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741.
Chengzhen Bao Pengfei Chai Hongbo Lin Zhenyu Zhang Zhenhua Ye Mengjia Gu 《Journal of the Air & Waste Management Association (1995)》2016,66(12):1202-1213
Recently, air pollution has attracted a substantial amount of attention in China, which can be influenced by a variety of factors, but the association between air pollution and human activity is not quite clear. Based on real-time online data (January 1, 2014, to December 31, 2014) of air pollution and meteorology reported by official sites, and demographic, economic, and environmental reform data in a statistical yearbook, the influences of meteorological factors (temperature, relative humidity, precipitation intensity, and wind force) and human activities on PM2.5 pollution were explored. After correlation analysis, logistic regression analysis, and a nonparametric test, weak negative correlations between temperature and PM2.5 pollution were found. In most cases, festival and morning peak hours were protection and risk factors of PM2.5 pollution, respectively. In addition, government actions, such as an afforestation project and increasing financial expenditure for energy saving and environmental protection, could greatly contribute to alleviating pollution of PM2.5. The findings could help officials formulate effective laws and regulations, and then PM2.5 pollution related to the pattern of human activity would be ameliorated.
Implications: Most of the time, festival and morning peak hours are protection and risk factors for PM2.5 pollution, respectively. Increasing the percentage of afforestation area and financial expenditure for energy saving and environmental protection could significantly reduce PM2.5 pollution. The findings can help officials formulate effective laws and regulations, and then PM2.5 pollution related to the pattern of human activity, especially government action, will be ameliorated. 相似文献
742.
利用水泥的水化过程易受有机物影响的特点,采用硅酸盐水泥深度处理了垃圾渗滤液膜生物反应器(MBR)工艺出水,考察了不同因素,如投加量、初始pH、反应时间及振荡速率等对于渗滤液尾水中有机物的去除效果以及最佳工艺条件,并分析了渗滤液尾水中有机物的去除机理。结果表明,水化过程对渗滤液尾水中的有机物去除性能良好,且对不同有机物具有一定的选择性,尤其对具有近紫外区(200~400 nm)吸收峰特征的有机物去除效果更佳,同时发现,当投加量为50 g/L、pH=8.3(原渗滤液pH)、反应时间为24 h和振荡速度为200 r/min时,去除效果最佳,其COD、TOC和UV254的平均去除率分别达到55.6%、62.1%和68.8%。 相似文献
743.
Escherichia coli is known to respond to certain toxic chemicals through an increased expression of various stress genes. In this study, therefore, the expression of recA, katG, fabA and grpE genes was used as a representative for DNA, oxidative, membrane and protein damage, respectively, after E. coli was exposed to different polycyclic aromatic hydrocarbons (PAHs), i.e., phenanthrene, naphthalene and benzo[a]pyrene. To accomplish this, the expression levels of these four genes were quantified using a real-time RT-PCR analysis when E. coli cultures were under stressful conditions, such as those caused by an exposure to mitomycin C, hydrogen peroxide and phenol. It was found that the primary toxic effect of each chemical is clearly seen when the expression levels of the different genes are compared. Tests with the PAHs showed naphthalene and benzo[a]pyrene to be genotoxic, while phenanthrene had no clear effect on the expression of any of these genes. Based on these results, the effects due to these toxic chemicals and the extent of each stress can be evaluated with ease using the expression levels of different stress responsive genes. 相似文献
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746.
基于遥感数据的渤海海冰灾害风险研究 总被引:4,自引:0,他引:4
从海冰带来的严重灾害问题出发,针对传统监测方法的局限性,阐述了遥感技术在海冰灾害监测中的优越性.以渤海海冰为例,提出一种海冰灾害风险等级划分方法,即利用遥感技术和地理信息系统制作经纬度间隔为0.2°的网格,然后得到渤海海冰密集度,选择最大冰密集度、平均冰密集度、冰厚和冰期作为等级划分的指标.根据现场观测和多年调查研究,把海冰灾害风险程度分为3个等级零风险、低风险和高风险.结果表明该指标能够反映海冰灾害的风险程度,用该方法描述海冰灾害风险等级可以为海洋预报提供依据. 相似文献
747.
Researches on modified Fenton reactions applied in phenol degradation have been focused on reducing secondary pollution and enhancing catalytic efficiency. Newly developed methods utilizing carriers, such as Resin and Nafion, to immobilize Fe(2+) could avoid iron ion leakage. However, the requirement of high temperature and the limited reaction efficiency still restrained them from broad application. Based on a recently discovered "hidden talent" of ferromagnetic nanoparticles (MNPs), we established a MNP-catalyzed phenol removal assay, which could overcome these limitations. Our results showed that the MNPs removed over 85% phenol from aqueous solution within 3h even at 16 °C. The catalytic condition was extensively optimized among a range of pH, temperature as well as initial concentration of phenol and H(2)O(2). TOC and GC/MS analysis revealed that about 30% phenol was mineralized while the rest became small molecular organic acids. Moreover the MNPs were thermo-stable and could be regenerated for at least five rounds. Thus, our findings open up a wide spectrum of environmental friendly applications of MNPs showing several attractive features, such as easy preparation, low cost, thermo-stability and reusability. 相似文献
748.
中国茸鹿品种(品系)的随机扩增多态DNA(RAPD)研究 总被引:8,自引:0,他引:8
采用随机扩增多态DNA技术研究了5个茸鹿品种(品系)75个个体的遗传变异关系。在所使用的41个引物中,有40个引物扩增出多态谱带,共检测到395条扩增片段,其中259条(65.6%)出现变异,用Shaknnon指数计算了5个品种(品系)的遗传变异及其遗传变异在群体内和群体间的分布。利用Nei氏片段共享度计算了75个个体间的遗传距离,用UPGMA聚类法构建了75个个体的系统发育树状图,反映5个茸鹿品 相似文献
749.
750.
聚硅酸铝铁絮凝剂的制备及其在印染废水处理中的应用 总被引:2,自引:1,他引:1
以粉煤灰为主要原料制备了聚硅酸铝铁絮凝剂。通过L16(45)正交实验得出粉煤灰中Al3+和Fe3+的最佳浸取实验条件为焙烧温度900℃,m(Na2CO3)∶m(粉煤灰)=0.10,浸取温度为70℃,盐酸质量分数20%,浸取时间为2.0h。通过L9(34)正交实验得出聚硅酸铝铁的最佳制备条件为n(聚硅酸)∶n(Al3+)=1∶0.5,n(聚硅酸)∶n(Fe3+)=1∶0.5,浸出液pH为5.0,熟化温度为60℃。利用制得的聚硅酸铝铁絮凝剂对200mL模拟印染废水进行处理,在絮凝剂加入量为4mL时絮凝效果最好,透光率超过70%。 相似文献