简介:建立了花生中10种农药残留的快速分析方法。样品用乙腈水均质提取,盐析分配,提取液经Envi-18和LC-NH2复合固相萃取小柱净化后供超高效液相色谱-串联质谱仪(UPLC-MS/MS)分析,电喷雾离子化正离子方式(ESI+)及多反应监测模式(MRM)进行测定,基质匹配标准溶液外标法定量。在最优条件下进行测试,所测项目方法的定量限(S/N≥10)均小于0.01mg/kg。在加标水平为0.01mg/kg、0.05mg/kg和0.20mg/kg时,方法回收率为71.1%~112%,相对标准偏差为4.5%~17.8%。
简介:Alowcost8×10-Gb/stransmissionsystemover1500kmonconventionalfiberusingchirpedfiberBragggrating(CFBG)asdispersioncompensatorisdemonstrated.Thebiterrorrate(BER)below10-10at1500kmisobtained.Thechannelspacingis0.8nmandtheopticalamplifierspacingis100km.Only16erbium-dopedfiberamplifiers(EDFAs)areused.
简介:Real-timevideostreamingusingultra-wideband(UWB)technologyisexperimentallydemonstratedalonglong-reachpassiveopticalnetworks(LR-PONs)withdifferentwiredandwirelessreaches.ExperimentaltestsusingexternalanddirectmodulationwithUWBwirelessradiationinthe10-and60-GHzbandsareperformed.Anultra-bendablefiberisalsoconsideredforalast-miledistribution.ThevideoqualityattheoutputoftheopticalfiberinfrastructureoftheLR-PONisassessedusingtheerrorvectormagnitude(EVM),andthelinkqualityindicator(LQI)isusedasafigureofmeritafterwirelessradiation.AnEVMbelow–17dBisachievedforbothexternallyanddirectlymodulatedLR-PONscomprisingupto125kmofopticalfiber.EVMimprovementisobservedforlongerLR-PONswhendirectlymodulatedlasers(DMLs)areusedbecauseoftheamplitudegainprovidedbythecombinedeffectofdispersionandDML’schirp.Comparedwithopticalback-to-backoperation,theLQIleveldegradestothemaximumaround20%forLR-PONsrangingbetween75and125kmoffiberreachandwithawirelesscoverageof2minthe10-GHzUWBband.ThesamelevelofLQIdegradationisobservedusingthe60-GHzUWBbandwithaLR-PONintegrating101kmofaccessnetwork,alast-miledistributionusingultra-bendablefiber,anda5.2-mwirelesslink.