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471.
生物-微电解组合工艺处理染料废水研究   总被引:1,自引:0,他引:1  
采用上流式污泥床过滤器(upflow blanket filter,UBF)+曝气生物滤池(biological aerated filter,BAF)+微电解的组合工艺,对盐度接近2%、色度和COD分别约为8000倍和600.5mg/L的染料废水进行处理。经过连续120d的稳定运行后,组合系统处理效果良好,脱色率和COD去除率分别达到99%和75%以上。UBF和微电解单元均可以大幅度提高废水的可生化性,有利于进一步的生物处理。UV—Vis扫描和GC—MS分析表明,该组合工艺能破坏染料的发色基团和共轭双键,并能高效降解原水中的酚类、氯代有机物和复杂的杂环类化合物。实验结果表明,UBF+BAF+微电解的组合工艺是处理染料废水的一种有效方法。  相似文献   
472.
Over the past decade, the emission standards and fuel standards in Beijing have been upgraded twice, and the vehicle structure has been improved by accelerating the elimination of 2.95 million old vehicles. Through the formulation and implementation of these policies, the emissions of carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOx), and fine particulate matter (PM2.5) in 2019 were 147.9, 25.3, 43.4, and 0.91 kton in Beijing, respectively. The emission factor method was adopted to better understand the emissions characteristics of primary air pollutants from combustion engine vehicles and to improve pollution control. In combination with the air quality improvement goals and the status of social and economic development during the 14th Five-Year Plan period in Beijing, different vehicle pollution control scenarios were established, and emissions reductions were projected. The results show that the emissions of four air pollutants (CO, VOCs, NOx, and PM2.5) from vehicles in Beijing decreased by an average of 68% in 2019, compared to their levels in 2009. The contribution of NOx emissions from diesel vehicles increased from 35% in 2009 to 56% in 2019, which indicated that clean and energy-saving diesel vehicle fleets should be further improved. Electric vehicle adoption could be an important measure to reduce pollutant emissions. With the further upgrading of vehicle structure and the adoption of electric vehicles, it is expected that the total emissions of the four vehicle pollutants can be reduced by 20%-41% by the end of the 14th Five-Year Plan period.  相似文献   
473.
分析了氨氮对污水场的冲击影响,并提出对策。  相似文献   
474.
极谱催化波法测定痕量亚硝酸根的研究   总被引:1,自引:0,他引:1  
在含稀硫氰酸盐的底液中 ,在单扫示波极谱仪上 ,有一灵敏的亚硝酸根催化波。峰电位为 -0 .47V( vs·SCE)。阳极化二阶导数峰高与亚硝酸根浓度在 1× 10 - 7~ 5× 10 - 5mol/L 之间成线性关系。检测限达 5× 10 - 5mol/L( 2 .3ppbNO - 2 )。试验了多种共存离子对测定的影响 ,表明该法具有较好的选择性 ,尤其是大量硝酸根不干扰。应用该法测定了许多样品中的亚硝酸根 ,并对该波的机理进行了研究 ,结果证明该波是 [SCN· NO]催化溶液中的溶解氧还原所致  相似文献   
475.
保山市空气污染趋势与防治措施   总被引:2,自引:0,他引:2  
对近10年保山市主要空气污染物浓度变化规律、发展趋势、空间分布、污染特征及污染与气象的关联度等进行了综合分析研究,并据以提出了防治对策。  相似文献   
476.
在对我国生物多样性保护的政策和体制进行详细阐述的基础上分析其中存在的主要问题,提出改进建议.首先分析了生物多样性保护的实质,认为所谓生物多样性保护就是通过有意识地限制和调节人类活动对生物的干扰破坏,使地球上的生物多样性得以保持和恢复.因此,在本质上,生物多样性保护就是要协调人与自然之间业已失衡的关系,其目标在于实现人与自然之间的和谐和可持续发展.其后,讨论了我国生物多样性保护面临的主要挑战,指出巨大的人口压力和剧烈的人类活动是造成生物多样性破坏的主要原因.特别针对保护体制中的多部门管理和协调机制、中央和地方政府的责任和义务、保护区设立和管理以及国际合作等方面进行了分析,指出了在多头管理的体制下,各部门职责、权利和资源分配不明确、不匹配,保护区管理中重减轻管、事企合一等问题.最后,提出了相应的政策建议.  相似文献   
477.
NOx emission abatement catalysts V2O5 supported on various TiO2 including anatase, rutile and mixture of both were investigated with various physico-chemical measurements such as BET, NH3-TPD, NARP, XRD and so on, and the effect of TiO2 surface properties on the SCR (selective catalytic reduction) activity of V20s/TiO2 catalysts was studied. It was found that the TiO2 surface properties had strong affect on the SCR activity of V2Os/TiO2 catalysts. The stronger acidic property resulted in the higher exposure of active sites as well as the higher SCR activity.  相似文献   
478.
柴达木盆地水资源决策支持系统的设计与开发研究   总被引:4,自引:0,他引:4  
柴达木盆地水资源规划管理决策属典型的半结构化、多层次、多决策者和多目标的决策问题,为此设计开发了柴达木盆地水资源决策支持系统。文章系统地介绍了柴达木盆地水资源决策支持系统结构框架、设计原则、开发思路、决策模式和基本功能。系统由数据库、模型库及其管理系统三部分组成,模型库包括人口动态模型、宏观经挤模型、水资源模拟模型、绿洲生态需水模型和水资源多目标优化分析模型等5个基本模型。在求解水资源多目标优化分析模型时,使用了逐步法(STEM),把多目标化为单目标进行求解,决策者在迭代权衡过程中输入经验与偏好信息来获取满意的决策信息。  相似文献   
479.
Objective: This article investigated and compared frequency domain and time domain characteristics of drivers' behaviors before and after the start of distracted driving.

