简介：HistoricaldataregardingZhangHeng'sseismoscopeisnotsingularproof.Actually,thefourearliesthistoricaldocuments,i.e.,ContinuationofHistoriographyofHanDynasty,HistoriographyoftheLaterHan,BookoftheLaterHanandDingRecordallhaverelevantrecordsofitsstructure,size,principle,responsetoearthquakeandactualapplications.Thesefiveaspectsaresupportedbyarchaeologicalresearch,unearthedculturalrelics,historicalearthquakesandmodernseismologicalstudy.Thesehistoricalmaterialscontainagreatdealofspecificinformationaboutthisancientseismoscope.Inconclusion,theauthenticityandreliabilityofZhangHeng'sseismoscopeareverified.

简介：

简介：

简介：AtheoreticalinvestigationonthepH-inducedswitchingofmixedpolyelectrolytebrusheswasperformedbyusingamoleculartheory.TheresultsindicatethattheswitchingpropertiesofmixedpolyelectrolytebrushesaredependentonthepHvalues.AtlowpH,negativelychargedchainsadoptacompactconformationonthebottomofthebrushwhilepositivelychargedchainsarehighlystretchedawayfromthesurface.AthighpHvalues,theinversetransformationtakesplace.TheroleofpHdeterminingthepolymerchainsconformationandchargebehaviorofmixedpolyelectrolytebrusheswasanalyzed.Itisfoundthatthereexistsamechanismforreducingstrongelectrostaticrepulsions:stretchingofthechains.TheH+andOH-unitsplayamoreimportantroleascounterionsofthechargedpolymersdo.ThecollapseofthepolyelectrolytechainsfordifferentpHvaluescouldbeattributedtothescreeningoftheelectrostaticinteractionsandthecounterion-mediatedattractiveinteractionalongthechains.

简介：

简介：Numericalsimulationsof10kWand110kWinductivelycoupledplasma(ICP)windtunnelswerecarriedouttostudyphysicalpropertiesoftheflowinsidetheICPtorchandvacuumchamberwithairastheworkinggas.Two-dimensionalcompressibleaxisymmetricNavierStokes(N-S)equationsthattookintoaccount11speciesand49chemicalreactionsofair,weresolved.Aheatsourcemodelwasusedtodescribetheheatingphenomenoninsteadofsolvingtheelectromagneticequations.Inthevacuumchamber,afour-temperaturemodelwascoupledwithN-Sequations.Numericalresultsforthe10kWICPwindtunnelarepresentedanddiscussedindetailasarepresentativecase.Itwasfoundthattheplasmaflowinthevacuumchambertendedtobeinlocalthermochemicalequilibrium.Tostudytheinfluenceofoperationconditionsontheflowfield,simulationswerecarriedoutfordifferentchamberpressuresand/orinputpowers.ThecomputationalresultsfortheabovetwoICPwindtunnelswerecomparedwithcorrespondingexperimentaldata.Thecomputationalandexperimentalresultsagreewell,thereforetheflowfieldsofICPwindtunnelscanbeclearlyunderstood.

简介：作为在许多设计应用程序的一个基本问题，到骚乱的从laminar的转变在计算液体动力学(CFD)仍然是一个困难的问题。一过渡流动在的数字研究二维被雷纳兹进行在这份报纸的平均数字模拟(RANS)。骚乱模型戏在复杂流动模拟的一个重要角色，和四个先进骚乱模型被评估。摩擦抵抗系数的数字答案与在过渡地区的测量那个相比，它显示有修正的那个威尔科克斯(2006)k-模型是最好的候选人。平均无尺寸的速度介绍的streamwise的无尺寸的速度表演的数字、分析的解决方案的比较在过渡区域很快改正形状。而且，象骚乱动能，旋涡粘性，和雷纳兹应力那样的骚乱数量也被学习，它是有用的学习转变行为。

简介：由对改进隔离表演的需要激发了，许多研究研究与非线性的特征在隔离乾上被执行了。基于他们的阶段肖像的形状，如此的设备能作为也被设置单稳态或双稳态的隔离乾。这篇论文集中于在一样的刺激下面调查这二个班的相对表演。力量能递送被用来测量隔离表演，它以播送力量的比率的RMS被定义到刺激力量。当系统受到泛音刺激时，在隔离的力量能递送的最大的减小用伪变化，这被发现--零僵硬被完成。当系统受到随机的刺激时，它有伪的一样的效果--零僵硬。进一步，最佳抑制能与僵硬被改变并且有最小的价值。

