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108 个结果
  • 简介:Withinthescopeofthisstudy,itisaimedtocontributetotheeffortsforformingadatabaseincludingthenaturalradiationlevelsthroughoutthecountryanddevelopingafoundationforradiationsafety.KarasuportionoftheEuphratesvalleywithintheprovincialborderofErzincanwaschosenfortheinvestigationandnaturalradiationlevelsweredetectedbyanalyzingthesamplestakenintermsofradioactivity,naturalenvironment’sradiationstreams.ThroughouttheregionofKarasu,29differentsamplesfromthewaterand17fromthesoilweretakenandtheirtotalalpha,betaactivitiesweredetected.Totakesamplesfromthewaterandthentheyweremeasuredbylowbackgroundcounter(BertholdbrandLB77010-channelcounter).Totalalphaandbetaanalysesweremadeaccordingtothestandardmethods.Averagevaluesofalphaandbetaconcentrationsofsamplesweremeasuredas0.0421Bq/Land1.806Bq/L,respectively.ForthesoilsamplesHPGegammaspectrometersystemwasusedandradioisotopeactivityconcentrationswerefoundwithintheintervalsof2.7-27.8Bq/kgfor226Ra;3.2-39.4Bq/kgfor232Th;98-714Bq/kgfor40K;<0.4-57.8Bq/kgfor137Cs,respectively.Differentradioisotopesweredetectedinsomeofthesamplestakenfromstreamingbedsjoiningriverwater.

  • 标签: Natural radiation Erzincan Karasu River VALLEY
  • 简介:Theoreticalmodelsofstellarevolutionpredictnegligiblequantitiesof6Li,9Be,and11Binthehydrogenburningphasesofastar’sevolution[1].TheprimordialBig-Bangnucleosynthesis(BBN)modelmightbemoregenerousinitsproductionoftheseelements[2].Theradiative-capturecrosssectionforprotoncaptureon11Bleadingto12CissmallatastrophysicallyinterestingenergiesbecauseofthelargeCoulombbarrier.

  • 标签: FACTORS LOW ENERGIES
  • 简介:PE3340芯片是Peregrine公司研制的一款低噪声、高性能整数分频锁相环,工作频率可高达3GHz,用20引脚TSSOP封装形式,芯片约6.5mm×6.4mm。PE3340内含一个双模前置分频器、R和M计数器以及鉴相器,可通过串行接口对芯片进行编程。遥测发射机设计是用Xilinx公司的CPLD芯片XC9536对PLL芯片PE3340进行预置数据编程。发射机设计用准两点注入式锁相调频技术,包括PE3340、XC9536、温补晶振(TCXO)、有源积分滤波器电路(LF)、VCO、缓冲放大器(Buffer)和S波段功放(PA)等电路模块。发射机电路原理框图如图1所示(虚线框内为PE3340)。

  • 标签: PE3340芯片 S波段 遥测发射机 结构设计 整数分频锁相环
  • 简介:SISAK是国内外目前应用最广泛的短寿命同位素快化分离技术之一,在裂变产物、超重元素、远离β稳定线的非稳核研究方面有着广泛的应用。SISAK技术最新的发展主要集中在配套设备和计算机控制上。我们研制了一套以S7-200PLC为核心的SISAK自动控制系统,其组成和控制方案简单可靠,已在冷实验中取得了很好的效果。

  • 标签: SISAK 短寿命核素分离 PLC 自动控制
  • 简介:我们理论上由认为Rashba是纺纱轨道在一个极极的半导体的接口附近学习极化子的扎根的州的精力(那么)结合theLee-Low-Pines中间的联合方法。我们的数字结果证明在异种结构从倒置不对称现象发源的RashbaSOinteraction切开极化子的扎根的州的精力。到总数的SOinteraction的比率的真实密度和向量依赖扎根了的电子州的精力或另外的精力作文是明显的。一个人能看到甚至没有任何外部磁场,扎根的州的精力能被RashbaSOinteraction切开,并且这切开不是一个单身者但是复杂的。自从礼品声子,其精力把否定贡献给极化子的家,极化子的切开纺纱的状态比电子的家更稳定。

  • 标签: 不对称异质结构 三角势能逼近 Rashba自旋轨道交互 数字结果
  • 简介:一个广泛地集成的40G-ROF和10-Gb/sWDM-PON多服务存取系统被建议并且试验性地示威了。这个计划由同时播送无线的独立2.5-Gb/s和10-Gb/s电线信号的40G-ROF和10-Gb/sWDM-PON的一个综合系统组成。在基础车站,它采用调整在DPSK下游的信号上策划在上游的OOK信号,它被remodulating完成,到减少基础车站的费用。传播实验在25-km-long单身者模式纤维(SMF-28)上被执行。下游的PON和ROF的敏感表明的结果表演是[?]14.5dBm并且[?]21.5dBm,分别地并且在上游的信号的敏感是[?]25.3dBm。[从作者抽象]

