简介:以杭州曲院风荷景点为研究对象,以历史文献为线索,结合山水画、版画、照片、测绘图等图像资料,梳理其景观格局变迁历程,分析演变中景物间的联系,并对各时期园林发展情况进行总结。将其发展历程划分为南宋麯院时期、元代至明代衰落时期、清代更址重建时期及中华人民共和国成立至今的公园化时期。认为清康熙年间曲院的迁址与更名是景点发展的重要转折点,这一举动既使古老的景名得以延续,又使景点有了新的内涵和发展空间。园林建筑与环境的营造围绕"曲"这一主题展开,代表人工的"曲院"与代表自然的"风荷"体现了该景点人工建筑与自然景物并重的审美主旨。通过分析整理历史图像资料对于今人了解古代园林变迁有重要帮助。
简介:Wedemonstrateanall-fiberhigh-powerYb-doped1018nmfiberlaserwithaGaussian-shapedoutputbeamprofilebasedonamismatchedstructure,whichconsistsofapairofsingle-modefiberBragggratingsandasectionoffew-modedouble-claddinggainfiber.Theoutputpowerisupto107.5Wwithanoptical-to-opticalefficiencyof63%,andthe3dBbandis0.26nmatthispowerlevel.Suchastructureofsingle-mode–few-mode–single-modefiberoscillatorcanbeusedtogeneratehigh-powernarrow-linewidthlasingwithexcellentbeamqualityinotherspectralranges.
简介:Wereportonthehigh-poweramplificationofa1064nmlinearlypolarizedlaserinanall-fiberpolarizationmaintainedmasteroscillatorpoweramplifier,whichcanoperateatanoutputpowerlevelof1.3kW.Thebeamquality(M~2)wasmeasuredtobe<1.2atfullpoweroperation.Thepolarizationextinctionrateofthefiberamplifierwasmeasuredtobeabove94%beforemodeinstabilities(MIs)setin,whichreducedtoabout90%aftertheonsetofMI.ThepowerscalingcapabilityofstrategiesforsuppressingMIisanalyzedbasedonasemianalyticalmodel,thetheoreticalresultsofwhichagreewiththeexperimentalresults.ItshowsthatmitigatingMIbycoilingthegainfiberisaneffectiveandpracticalmethodinstandarddouble-claddinglargemodeareafiber,and,bytightcoilingofthegainfibertotheradiusof5.5cm,theMIthresholdcanbeincreasedtothreetimeshigherthanthatwithoutcoilingorloosecoiling.Experimentalstudieshavebeencarriedouttoverifytheidea,whichhasprovedthatMIwassuppressedsuccessfullyintheamplifierbypropercoiling.
简介:深圳市新元铁材料有限公司专业服务模具企业,提供一站式模具钢材采购解决方案!展品一:阿赛洛SP300化学成分-重量百分比舆型值(钢板厚度100mm)SUPERPLAST300(SP300)是一种塑料模具钢,预硬到300HB。SUPERPLAST300专门设计用于满足当前塑料模工业的需求。它的原创化学成分确保了特定的性能,可有效代替常规P20和1.2738等钢种:极高的加工性:均匀的优化硬化能力(最厚到910mm);优异的焊补性能;高的热导率。此外,对于模具制造商和模具用户而言,SP300也具有显著的优势,可以节省模具制造成本和模具使用成本。
简介:运用G′/G展开法研究了一类推广的Burgers方程,讨论了推广的Burgers方程的解的存在性及其求解过程,得到了推广的Burgers方程所有可能情形下的G′/G解。
简介:Thispaperisdevotedtotheanalysisandcomparisonofeco-civilizationconstructionmodesinChinaandmajordevelopedwesterncountries,whichmainlyfocusesonthetypicaladvancedrelatedecocivilizationconstructionmodesindifferentcountries,citiesorcounties.Finally,itmakesacomparativeanalysisathomeandabroad,drawstheconclusionandputsforwardsomemaincountermeasuresandsuggestionsforChina’seco-civilizationconstructiononthebasisoftheexistingresearch.
简介:WestudyspectroscopicsignaturesofamonochromaticbosonmodeinteractingwithaT-shapedoublequantumdotcoupledbetweenthemetallicandsuperconductingleads.Focusingonaweakinterdotcoupling,wefindthattheproximityeffecttogetherwiththebosonicmodeareresponsiblefortheseriesofFano-typeresonancesappearingsimultaneouslyatnegativeandpositiveenergies.WeinvestigatetheseinterferometricfeaturesanddiscusstheirinfluenceonthesubgapAndreevconductancetakingintoaccountthecorrelationeffectsdrivenbytheCoulombrepulsion.
