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:Anall-solid-statesingle-frequency1064nmlaserwitha100μspulsewidth,500Hzrepetitionrateand700mJsinglepulseenergyisdesignedusingseedinjectionandathree-stagemasteroscillatorpoweramplifier(MOPA)construction.Usingthisasabasis,researchonlong-pulselaserfrequencydoublingiscarriedout.Bydesigningandoptimizingthelithiumtriborate(LBO)crystal,thetheoreticallycalculatedmaximumconversionefficiencyηmaxreaches68%atM2=1,whileηminis33%atM2=3.Generationof212mJpulsesofgreenlightwitharepetitionrateashighas500Hzisobtainedfromafundamentalenergyof700mJ.Theexperimentalconversionefficiencyreaches31%andthepowerstabilityisbetterthan±1%.
简介:Thestudyonthedecaypropertiesofnewisotopeslocatedfarfromthebetastabilitylineiscurrentthefocusofnuclearphysics.ForisotopesintheregionZ>82andN<126,-emissionprevailsasradioactivedecaymodeand-spectroscopyisthemostimportanttooltoobtaininformationonthenuclearstructure.IntheheavynucleiregionwithN=124and126isotones,anintruderstate(h9=2.f7=2)8+basedontheattractiveinteractionoff7=2protonsandf5=2neutronshasbeensignificantlyobserved,whichincreasesthebindingenergyofthisconfigurationwithincreasingprotonnumber.
简介:题目:区域降雨频率分析中的质量和数量不确定性分析目的:通过引进NUSAP方法量化区域降雨频率分析不确定性来源中质量方面的不确定性,并结合数量方面的不确定性,分析这些不确定性对降雨频率分析的影响,为水资源风险决策和水利工程设计等提供更好的指导。 创新点:总结区域降雨频率分析中的不确定性来源,并在区域频率分析中引进NUSAP方法用以量化其质量不确定性,针对区域频率分析提出Pedigree矩阵。 方法:1.选取区域频率分析中三个主要不确定性来源,即降雨测量不确定性、水文分区不确定性和分布线型的不确定性;2.提出针对区域频率分析的评价依据Pedigree矩阵,量化区域频率分析中的质量不确定性;3.将质量和数量两类不确定性结合在不确定性诊断图中,综合评估区域频率分析中的质量不确定和数量不确定性。 结论:NUSAP方法可以有效地量化区域降雨频率分析中的质量不确定性,并通过不确定性诊断图将质量不确定和数量不确定性很好地结合起来,为水资源风险决策和水利工程设计等提供了直观的方案。
简介:Weconductedalong-termmonitoringexperimentontheLutuanxiluBridgelocatedinChangpingDistrictofBeijing,employingourrecentlydevelopedreal-timebridgemonitoringsystembasedontheGuralpCMG-6TDbroadbandseismometer.Weidentifiedthemodalparameterswiththestochasticsubspaceidentification(SSI)algorithm,andcontinuouslymonitoredthetemporalvelocityvariationwithcodawaveinterferometry.Theresultsshowthat:(1)thehighlysensitiveGuralpCMG-6TDbroadbandseismometer,whichrecordsthethree-componentvibrationsignalwithinbroadfrequencyrange,iswellsuitedforlong-termbridgehealthmonitoring.(2)Withthecontinuousvibrationsignalfromambientexcitation,thestochasticsubspacealgorithmcanrobustlyidentifythelow-ordermodalparametersandthecodawaveinterferometrycanaccuratelymonitorthetinyvelocityvariation.(3)Theelasticmodulusofbridgematerialschangessignificantlyassociatedwithvaryingtemperature,leadingtodiurnalvelocityvariationwithamplitudeofapproximately1%.Thevelocityvariationshowsstrongnegativecorrelationwithtemperaturefluctuation.Meanwhile,themodalfrequenciesremainquitestable,suggestingthatthevelocityvariationmaybeamoresensitivequantitativedamageindex.(4)Whilethemodalfrequenciesreflecttheintegratedhealthstatusofthebridge,thevelocityvariationcanbeutilizedtomonitorthelocalelasticmodulus.Therefore,itiscrucialforbridgehealthmonitoringtocontinuouslymonitorthetwokeydamageindexesunderambientexcitation.