简介:从上世纪70年代起,美国人民开始重视环保问题,美国政府制定的对空气、污水和废弃物进行处理的管制条例也第一次付诸实施.
简介:ThebasicschemeoftheorientationdetectionsystemusingL-shapereticleisintroduced.Thedimensionofthepatternsonthereticleofthesysteminpracticalapplicationsisdesignedandananalysisoftheprincipleofabstractingtheorientationinformationofthetargetandtheeffectsandformationmethodofself-adaptingtrackinggateispresented.TheresearchresultshowsthattheorientationdetectionsystemusingL-shapereticlehasagoodeffectonspace-filtering,thesignalsthattheorientationdetectionsystemsendsoutareeasytobeprocessedbycomputer,itsself-adaptingtrackinggatehasastronganti-interferenceability,andthewholesystem’ssearchingandtrackingperformancesarequitehigh.
简介:Thispaperpresentsthesimulationandmeasuredresultsofatriple-bandL-shapedmonopoleantennawithdefectedgroundplaneforapplicationsinwirelesslocalareanetworks(WLANs)andworldwideinteroperabilityformicrowaveaccess(WiMAX)bands.Thetriple-bandL-shapedmonopoleantennawithdefectedgroundplanewasfabricatedonaFR4substrate.Thelowerbandisassociatedwiththeshortedparasiticstripintheprotrudingstubofthegroundplane;themiddlebandisexpectedtobecontrolledbythelongerstripofL-shapedmonopoleinthefrontside,whilethehigherbandisassociatedwiththeshortstripofL-shapedmonopoleinthefrontside.Theproposedantennahasagoodagreementbetweenthemeasuredandthesimulationresults.Ithasa10dBreturnlosswiththebandwidthof250MHz(2270MHzto2520MHz)inthelowerband,600MHz(3320MHzto3,920MHz)inthemiddleband,and1110MHz(5030MHzto6140MHz)inthehigherband.TheproposedantennacoverstheISM(industrial,scientificandmedical),HIPERLAN(highperformanceradiolocalareanetwork),UNII(unlicensednationalinformationinfrastructure),andWiMAXbands.
简介:Themixedl1/H2optimizationproblemforMIMO(multipleinput-multipleoutput)discrete-timesystemsisconsidered.Thisproblemisformulatedasminimizingthel1-normofaclosed-looptransfermatrixwhilemaintainingtheH2-normofanotherclosed-looptransfermatrixatprescribedlevel.ThecontinuitypropertyoftheoptimalvalueinrespecttochangesintheH2-normconstraintisstudied.Theexistenceoftheoptimalsolutionsofmixedll/H2problemisproved.Becausethesolutionofthemixedl1/H2problemisbasedonthescaled-Qmethod,itavoidsthezerointerpolationdifficulties.Theconvergentupperandlowerboundscanbeobtainedbysolvingasequenceoffinitedimensionalnonlinearprogrammingforwhichmanyefficientnumericaloptimizationalgorithmsexist.
简介:本文采用负电源纯模拟电路方案对长波段掺铒光纤放大器(L-bandEDFA)的980nm泵浦激光器的驱动电路和温度控制电路进行了设计和调试,得到符合设计要求的结果.并以此为基础对我们自制的L-bandEDFA进行了实验测试,取得了令人满意的结果.