简介:Propagationpropertiesofhigh-powerfiberlaserwithhigh-order-mode(HOM)contentarestudiednumericallyforthefirsttimetothebestofourknowledge.TheeffectofHOMonthepropagationpropertyisevaluatedbythepowerinthebucket(PIB)metric.ItisshownthatPIBismainlydependentonHOMcontentratherthantherelativephasebetweenthefundamentalmodeandHOM.ThePIBinvacuumismorethan80%whenthepowerfractionoftheHOMiscontrolledtobelessthan50%at5km.Therelativephasehasanimpactonthepeakintensitypositionandconcentrationofthefar-fieldintensitydistribution.Ifanadaptiveopticssystemisusedtocorrectthepeakintensitydeviation,theresultsindicatethatthereexistsamaximalvalueofPIBasrelativephaseincreases.Sucheffectisweakenedwhenpropagatinginturbulence.ComparedtothelaserbeamswithoutHOM,laserbeamswithHOMcontentarelessinfluencedbytheturbulenceandcanreduceaverageintensityfluctuation.Theresultsmaybeusefulinthedesignofahigh-powerfiberlasersystem.
简介:Coremodecutoffisausefulconceptnotonlyforataperedsingle-corefiber(SCF)butalsoforataperedmulticorefiber(MCF)torealizecladdingmodetransmission.Inthispaper,cut-offconditionsofeithercoremodefortaperedSCFsorsupermodesforMCFsaretheoreticallyinvestigated.RigorousanalyticalformulasarederivedforthemodesofSCFbyathree-layerwaveguidemodel,andanapproximationformulaofthecut-offconditionisgivenfortheLP01mode.ThesupermodesofMCFsareanalyzedbythecouplingmodetheory,andthecut-offconditioniscalculatedbyanumericalmethod.Simulationresultsshowthatthein-phasesupermodeofMCFshasasimilarcut-offconditionwiththatofSCF.Basedonthisproperty,aconvenientapproximateformulaisgiventoestimatethecut-offconditionofthein-phasesupermodefortaperedMCFs.
简介:Nowadayslow-carbondevelopmenthasbecomeahotissueofthewholeworld.Thisarticlefirstintroducesthebackgroundoflow-carboneconomy,andthenexplainstheimportanceofretailingcompaniesinsocialeconomyandthereasonswhytheyshouldoperateinlow-carbonmode.Morespecifically,low-carbonoperationcannotonlyimprovethecompetitivenessofaretailingcompanybyreducingoperationcostandformattinggoodcorporateimage,butalsobenefitthewholesocietybyreducingenvironmentpollutionandpromotinglow-carbonconsumptionandproduction.Onlybyadoptinglow-carbonoperationpatterncanretailingcompaniesconfrontthefierceinternationalcompetition.Toillustratetheabovepointofview,severalcasesoffamouswesternretailingcompanieswillbeanalyzedinthisessay.Tesco,Wal-MartandCarrefourarealltypicalexamplesinlow-carbonoperationbecausetheyallhavegreatgreenandsustainabilityinitiatives.Basedontheadvancedexperiencesoftheabove-mentionedcompanies,thisessaydiscussesthelow-carbonoperationways,puttingforwardsomevaluablesuggestionsonthisproblem.Fromatechnicalperspective,retailingcompaniesshouldadoptadvancedtechnologiesrelatingtolow-carbonoperation.Ontheotherhand,managementlevelofretailingcompaniesshouldbeenhancedtoensuretheapplicationeffectoflow-carbontechnologies.Retailingcompaniesshouldimprovetheabilityofinternalmanagementtoexcavatetheinternalpotentialandbuildgreensupplychaintocorporatewithstrategicpartners.Finally,thisarticlegivestheconclusionofthewholeanalysis.
简介:这份报纸与滑动模式控制进L1的集成论述一个适应控制计划适应控制建筑学,它提供好追踪表演以及坚韧性againstmatched无常。Slidingmode控制在L1被用作一条适应法律适应控制建筑学,它被看作在估计的状态和真实状态之间的错误动力学的虚拟控制。当维持控制精确性时,在控制法律设计的低通行证的过滤机制在适应法律阻止一个不连续的信号出现在实际控制信号。由把滑动模式控制用作错误动力学的虚拟控制并且介绍低通行证的过滤控制信号,啁啾的效果被消除。在靠近环的适应系统和靠近环的参考书系统之间的性能界限在这份报纸被描绘。数字模拟被提供表明介绍适应控制计划的表演。