  • 标签: 无源光网络 波分复用 射速 Gb 接入网络 网络系统
  • 简介:AnovelSr2CuInO3Soxysulfidep-typesemiconductorphotocatalysthasbeenpreparedbysolidstatereactionmethodanditexhibitsintriguingvisiblelightabsorptionpropertieswithabandgapof2.3eV.Thep-typesemiconductorcharacterofthesynthesizedSr2CuInO3SwasconfirmedbyHallefficientmeasurementandMott-Schottkyplotanalysis.First-principlesdensityfunctionaltheorycalculations(DFT)andelectrochemicalmeasurementswereperformedtoelucidatetheelectronicstructureandtheenergybandlocations.Itwasfoundthattheas-synthesizedSr2CuInO3Sphotocatalysthasappreciateconductionandvalencebandpositionsforhydrogenandoxygenevolution,respectively.Photocatalytichydrogenproductionexperimentsunderavisiblelightirradiation(λ>420nm)werecarriedoutbyloadingdifferentmetalandmetal-likecocatalystsonSr2CuInO3SandRhwasfoundtobethebestoneamongthetestedones.

  • 标签: 半导体光催化剂 可见光照射 Mott-Schottky图 P型 制氢 密度泛函理论
  • 简介:MeisymmetryandMeiconservedquantityforanon-holonomicsystemofnon-Chetaev'stypewithunilateralconstraintsintheNielsenstylearestudied.Thedifferentialequationsofmotionforthesystemaboveareestablished.ThedefinitionandthecriteriaofMeisymmetry,conditions,andexpressionsofMeiconservedquantitydeduceddirectlyfromtheMeisymmetryaregiven.Anexampleisgiventoillustratetheapplicationoftheresults.

  • 标签: 非完整系统 非Chetaev型 守恒量 尼尔森 风格 对称美
  • 简介:Thedevelopment,theunderlyingtechnologyandthecurrentstatusofthefullydiode-pumpedsolid-statelasersystemPOLARISisreviewed.Currently,thePOLARISsystemdelivers4Jenergy,144fslonglaserpulseswithanultra-hightemporalcontrastof5×1012fortheASE,whichisachievedusingaso-calleddoublechirped-pulseamplificationschemeandcross-polarizedwavegenerationpulsecleaning.Bytightlyfocusing,thepeakintensityexceeds3.5×1020Wcm-2.TheseparameterspredestinePOLARISasascientifictoolwellsuitedforsophisticatedexperiments,asexemplifiedbypresentingmeasurementsofacceleratedprotonenergies.Recently,anadditionalamplifierhasbeenaddedtothelaserchain.Intheramp-upphase,pulsesfromthisamplifierarenotyetcompressedandhavenotyetreachedtheanticipatedenergy.Nevertheless,anoutputenergyof16.6Jhasbeenachievedsofar.

  • 标签: design high power LASER LASER amplifiers
  • 简介:Althoughmanyliteratureshavebeenfocusedontheunderneathflowandlossmechanism,veryfewexperimentsandsimulationshavebeendoneundertheengines'representativeworkingconditionsorconsideringtherealcavitystructureasawhole.Thispaperaimsatrealizingthegoalofdesignofefficientturbineandscrutinizingthevelocitydistributioninthevicinityoftherimseal.Withtheaidofnumericalmethod,anumericalmodeldescribingtheflowpatternbothinthepurgeflowspotandwithinthemainstreamflowpathisestablished,fluidmigrationanditsaccompaniedflowmechanismwithintherealisticcavitystructure(withrimsealstructureandconsideringmainstream&secondaryairflow'sinteraction)isusedtoevaluateboththeflowpatternandtheunderneathflowmechanismwithintheinwardrotatingcavity.Meanwhile,theunderneathflowandlossmechanismarealsostudiedinthecurrentpaper.Thecomputationalresultsshowthatthesealingairflow'singestionandejectionarehighlyinterwoundwitheachotherinbothupstreamanddownstreamflowoftherimseal.Boththedownstreamblades'potentialeffectsaswellastheupstreamblades'waketrajectorycanbringabouttheingestionofthehotgasflowwithinthecavity,abruptincreaseofthestaticpressureisbelievedtobethemainreason.Also,theresultsindicatethatsealingairflowejectedthroughtherearcavitywillcauseunexpectedlossneartheoutletsectionofthebladesinthedownstreamoftheHProtorpassages.

