简介:ThedevelopmentofthefogdetectorwasinvestedbytheStatePlanningCommissionandstartedinJuly1997.Theprototype'scalibrationandtestwasconductedin1999.Thereafterthedetectorwasimprovedinthefollowingrespects:Hardware:Inordertoreducetheeffectsofthebackground,thetransmitterandreceiverunitsweredesignedtobedownwards.Ahigh-powerGaAsLEDisusedforthelightsourcesandforincreasingtransmittingpower.Theintensityofthelightismonitoredandstabilizedbyaspecialcircuitinthetransmitterunit,whichreceivesapartoftheemittedlightbyaPIN
简介:文中简要介绍了地理信息系统(GIS)的基本概念和现今农业结构战略性调整的具体内涵,介绍了地理信息系统应用于农业气候区划工作的背景和制作专题农业气候区划的步骤,同时对"3S"集成技术进行了简单的综述.