简介:如果你能够看懂时钟,你就可以知道一天的时间.但是谁也不知道,时间本身究竟是什么.时间是看不到、摸不着、听不见的,我们只能通过记录时间消逝的办法才知道时间的存在,虽然我们成功地测量了时间的分分秒秒,但时间仍然是宇宙间极其神秘的现象之一。
简介:<正>JinShanlingisonthewayofaspectacular7milehiketotheincredibleknife-edgepeaksatSimatai.Fromeachwatch-tower(67aresaidtogracethissection)itisliketheGreatWallforthefirsttime.ItisaswayingcablebridgecrossestoSimatai.Atoptoursreachedthroughsteep,narrowstepsaremillion-dollarvistasofanendlessdragon’stail.Here,thewall
简介:Alocalizedparametrictime-shearedGaboratomisderivedbyconvolvingalinearfrequencymodulatedfactor,modulatinginfrequencyandtranslatingintimetoadilatedGaussianfunction,whichisthegeneralizationofGaboratomandismoredelicateformatchingmostofthesignalsencounteredinpractice,especiallyforthosehavingfrequencydispersioncharacteristics.Thetime-frequencydistributionofthisatomconcentratesinitstimecenterandfrequencycenteralongenergycurve,withthecurvebeingobliquetoacertainextentalongthetimeaxis.Anovelparametricadaptivetime-frequencydistributionbasedonasetofthederivedatomsisthenproposedusingaadaptivesignalsubspacedecompositionmethodinfrequencydomain,whichisnon-negativetime-frequencyenergydistributionandfreeofcross-terminterferenceformulticomponentsignals.Theresultsofnumericalsimulationmanifesttheeffectivenessoftheapproachintime-frequencyrepresentationandsignalde-noisingprocessing.