2008～2017年北京市PM2.5周期性变化特征与影响机制

利用Morlet小波方法分析北京市2008~2017年PM_2.5资料,结果表明,北京市PM_2.5浓度存在显著的日变化、周变化、以及季节和年变化周期性特征,并且秋冬季的周期性特征显著高于春夏季.结合气象资料,包括水平风速、大气边界层高度、以及大气稳定度指数等,分析PM_2.5不同周期性变化对应的主要影响机制表明：大气边界层过程是PM_2.5日变化的主要影响机制,导致PM_2.5浓度白天低、夜间高.秋冬季PM_2.5日变化幅度高于春夏季;天气过程是PM_2.5周变化的主要机制,PM_2.5浓度与天气变化过程带来的风速变化和边界层高度呈强反相关关系;PM_2.5的季节变化与大气扩散能力的季节变化密切相关,秋冬季减弱的大气扩散能力加速了PM_2.5在近地面累积,春夏季则相反.     

关注建筑业职工的劳动保护

几年来,建筑施工企业各项规章制度都较为完善,按照企业标准化、规范化的管理模式运作,安全生产、劳动保护工作,在企业是一项重要工作,企业的工会组织与行政部门紧密配合,加大了安全生产管理力度,建立了“职工代表视察制度“、“安全生产责任制“、“安全生产教育制度“、“安全检查制度“、“安全生产奖惩制度“、“职工因工伤亡事故报告统计调查及处理制度“、“班组安全生产制度“、“项目施工安全生产制度“、“职工安全生产培训制度“等一系列制度,并且层层签订“安全生产责任状“,确保责任落实到人,建立了安全生产、劳动保护管理的长效机制.企业在与职工签订劳动合同中包含了安全生产、劳动保护条款.……     

浙西南丘陵山区沟谷泥石流降雨特征分析

浙西南丘陵山区沟谷泥石流均为暴雨型泥石流,降水是诱发泥石流灾害的主要因素。通过对暴雨与泥石流发生的时间关系分析,认为泥石流发生主要有两种类型:一是当日降雨量直接激发泥石流,另一种是泥石流发生在有一定前期降雨的积累,并利用雨量站观测资料对这两种类型泥石流发生时的降雨特征进行了详细分析,以为泥石流灾害的防治提供依据。     

HAZOP分析技术在邻甲酚反应单元的应用

运用HAZOP分析技术对邻甲酚反应单元进行危险性分析,分析了邻甲酚反应单元中有意义的偏差、偏差发生的原因、可能导致的后果,并提出了相应的建议措施.从分析效果来看,HAZOP技术能系统地辨识邻甲酚反应单元存在的隐患,有助于提高装置工艺安全水平,为邻甲酚生产装置的安全操作提供依据.     

烟气脱硝装置臭氧腐蚀性安全评估

根据烟气脱硝装置工艺特点,利用臭氧腐蚀性测试装置,开展了金属材质的腐蚀性研究。通过扫面电镜对不同材质腐蚀前后的表面形貌进行表征,确定了臭氧对不同材质的腐蚀特性,通过理论计算确定了臭氧分解的绝热温升。结合脱硝装置工艺特点对氧气管道流速控制方面进行了分析和总结,根据分析结果给出了建议。     

应用~(32)P示踪技术研究不同土壤慢速土地处理系统内磷素的行为规律

应用放射性32 P示踪技术 ,在人工模拟土柱装置上 ,对城市污水中的磷素在不同土壤内的行为规律进行研究 ,并对实验数据进行了归一化的计算处理 ,结果表明红壤和紫色土对城市污水中的磷素都有较强的去除能力 ,但磷素在不同土壤中的行为有明显差异。     