简介：ThenaturalconvectiveheattransferperformanceofanaluminumhexagonalhoneycombactingasanovelheatsinkforLEDcoolingisexperimentallyinvestigated.Theconceptofaddinganadiabaticsquarechimneyextensionforheattransferenhancementisproposed,andtheeffectsofchimneyshape,height,anddiameterarequantified.TheaverageNuavofaheatedhoneycombwithstraightchimneyissignificantlyhigherthanthatwithoutchimney,andtheenhancementincreaseswithincreasingchimneyheight.Atagivenchimneyheight,honeycombswithdivergentchimneysperformbetterthanthosewithconvergentones.Forafixeddivergentangle,theNuavnumberincreasesmonotonicallywithincreasingchimneyheight.Incontrast,withtheconvergentanglefixed,thereexistsanoptimalchimneyheighttoachievemaximumheattransfer.

简介：

简介：上演注射者展出了大潜力完成低排出物并且正在成为许多民用的飞机的更好的选择。而且，它正在答应在军事引擎采用这个注射者图案，它要求大多数空气进入的燃烧通过到还原剂烟排放的注射者的燃烧室。然而，瘦上演注射者在低负担操作对燃烧不稳定性和扑灭敏感，因此为拓宽它的稳定的操作范围的技术为它在真实引擎的申请是关键的。

简介：有电磁的领域的不同安排的一个MHD生成器将带在三个模式工作的生成器。quasi-one-dimensional近似被用于MHD发电机的模型分析操作模式的内部机制。为有一个一致经常的磁场的MHD发电机，特定的批评电场E<潜水艇class=“a-plus-plus”>cr被要求速度超声的入口流动进亚声的出口流动。否则，发电机比E与一个更大的电场在一个稳定的模式工作稳定的超声的流动在出口在被提供的cr，或发电机比E与一个更小的电场在一个窒息的模式工作超声的入口流动在隧道在被窒息的cr。在不同操作模式的详细流动地特征被讨论，表明有电磁的地的操作模式的关系。

简介：Thispaperaddressestheproblemoftherenormalizationgroupkturbulencemodelingofavegetatedmulti-stagecompoundchannel.ResultsfromMicroacousticDopplervelocimeter(ADV)testsareusedwithtimeandspatialaveraging(doubleaveragingmethod)intheanalysisoftheflowfieldandthecharacterization.Comparisonsofthemeanvelocity,theReynoldsstress,andtheturbulentenergydistributionshowthevalidityofthecomputationalmethod.Themeanvelocityprofileseesanobviousdecelerationintheterracesbecauseofvegetation.Secondaryflowexistsmainlyatthejunctionofthemainchannelandthevegetationregiononthefirstterrace.Thebedshearstressinthemainchannelismuchgreaterthanthatintheterraces.Thedifferenceofthebedshearstressbetweentwoterracesisinsignificant,andthepresenceofvegetationcaneffectivelyreducethebedshearstress.

简介：Asanimportantmulti-functionalmaterialappliedinsurfaceacousticwavedevices,opticalcommunications,laserandoptoelectronicsduetoitsgoodphotoelectricandpiezoelectricproperties,lithiumtantalate(LiTaO3)hasdrawnextensiveinterests[1].NumerousphysicalpropertiesofLiTaO3,suchasacoustical,electronicstructures,opticalpropertiesandeffectivemass,thermodynamicproperties,havebeenreportedinseveralpapers.Pointdefectswillaffecttheelectronicstructurewhichshouldberesponsibleformanyphysicalproperties,especiallyopticalproperties.

