过敏症状儿童室内PM_(2.5)对小鼠巨噬细胞的氧化损伤及VE的抗氧化保护作用研究

越来越多的研究提示,主要空气污染物PM_(2.5)暴露浓度的升高与儿童过敏性疾病的发病率有着密切的关系,然而PM_(2.5)暴露与过敏性疾病之间的关联尚未完全阐明。为探究患有过敏症状儿童的室内PM_(2.5)对小鼠巨噬细胞的氧化损伤作用以及维生素E(vitamin E,VE)的抗氧化保护作用,从5户患有1种或1种以上的过敏性症状(如过敏性鼻炎、哮喘)儿童的室内采集PM_(2.5),分别考察了不同剂量PM_(2.5)暴露24 h后如何影响小鼠巨噬细胞的氧化应激水平,指标包括活性氧(ROS),还原型谷胱甘肽(GSH),丙二醛(MDA),8-羟基脱氧鸟苷(8-OH-dG),以及炎症因子水平,指标包括肿瘤坏死因子ɑ(TNF-ɑ),白介素8β(IL-8β)的影响。结果表明,200μg·mL~(-1)PM_(2.5)暴露组与对照组比较,细胞内ROS积累,出现脂质过氧化以及DNA损伤,并伴有炎症反应的发生,差异均有统计学意义(P0.05或P0.01);VE(50 mg·mL~(-1))+200μg·mL~(-1)PM_(2.5)组的ROS、MDA、8-OHdG、TNF-ɑ、IL-8β含量低于200μg·mL~(-1)PM_(2.5)组,GSH含量高于200μg·mL~(-1)PM_(2.5)组。较高剂量(200μg·mL~(-1))PM_(2.5)可诱导小鼠腹腔巨噬细胞出现氧化损伤,VE在该应激过程中起着一定的保护作用。     

巢湖流域典型环境介质溶解有机质光谱特征及其环境指示意义

溶解有机质（DOM）广泛存在于流域范围内不同环境介质中,并能发生迁移转化.以巢湖流域典型环境（农田土壤、浮游藻类、水生植物和沉积物） DOM样品为研究对象,利用紫外-可见光光谱和三维荧光光谱技术揭示不同环境DOM样品的组成特征,探究流域范围内不同环境介质间DOM可能迁移、转化过程及其环境行为与生态效应.结果表明,巢湖流域典型环境样品单位质量可溶性有机碳（DOC）含量均值从大到小的顺序为：浮游藻类（26701.59 mg·kg^-1）>水生植物（9331.00 mg·kg^-1）>土壤（204.93 mg·kg^-1）≈沉积物（141.13 mg·kg^-1）.与DOC含量类似,280 nm处吸光系数（a₂₈₀值）和总荧光强度均表现为：浮游藻类>水生植物>土壤≈沉积物,且沉积物和土壤DOM样品的重均分子量、芳香性、腐殖化程度均与水生植物和浮游藻类DOM样品具有显著性差异.在此基础上,本文提出了流域层面不同环境介质之间DOM的迁移转化概念模型,结果显示,流域范围内不同环境介质间DOM的迁移转化改变了其组成特征,进而导致生态效应发生改变.上述研究结果为流域环境质量提升和生态效应调控提供了一种新思路.     

下垫面输入资料对深圳气象场及大气扩散能力模拟的影响

区域气象模式的输入资料更替相对城市化发展的实际态势存在滞后,使得空气质量预报模型受气象场模拟性能限制而难以准确预报污染事件.本文以深圳市的WRF模拟为例,对模式土地利用输入资料、城市冠层输入参数进行改进,通过提高气象场的模拟能力,探究下垫面输入资料对深圳气象场及大气扩散能力模拟的影响.结果表明,土地利用输入资料的更新使得城市建成区类型格点模拟温度在1月下降了0.05℃,在4、7和10月分别上升了1.1、0.4和0.5℃;风速在1、4、7和10月分别下降了2.3、1.8、1.9和1.8 m·s^-1;相对湿度分别下降了16.1%、9.0%、14.4%和6.5%;感热通量分别升高了85.3、73.6、134.8和65.6 W·m^-2;潜热通量分别下降了65.9、39.5、118.3和45.7 W·m^-2.土地利用输入资料更新后,深圳市扩散指数在空气质量为"优"、"良"、"轻度污染"时段内,分别下降了约25%、20%、30%,风向变化因子分别约有5%、5%的降低和20%的升高;输入城市冠层参数后,扩散指数分别下降了约25%、15%、5%,风向变化因子分别约有5%的降低、5%和5%的升高.土地利用输入资料的更替和城市冠层参数的输入带来模拟能力的改进,更好地重现了一些复杂的边界层热动力结构,包括典型污染日午后深圳市上空南侧上升、北侧下沉的城市热岛环流和近地面的海风局地环流.     

