简介:1前言短波单边带数传系统是"9210"工程业务系统的重要组成部分,在"9210"工程实施过程中,我中心承担了短波单边带电台的技术验收工作,由于所采用的FT-80C型电台在业务使用中主要承担数传任务,因此对电台的部分技术指标有一定特殊要求:发射机载波频率误差≤10Hz、接收机调制接收带宽≥2.6kHz.
简介:BasedonChina'smonthlyprecipitationdatafrom1950to2000andbyusingtheZ-index,4categoriesoffloodwereestimated.VariationandchangeoffloodinSouthChinawereanalyzedintermsofpercentageareasofflood.ThisstudyrevealsthatfloodareasinSouthChinahadaslightlydecreasingtrendinthelatest50years.Duringthewinterhalfyear,however,itdisplayedanincreasingtrend,especiallysincethe1990's.ItisalsofoundthatfloodareasdecreasedduringthesummerhalfyearfromApriltoSeptember,butincreasedduringsummer,especiallysincethe1990's.Intheannuallyfirstseasonofprecipitation,thefloodareahasadecreasingtrend,butithasastronglyincreasingtrendintheannuallysecondseason.Thegradualwettrendduringthewinter-halfyearresultsinwetterclimateconditionforSouthChina,whichwillbemorefavorableforspreadingsomeoftheepidemicpathogenicbacterium,cropdiseasesandinsectpests.