  • 标签: 二次密封 空气流动 低压涡轮 Flow 端壁 轮毂
  • 简介:Boundarylayerseparationandreattachmentisoftenanunavoidablefeatureoflowpressure(LP)turbine,oneofthemaincausesofthisphenomenonisthehighaltitudelowReynoldsnumberexperiencedbythemodernLPturbinestageinaero-engine.Althoughanexcellentturbineairfoildesigncanavoidflowseparationoncertainextent,butwithinflightenvelope,LPturbine'scharacteristicReynoldsnumbermayvariedgreatly,soitwillbestillundertheriskofthepresenceofseparationbubble.Inthistwopartspaperanewconceptofslotted-bladewasraisedtotestifythegainofthebladeslotting.AhighaerodynamicloadingLPturbinebladeIET-LPTAwasunderinvestigatedwithdifferentReynoldsnumber.ComputationalresultsrevealthatthebladeslottingcouldbeawayofchoicetosuppressseparationbubbleandreduceprofilelossundertheconditionoflowReynoldsnumber,althoughitspositionandgeometryneedtobefurtherinvestigated.

  • 标签: 低压涡轮 低雷诺数 计算结果 开槽 叶片表面 高负荷
  • 简介:TheZ-backlighterlaserfacilityprimarilyconsistsoftwohighenergy,high-powerlasersystems.Z-Beamletlaser(ZBL)(Ramboetal.,Appl.Opt.44,2421(2005))isamulti-kJ-class,nanosecondlaseroperatingat1054nmwhichisfrequencydoubledto527nminordertoprovidex-raybacklightingofhighenergydensityeventsontheZ-machine.Z-Petawatt(ZPW)(Schwarzetal.,J.Phys.:Conf.Ser.112,032020(2008))isapetawatt-classsystemoperatingat1054nmdeliveringupto500Jin500fsforbacklightingandvariousshort-pulselaserexperiments(seealsoFigure10forafacilityoverview).Withthedevelopmentofthemagnetizedlinerinertialfusion(MagLIF)conceptontheZ-machine,theprimarybacklightingmissionsofZBLandZPWhavebeenadjustedaccordingly.Asaresult,wehavefocusedourrecenteffortsonincreasingtheoutputenergyofZBLfrom2to4kJat527nmbymodifyingthefiberfrontendtonowincludeextrabandwidth(forstimulatedBrillouinscatteringsuppression).TheMagLIFconceptrequiresawell-defined/behavedbeamforinteractionwiththepressurizedfuel.HencewehavemadegreateffortstoimplementanadaptiveopticssystemonZBLandhaveexploredtheuseofphaseplates.WearealsoexploringconceptstouseZPWasabacklighterforZBLdrivenMagLIFexperiments.Alternatively,ZPWcouldbeusedasanadditionalfusionfuelpre-heaterorasatemporallyflexiblehighenergypre-pulse.AlloftheseconceptsrequiretheabilitytooperatetheZPWinananosecondlong-pulsemode,inwhichthebeamcanco-propagatewithZBL.Someoftheproposedmodificationsarecompleteandmostofthemarewellontheirway.

  • 标签:
  • 简介:Basedonloadseparationtheory,theloadseparationparameterSpbmethodisaneffectiveapproachforestimatingtheJ-resistancecurvefromrecordsofloadversusdisplacementdirectly,usingonesharpcrackedspecimenandanadditionalreferencebluntcrackedspecimen.However,theeffectofthereferencebluntcrackedspecimenonJ-resistancedeterminationwasnotexplicitlyconsideredinpastwork.Inthispaper,amodifiedloadseparationparameterSpbmethodwasdevelopedtoeliminatethiseffect,andthenauniqueestimationofinstantaneouscracklengthforonesharpcrackedspecimencouldbeobtained.Furthermore,aforcedbluntingcalibrationmethodwasalsoadoptedtodeterminetheinstantaneouscracklengthintheloadinseparableregion,referringtoanormalizationmethod.ExperimentsonsteamturbinerotatorsteelCr2Ni2MoVwerecarriedouttoestimateJ-resistancecurvesusinganunloadingcompliancemethod.Byremovingunloadandreloaddatafromload-displacementrecords,theJ-resistancecurveforthesamesharpcrackedspecimenwasestimatedusingthemodifiedseparationparameterSpbmethod.TheresultsindicatethatthemodifiedSpbmethodcompletelyeliminatestheeffectofthereferencebluntcrackedspecimenontheinstantaneouscracklengthdeterminationofthesharpcrackedspecimen.However,differentJ-resistancecurvesinasmallrangeofcrackextensionarepresentwhendifferentbluntingcoefficientsareusedinthebluntinglineequation.TheJ-resistancecurveobtainedfromthemodifiedSpbmethodagreeswellwiththatobtainedfromthecompliancemethod.

  • 标签: 汽轮机转子钢 阻力曲线 修改 估计 卸载柔度法 分离参数法