简介：Themonitoredresonantbehavioroffatiguespecimensofmetastableausteniticstainlesssteel(AISI304)iscorrelatedwithitsdamageaccumulationintheveryhighcyclefatigue(VHCF)regime.Theresonantbehaviorisstudiedexperimentallyandshowsadistincttransientcharacteristic.MicroscopicexaminationsindicatethatduringVHCFalocalizedplasticdeformationinshearbandsarisesonthespecimensurface.Hence,thisworkfocusesontheeffectofdamageaccumulationinshearbandsontheresonantbehaviorofAISI304intheVHCFregime.Amicrostructuralsimulationmodelisproposedthattakesintoaccountspecificmechanismsinshearbandsprovenbyexperimentalresults.Thesimulationmodelissolvednumericallyusingthetwo-dimensionalboundaryelementmethodandtheresonantbehaviorischaracterizedbyevaluatingtheforce-displacementhysteresisloop.Simulationofshearbandsagreeswellwithmicroscopicexaminationsandplasticdeformationinshearbandsinfluencesthetransientcharacteristicoftheresonantbehavior.

简介：

简介：Theflowbetweentwocoaxialconicalcylindersisnumericallystudiedfortwodifferentconfigurations,withtheinnerconerotatingandtheouteroneatrest.Itisfoundthat,inoneconfiguration,atleastatasmallReynoldsnumber(Re),thepressureisadecreasingfunctionofzwhileintheotherconfiguration,itisanincreasingfunctionofz.Inthefirstconfiguration,thepressurecurvesfordifferentRehaveintersections,whileinthesecondconfigurationtheydonot.ThegapbetweentwoconicalcylindersisfilledwithsixpairsofTaylorvorticesataboutthesameReynoldsnumberandineachpairofvorticesinthefirstconfiguration,theuppervortexislargerthanthebottomonewhileinthesecondconfiguration,thebottomvortexislargerthantheupperone.

简介：<正>ADunaliellastrainwasisolatedfromYunchengSaltLake,Shanxi,China(111.05°E,35.03°N).MorphologicalcharacteristicsandmoleculardatawereusedtoevaluatetherelationshipofthisalgalstraintootherDunaliella

简介：ThehotductilityofFe-36NiinvaralloywithdifferentadditionsoftheelementceriumwasinvestigatedusingaGleeble-3800thermal-mechanicalsimulatoroverthetemperaturerange850-1050℃,andtheimprovementmechanismofthehotductilitywasanalyzedusingacombinationofSEM,EDS,andOM.TheresultsindicatedthatFe-36Niinvaralloyexhibitedpoorhotductilitybelow1050℃,whichwasmainlyattributedtoweakgrainboundariesandtheactionofgrainboundarysliding.However,thealloyswithceriumcontentsof0.016%and0.024%bothdemonstratedsubstantialimprovementinthehotductilityovertheentiretestingtemperaturerange.Theobservedimprovementofthehotductilityofthealloywith0.016%ceriumat950℃andthealloywith0.024%ceriumat900℃wasassociatedmainlywiththegrainboundarystrengtheningandtherestrictionofthegrainboundaryslidingbecausetheadditionofceriumreducedthesegregationofsulfuratgrainboundariesandrefinedthegrainstructure.Theoccurrenceandaccelerationofdynamicrecrystallizationwerefoundtoberesponsibleforthehighhotductilityofthealloywith0.016%ceriumat1000℃andthealloywith0.024%ceriumat950-1000℃asaresultoftherefinementofthegrainstructurebyadditionofcerium.

简介：Throughthesamplesurveyofprimaryandjuniorhighschoolstudentsandteachersonstudents＇physiquefromvariousprovincesandcitiesinChina,theresulthasshownthedeclineofstudents＇physique.Therearemanyreasons.Forstudents,thereasonsaretheheavyacademicburden;lackofinterest,time,andknowledgeinphysicalexercise;andthatthehabitofexercisewasnotdeveloped.Forfamily,familyeducationremainsfocusingmoreonintellectualthanphysical,nutritionthanexercise,andignoringthepositionandroleofsportsinthefamily.Forschool,thereasonsarethelackofsupportforphysicaleducation,thelimitedsportsactivities,andthetediousacticitytype.Forcommunity,thesportsfacilitiesandfieldsareinsufficient,andthereexistsanunevendistributionbetweenruralandurban.Bymeansofimplementinglawsandregulationsofphysicaleducation,strengtheningschoolsportsinfrastructure,enrichingteachers＇professionalknowledgeofphysicaleducation,stimulatingstudents＇interestinphysicalexercise,andeliminatingtheblindunderstandingofphysicalhealthbyparents,wecanpromotestudents＇physique.