机动车源大气颗粒物粒径分布及碳组分特征

颗粒物的粒径分布特性与碳质组分的表征已成为大气颗粒物源解析的重要方法.利用微孔均匀沉积式碰撞采样器与有机碳/元素碳分析仪,研究采集自不同区域的机动车源大气颗粒物粒径分布特性及其碳组分含量特征.结果表明,随着粒径级增大,发动机原排颗粒物质量浓度逐渐降低.实验室排空大气颗粒物在0.32~0.56μm粒径级浓度较高;地下停车场大气颗粒物在1.0~1.8μm粒径级浓度较高.柴油机原排颗粒物OC1、OC2和OC3所占比例较多,EC2为元素碳的主要部分.机动车源扩散区域大气颗粒物OC3和OC4含量所占比例较多,地下停车场大气颗粒物EC1占元素碳绝大部分.柴油机原排颗粒物的OC/EC比值较小,在0.92~2.50之间.实验室排空与地下停车场大气颗粒物的OC/EC比值分别在1.40~2.53与2.36~4.82之间.此外,地下停车场大气颗粒物的OC/EC比值均大于2.0,最高可达4.82,可以判定地下停车场有较多的二次颗粒物生成.上述特性可为机动车源大气颗粒物的辨识提供参考依据.     

酸雨胁迫对白兰花(Michelia alba DC．)抗氧化酶活性及丙二醛(MDA)含量的影响

本文以长势良好且树龄相同的木兰科植物白兰花(Michelia alba.DC)为实验材料,采用盆栽方式,用模拟酸雨的处理方法,研究了其在模拟酸雨胁迫下的抗氧化酶系统和丙二醛(MDA)的变化规律。结果表明,pH2.0酸雨比pH3.0和pH4.0对白兰花的影响更大,到第六次喷施酸雨时,SOD、POD、CAT酶活性均低于对照;各处理MDA含量在第六次处理时达到最高值,且均与对照呈显著性差异(P0.05)。说明酸雨胁迫对白兰花的影响较大,白兰花在酸雨胁迫下抗逆性和耐受性较弱,其结果为酸雨控制区选择城市绿化植物提供重要的现实意义。     

机动车污染防治行业发展综述

简述了近几年我国机动车污染防治行业发展的总体概况;介绍了我国机动车排放法规的实施情况,以及机动车污染防治行业发展的现状;总结了机动车污染防治委员会近年来的主要工作;提出了机动车污染防治行业应开展机动车污染防治技术基础研究工作的建议。     

Prenatal diagnosis of charcot-marie-tooth disease type 1a (CMT1A) using molecular genetic techniques

Charcot-Marie-Tooth disease type 1A (CMT1A) is a frequent hereditary motor and sensory neuropathy of the peripheral nerves. In most cases, the disease is associated with a 1.5 Mb tandem duplication at 17p11.2. A 42-year-old pregnant woman requested prenatal diagnosis because of her age and since both her husband and two children were severely affected with CMT1. The CMT1A duplication was demonstrated in the father's, the two children's, and the fetus's DNA using different molecular genetic methods. Although cytogenetical analysis showed a normal female karyotype in the fetus, the parents decided to terminate the pregnancy because of the genetic risk associated with the CMT1A duplication.     

现行城市机动车排放控制法律调整存在的不足与对策

针对目前中国城市机动车高速发展而带来了城市大气环境污染负面问题，分析了现阶段对城市机动车排放控制存在的法律责任界定不清、执法部门权责不明、市场机制运作不完善等缺陷，提出从法律视野进行调整，充分发挥法律的规制功能和权威力量，明确行政主管部门权责，健全机动车从生产-销售-回收以及与石油等部门的市场调节机制，最终促进城市机动车尾气排放得到有效的控制，营造良好的城市环境。     

机动车排气污染控制技术与措施

机动车发动机的有害排放物也成为了造成大气污染的一个主要来源,会给人体健康造成了严重的危害,机动车排气污染控制技术和措施包括发动机净化处理技术控制技术,提高燃油的燃烧率,安装防污染处理设备;还包括行政管理手段,实行综合整治,多措并举,减少或消除机动车尾气中有毒有害气体的排放,减轻对大气环境的污染。     

