的错误评价和进一步的研究话题被评价。

  • 标签: 半线性椭圆型方程 样条函数空间 最佳误差估计 椭圆型方程组 牛顿迭代 空间问题
  • 简介:ThispaperexaminesthelivelihoodchallengesexperiencedinRwanjabaLakeshoreCommunityduringtheperiodoflowwaterlevelinLakeVictoriabetween2004and2007andidentifiesthelivelihoodcopingstrategiesthatwereadoptedtoaddressthem.Atotalof55householdswererandomlysampledandthedatacollectionmethodsincludedhouseholdquestionnairesandparticipantobservations.ThedatawereanalyzedusingtheStatisticalPackageforSocialScience(SPSS)andtheresultspresentedwiththehelpofdescriptivestatistics.Thelivelihoodchallengesexperiencedduringthelowlakewaterlevelincludedfishshortage(34.5%),householdfoodscarcity(23.6%),sexforfish(18.2%),familybreakdown(12.7%),increasedtheft(7.2%)andaccidentsduetotheexposedrocksinthelake(3.6%).Thelivelihoodcopingstrategiesadoptedtoredressthechallengesincludedcausallabour(32.7%),maizeroasting(23.6%),sandmining(18.2%),sellingofsnacks(12.7%),sellinghouseholdproperty(9.1%)andresortingshopandmarketcredits(3.6%).Thepaperproposesanumberofrecommendationsforimprovingthelivelihoodofthecommunityrangingfrompolicyreformstothediversificationofactivities.

  • 标签: 维多利亚湖 水位降低 社区 湖岸 乌干达 家庭财产
  • 简介:Nonlinearmixedeffectsmodel(NLMEM)isbuiltontherelationshipofthefixedandrandomeffectsintheregressionfunction.TheNLMEMhasanobviouscomparativeadvantageinanalyzingthelongitudinaldata,repeatedmeasuresdataandmultileveldata.Two-levelNLMEMisusedtoanalyzethedominantheightforChinesefir(Cunninghamialanceolata).Theauthorsoutlinethetwo-levelNLMEMandintroducetheparametersestimationmethodofthemodel.BasedonfivecommonRichardandLogisticmodels,themixedmodelisbuilt.Themodelingdataareusedtocalculateandcomparewith19modelsderivedfromeachbasedmodel,and5optimalmixedmodelsarebuilt.Comparedthe5optimalmixedmodelswithtraditionalregressionmodels,itisshowedthatthetwo-levelNLMEMhasabetterfittingeffectthantheregressionmodel.

  • 标签: TWO-LEVEL nonlinear MIXED effects MODEL DOMINANT
  • 简介:Basedonamultilevellinearmixedmodelapproach,anindividualdiameterincrementmodelwasdevelopedforfirplantationtreesgrowinginJiangxiProvince.Thedatasetusedinthisstudycamefromlong-termpermanentresearchplots.Thedatabaseconsistsoftotalof82counties,365plots,5416treesand16248observations.Thepaperchosemixedeffectsmodelsinsteadofregressionanalysisapproachbecauseitallowsforpropertreatmentoferrortermsandcorrelationinarepeatedmeasuresanalysisframework.Themodelwasdefinedasamixedlinearmodelwithparameterrandomeffectofplot,areaorplotandareasimultaneous.Inadditiontheheteroscedasticityandcorrelationwastakenintoaccount.Mixedmodelcalibrationofdiameterincrementwascarriedoutwiththeindependentdatausingadifferentsampleofcomplementaryobservations.Theresultshowedthatthetotalstandbasalarea,thediameteroftargettrees,theratioofbasalareaoflargertreestotargettreediameter,andaltitudewerefoundtobesignificantpredictors.Boththefittingmodelandthecalibratedmodelmeanasubstantialimprovementcomparedwiththeclassicalapproachwidelyusedinforestmanagement.Aftertakingintoaccountreasonablevariancefunctionofheteroscedasticityandcorrelation,themodelshowsbetterofgoodnessoffitthanonlytakingintoaccountparameterrandomeffects.Thistypeofmodelingmethodologyshowsflexible,preciseandaccurate.

  • 标签: INDIVIDUAL diameter INCREMENT HETEROSCEDASTICITY correlation structure