简介:Measurementsofparticulatematter(PM),i.e.,PM10,PM2.5,andPMl,havebeenperformedontheCantonTower,alandmarkbuildinginGuangzhou,atheightsof121and454msinceNovember2010,usingaGRIMM180aerosolparticlespectrometer(Germany).AnalysesofdatafromNovember2010toMay2013showedthattheannualaveragevaluesofPM10,PM2.5,andPMlattheobservationheightof121mabovethegroundwere44.1,38.2,and34.9μg/m3,respectively,andthoseat454mabovethegroundwere35.7,30.4,and27.5μg/m3,respectively.ByconsideringthevaluesofthesecondaryconcentrationlimitsgivenintheAmbientAirQualityStandardsissuedin2012,itwasobservedthattheannualaveragevaluesofPM10attheobservationheightsof121and454m,aswellasthoseofPM2.5at454m,reachedthosestandards.Furthermore,theover-standardamplitudeoftheannualaveragevalueofPM2.5attheobservationheightof121mwas9.1%.Duringtheobservationperiod,themaximumdailyaveragevaluesofPM10,PM2.5,andPM1attheobservationheightof121mwere183.3,144.8,and123.8μg/m~3,respectively,andthoseat454mwere102.8,92.7,and86.4μg/m3.ThedailyaveragevaluesofPM10attheobservationheightof454mwerenotabovethestandards.Theover-standardfrequenciesofthedailyaveragevaluesofPM10andPM2.5attheobservationheightof121mwere0.6%and10.7%,respectively,andtheover-standardamplitudeswere9.0%and24.4%,respectively.Theover-standardfrequencyofthedailyaveragevalueofPM2.5attheobservationheightof454mwas2.0%,andtheover-standardamplitudewas10.4%.Accordingly,itcanbestatedthattheairattheobservationheight454mabovethegrounddidnotreachthesecondarylimitofthenewstandards.Thepollutionwasmostseriousduringwinter,andtheairwasrelativelycleanerduringsummer.Overall,theverticaldistributionsofPM10,PM2.5,andPMldecreasedwithheight.Thelapseratesshowedthefollowingsequence:PM10>PM2.5>PM1,whichindicatesthattheverticaldistributionoffineparticles
简介:3-去氮-NeplanocinA(3-DNPA,2)是具有很强抗病毒抗肿瘤活性的碳环核苷。发展其有效的合成路线,有助于其类似物的合成及进一步的生物活性研究。由2,4.二羟基-3-硝基吡啶起始的3-去氮嘌呤合成,采用-釜反应直接构建咪唑环,避免了中间体10被氧化;同时,碱基合成中副产物11.1的发现和结构确证,提示了一条合成1-去氮嘌呤的新方法。采用微波辅助方法提高了6-氯-3-去氮嘌呤12的肼解及随后的Boc保护制备17的反应产率;而后者提高了偶联反应N9异构体的比例。全部合成工作经十步反应得到3-DNPA,总收率11.2%。
简介:摘要物园小建筑用砌块更好,简便易行,在园林坡地上建造较为节省,用方钢构架焊牢在砌块洞中,成为梁、柱连接加固体系,替代山体中的现浇混凝土笼舍,简化了施工,是动物界饲养笼舍的推广性设计方式。