直线电机轮轨交通系统安全性分析

直线电机轮轨系统采用直线感应电机牵引 ,轮轨系统支承导向 ,是一种在技术、经济、环保方面均具有良好性能的新型城市轨道交通系统。该系统有两种主要技术模式 ,均有良好的安全运营记录。笔者介绍了系统的性能和设计特点 ;从牵引制动系统、控制系统、管理系统、养护维修系统以及防灾系统 5个方面对系统的安全性设计方法进行了总结 ;认为该系统具有良好的安全性能 ,先进的安全管理理念以及健全的安全防护系统 ;特别强调对该系统进行的安全设计研究 ,将为提高我国城市轨道交通系统的安全性提供新的思路     

浅析步进电机的发热与安全

分析了步进电机发热的原因及发热带来的影响，提出了如何减少步进电机发热的方法。     

机动车排放中挥发性有机污染物的组成及其特征研究

应用大气采样罐采样技术和色谱-质谱联用(GC-MS)技术,对广州市环境空气、交通道路、城市隧道和汽车尾气中55种挥发性有机物(VOCs)的组分及其质量浓度水平进行测试,并研究了广州市机动车VOCs排放特征.结果表明:①城区环境空气质量本底观测点白云山摩星岭的大气样品中ρ(VOCs)数量级为10-1～101 μg/m3,其中烷烃类、烯烃类、乙炔和单环芳香烃类平均质量浓度分别为13.97,15.15,6.16和43.27 μg/m3.市区主要交通干道(东风中路、环市中路和新港西路)旁空气样品的ρ(VOCs)数量级为101～102μg/m3,其中烷烃类、烯烃类、乙炔和单环芳香烃类最高质量浓度相应比环境本底质量浓度高约20～30倍.②在怠速条件下检测了摩托车、出租车、大客车、轻型卡车、小轿车和公交车等6种新车和在用车型VOCs的排放,其组成和质量浓度因机动车类型、功率和燃料不同而不同,一般功率越大VOCs排放越严重,ρ(VOCs)数量级大致为10-1～103mg/m3,为交通干道空气ρ(VOCs)的1 000倍以上.其中LPG车具有最高的烷烃类、烯烃类和乙炔排放量,测试样品的ρ(VOCs)分别为815.79～2 001.66,696.84～1 799.10和53.87～416.13 mg/m3.而柴油车排放的VOCs远远低于其他燃料车型.③通过对广州珠江隧道连续48 h的监测,研究了隧道内交通特征、微气象特征和VOCs组成及其质量浓度水平,能够计算出广州机动车55种VOCs化合物的平均排放因子.      

Carbonaceous aerosols in PM10 and pollution gases in winter in Beijing

An intensive observation of organic carbon (OC) and element carbon (EC) in PM10 and gaseous materials (SO2, CO, and O3,) was conducted continuously to assess the characteristics of wintertime carbonaceous aerosols in an urban area of Beijing, China. Results showed that the averaged total carbon (TC) and PM10 concentrations in observation period are 30.2±120.4 and 172.6±198.3 μ/m3, respectively. Average OC concentration in nighttime (24.9±19.6 μ/m3) was 40% higher than that in daytime (17.7±10.9 μ/m3). Average EC concentrations in daytime (8.8±15.2 μ/m3) was close to that in nighttime (8.9±15.1 μ/m3). The OC/EC ratios in nighttime ranging from 2.4 to 2.7 are higher than that in daytime ranging from 1.9 to 2.0. The concentrations of OC, EC, PM10 were low with strong winds and high with weak winds. The OC and EC were well correlated with PM10, CO and SO2, which implies they have similar sources. OC and EC were not well correlated with O3. By considering variation of OC/EC ratios in daytime and night time, correlations between OC and O3, and meteorological condition, we speculated that OC and EC in Beijing PM10 were emitted as the primary particulate form. Emission of motor vehicle with low OC/EC ratio and coal combustion sources with high OC/EC ratio are probably the dominant sources for carbonaceous aerosols in Beijing in winter. A simple method was used to estimate the relative contribution of sources to carbonaceous aerosols in Beijing PM10. Motor vehicle source accounts for 80% and 68%, while coal combustion accounts for 20% and 32% in daytime and nighttime, respectively in Beijing. Averagely, the motor vehicle and coal combustion accounted for 74% and 26%, respectively, for carbonaceous aerosols during the observation period. It points to the motor vehicle is dominant emission for carbonaceous aerosols in Beijing PM10 in winter period, which should be paid attention to control high level of PM10 in Beijing effectively.