维生素C二步发酵中L-山梨糖脱氢酶的性质及作用

从氧化葡萄糖酸杆菌细胞质中分离纯化出L 山梨糖脱氢酶 (SDH) ,其分子量为 46× 10 3 ,表观分子量为 190× 10 3 ;在测试范围内 ,最适pH是 7.4,温度为 5 5℃ ,最稳定的 pH是 7.0 ,温度为 30℃以下 ;FeCl3 促进酶活 ,CoCl2 抑制酶活 .该酶活力与发酵产物 2 酮基 L 古龙酸的合成呈正相关 ;伴生菌促进产酸菌生长和代谢 ,并使该酶比活力增加 ,从而提高发酵系统中该酶的总活力 .图 11表 5参 9     

中国高温热浪对碳排放量的响应

基于中国碳核算数据及气象资料,分析了8大经济区(30个省份)近20a来(1997～2017年)碳排放量和高温热浪的本底变化特征,探讨了不同区域高温热浪对碳排放量的多尺度响应关系.结果表明:(1)研究时段内,8个经济区的碳排放量均显著增加,增速最大和最小的经济区分别为黄河中游和西北;(2)不同级别(轻度、中度和重度)高温...     

Characteristics and source apportionment of VOCs measured in Shanghai,China

Volatile organic compounds (VOCs) were measured from 2007 to 2010 at the center of Shanghai, China. Because VOCs are important precursors for ozone photochemical formation, detailed information of VOC sources needs to be investigated. The results show that the measured VOC concentrations in Shanghai are dominated by alkanes (43%) and aromatics (30%), following by halo-hydrocarbons (14%) and alkenes (6%). Based on the measured VOC concentrations, a receptor model (PMF; positive matrix factorization) coupled with the information related to VOC sources (the distribution of major industrial complex, meteorological conditions, etc.) is applied to identify the major VOC sources in Shanghai. The result shows that seven major VOC sources are identified by the PMF method, including (1) vehicle related source which contributes to 25% of the measured VOC concentrations, (2) solvent based industrial source to 17%, (3) fuel evaporation to 15%, (4) paint solvent usage to 15%, (5) steel related industrial production to 12%, (6) biomass/biofuel burning to 9%, and (7) coal burning to 7%. Furthermore, ozone formation potential related to VOC sources is calculated by the MIR (maximum incremental reactivity) technique. The most significant VOC source for ozone formation potential is solvent based industrial sources (27%), paint solvent usage (24%), vehicle related emissions (17%), steel related industrial productions (14%), fuel evaporations (9%), coal burning (6%), and biomass/biofuel burning (3%). The weekend effect on the VOC concentrations shows that VOC concentrations are generally higher in the weekdays than in the weekends at the sampling site, suggesting that traffic conditions and human activities have important impacts on the VOC emissions in Shanghai.     

Effects of manganese-toxicity on immune-related organs of cocks

Manganese (Mn) is a trace element known to be essential for maintaining the proper function and regulation of many biochemical and cellular reactions. However, little is known about the effect of excessive amounts of Mn in immune damage of birds. The aim of this study was to investigate the effect of dietary Mn on immune damage in birds. 50-day-old male Hy-line cocks were fed either a commercial diet or a Mn-supplemented diet containing 600, 900, and 1800 mg kg^?1 MnCl₂. After being treated with Mn for 30, 60 and 90 d, the serum and immune organs (spleen, thymus, and bursa of Fabricius (BF)) were collected respectively and examined for Mn contents, activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), malondialdehyde (MDA) contents, ability to resist OH. In addition, DNA damage and apoptosis were observed in cock immune system treated with Mn. The results showed that the contents of Mn and MDA in immune organs and serum were increased, while the activities of SOD, GSH-Px, and ability to resist OH were decreased in the Mn treatment groups. The extensive damage was observed in the immune organs. DNA single strand break and DNA–protein crosslink showed time and dosage effect in lymphocytes of immune organs. It indicated that Mn exposure resulted in oxidative damage of birds immune system by altering antioxidant defense enzyme systems, lipid peroxidation, and apoptosis.