简介:PM_(1.0)(好粒子,与直径<1μm),PM_(2.5)(好粒子,与直径<2.5μm)并且PM_(10)(粗糙的粒子,与直径<10μm)是在香港的一条高交通的道路附近的测量at24小时间隔,从2004年10月到2005年9月。Massconcentrations为三粒子部分被决定,平均为PM_(1.0),PM_(2.5)和PM_(10),分别地44.5±18.4,55.4±25.5和81.3±37.7μg·m~(-3)。PM_(2.5)是3.7times美国EPA“s15μg·m~的年度NAAQS(-3)。总的来说,PM_(1.0)占了44~69%(一般水准57%)PM_(10),当PM_(2.5)占了58~82%时,(一般水准71%)在这学习。Theparticulate群众在冷季节与高集中显示出明显的季节的模式并且在温暖的季节低,PM_(2.5-10)的特别高的集中在冷季节期间。PM_(2.5)的集体集中的Diurnalvariations在7月期间是坚定的,证明二个学生在早上和下午上下班时间达到顶点。
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:ThisstudyinvestigatesthecorrelationbetweenPM10andmeteorologicalfactorssuchaswindspeed,atmosphericvisibility,dewpoint,relativehumidity,andambienttemperatureduringabrownhazeepisode.InordertoidentifythepotentialsourcesofPM10duringbrownhazeepisode,respirableparticulatematter(PM10)wascollectedduringbothnon-hazedaysandhazedaysandfurtheranalyzedformetallicelements,ionicspecies,andcarbonaceouscontents.Amongthem,ionicspeciescontributed45-64%toPM10,whilemetallicelementscontributed7-21%toPM10whichwassmallerthantheotherchemicalconstituents.TheaverageOC/ECratio(42)inhazedayswasaboutthreetimesoftheaverageOC/ECratio(14)innon-hazedays.Byusingchemicalmassbalance(CMB)receptormodel,themajorsourceswereapportioned,includingtraffics,incinerators,coalcombustion,steelindustry,petrochemicalindustry,andsecondaryaerosols,etc.ThecontributiontoPM10concentrationofeachsourcewascalculatedforallthesamplescollected.TheresultsshowedthatcoalcombustionwasthemajorsourceofPM10innon-hazedaysandsecondaryaerosolswerethemajorsourceinhazedays,followedbypetrochemicalindustry,incinerators,andtraffics,whileothersourceshadnegligibleeffect.
简介:由于液浮陀螺仪常规测试方法偏重于正常陀螺性能参数的测试以及试验条件脱离实际使用状态,常使存在缺陷的陀螺无法准确筛选出来。为了弥补液浮陀螺仪常规测试方法不足,提高陀螺仪的检测可靠性,在常规试验的基础上增加了浮子迟滞试验。对浮子迟滞试验检测技术从试验机理和技术实现上进行了较为详细的分析和研究。在力矩反馈测试系统反馈放大器的输入端施加高精度三角波信号,在陀螺仪浮子沿输出轴在选定的角度范围内周期性缓慢匀速摆动过程中完成了陀螺力矩、阻尼力矩、角弹性力矩、常值干扰力矩及摩擦型干扰力矩的检测。利用浮子迟滞试验技术在液浮陀螺仪多余物检测以及最佳工作温度优选方面取得了很好的实用效果,是提高陀螺仪性能检测可靠性和故障定位准确性的一种关键检测技术。
简介:针对多星座情况下多卫星同时故障时的接收机自主完好性检测的问题,分析了多卫星同时故障的原因及特点,提出基于极大似然比的分层完好性检测方法。通过奇偶向量矩阵的计算,根据极大似然估计,进行故障检测与隔离,利用全量检验统计值与部分检验统计值之间的关系进行故障卫星的确定,并利用接收机的数据进行仿真验证。仿真结果表明,本方法可以快速有效地实现多星座情况下的接收机自主完好性检测,检测出并隔离故障卫星。
简介:移动机器人的目标检测要求其对特定的静止或运动物体进行运动分析及检测。以Voyager-III移动机器人系统为研究对象,实现非理想光照下,对橘红色目标足球的运动检测。提出在传统三帧差分法基础上,先利用Markowitz投资组合模型进行足球目标的特征提取,将场地非感兴趣的目标中,出现全部像素值发生变化的目标去除,再进行图像帧间差分。利用CCD摄像机对比赛环境中足球的运动轨迹进行录制,选取具有代表性的各帧视频图像、Markowitz算法优化后的差分图像和跟踪图像,结果表明跟踪图像不含非目标物的干扰,克服了差分图像存在空洞的问题,为移动机器人提供了一种实用的运动目标检测方法。