Method: Data from an existing naturalistic driving study were used. Fast Fourier transform (FFT) was applied for the frequency domain analysis to explore drivers' behavior pattern changes between nondistracted (prestarting of visual–manual task) and distracted (poststarting of visual–manual task) driving periods. Average relative spectral power in a low frequency range (0–0.5 Hz) and the standard deviation in a 10-s time window of vehicle control variables (i.e., lane offset, yaw rate, and acceleration) were calculated and further compared. Sensitivity analyses were also applied to examine the reliability of the time and frequency domain analyses.

Results: Results of the mixed model analyses from the time and frequency domain analyses all showed significant degradation in lateral control performance after engaging in visual–manual tasks while driving. Results of the sensitivity analyses suggested that the frequency domain analysis was less sensitive to the frequency bandwidth, whereas the time domain analysis was more sensitive to the time intervals selected for variation calculations. Different time interval selections can result in significantly different standard deviation values, whereas average spectral power analysis on yaw rate in both low and high frequency bandwidths showed consistent results, that higher variation values were observed during distracted driving when compared to nondistracted driving.

Conclusions: This study suggests that driver state detection needs to consider the behavior changes during the prestarting periods, instead of only focusing on periods with physical presence of distraction, such as cell phone use. Lateral control measures can be a better indicator of distraction detection than longitudinal controls. In addition, frequency domain analyses proved to be a more robust and consistent method in assessing driving performance compared to time domain analyses.  相似文献   

480.
Polycyclic aromatic hydrocarbons (PAHs) are a typical class of persistent organic pollutants that is ubiquitous worldwide. Previous animal studies suggested that PAHs had adverse effects on female reproduction. However, the human data regarding relationship of PAHs exposure with women reproductive health, such as ovarian dysfunction, are scarce. In this case-control study, the associations of serum levels of PAHs with the risk of premature ovarian failure (POF) and reproductive hormones in Chinese women were investigated, with recruiting 157 POF patients and 217 healthy women. The serum levels of 12 types of PAHs, as well as reproductive hormones, including follicle-stimulating hormone, luteinizing hormone and anti-mullerian hormone, were determined. In the logistic regression models, most individual PAH congeners showed significantly positive correlations with the risk of POF (p < 0.05), except for fluorine and pyrene. Benzo(a)pyrene (BaP), as the most carcinogenic PAH congener, was observed to be significantly positively associated with the risk of POF. After adjustment for age, body mass index, educational levels and household income, per one-unit increase in the log-transformed BaP concentration was significantly correlated with 2.191-fold increased risk of POF (OR = 2.191, 95%CI: 1.634–2.938, p < 0.05). To the best of our knowledge, this is the first study to report an association between internal exposure levels of PAHs and the increased risk of POF in women.  相似文献   
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