变频调速PLC群控系统在消防供水系统中的应用

介绍了日本三菱公司生产的FXON60MR·PLC可编程控制器与FHF15K型变频器、SR70型智能PID控制器的组合在中原油气高新股份有限公司天然气处理厂消防供水系统中的应用。通过制定合理的控制方案实现了消防供水的全自动控制,并通过控制功能的设置实现较为复杂的系统开发和应用。     

水灰比对高温下混凝土质量损失及抗压强度影响试验研究

为研究水灰比对不同温度作用下混凝土残余抗压强度、质量损失的影响,对不同受火温度和不同水灰比的混凝土标准立方体试件进行高温下及高温后的抗压强度试验和质量损失测试。试验结果表明:随着水灰比的增大,高温下及高温后混凝土抗压强度、混凝土质量损失均呈现出整体下降的趋势。通过试验拟合回归分析,建立了高温下混凝土抗压强度、质量损失与受火温度之间的关系式,可通过质量损失、受火温度来预估高温下混凝土残余抗压强度。     

Effects of catholyte conditioning on electrokinetic extraction of copper from mine tailings

Effect of electrokinetic treatment on copper partitioning and distribution in mine tailings were studied. In particular the effects of catholyte enhancement by HAc-NaAc, HCl, HAc-NaAc+EDTA and lactic acid+NaOH were evaluated. The results show that conditioning the catholyte plays a very important role in improving Cu removal. When HAc-NaAc is used in the catholyte, the removal percentage of total Cu from the mine tailings sample reached 12.3% under 40 V in 15 days of treatment. The removal percentage of Cu increased to 31.2% when EDTA was used together with HAc-NaAc in the catholyte. At the same time, increasing the applied voltage and treatment time result in an increase in the Cu removal from the mine tailings. Compared with HAc-NaAc (pH=3.52), the use of lactic acid+NaOH (pH=3.15) in the catholyte resulted in better performance in Cu removal from the mine tailings. HCl treatment resulted in removal of about 17.5% of Cu from the mine tailings; however, it resulted in production of significant amounts of toxic chlorine gas. Copper partitioning in the mine tailings was analyzed before and after the electrokinetic treatments. The analysis was conducted using 0.25 mol/l MgCl2 and 0.5 mol/l HCl as extractants, consequently, to assess the mobility of Cu after treatment. The results showed that lowering the pH of the mine tailings increased the exchangeable Cu fraction (or the portion extracted by MgCl2). Accordingly, further acidification results in an increased mobility of Cu and increase in the environmental risk of mine tailings.     

Identifying relationships between baseflow geochemistry and land use with synoptic sampling and R-mode factor analysis

The relationship between land use and stream chemistry is often explored through synoptic sampling of rivers at baseflow conditions. However, baseflow chemistry is likely to vary temporally and spatially with land use. The purpose of our study is to examine the usefulness of the synoptic sampling approach for identifying the relationship between complex land use configurations and stream water quality. This study compares biogeochemical data from three synoptic sampling events representing the temporal variability of baseflow chemistry and land use using R-mode factor analysis. Separate R-mode factor analyses of the data from individual sampling events yielded only two consistent factors. Agricultural activity was associated with elevated levels of Ca2+, Mg2+, alkalinity, and frequently K+, SO4(2-), and NO3-. Urban areas were associated with higher concentrations of Na+, K+, and Cl-. Other retained factors were not consistent among sampling events, and some factors were difficult to interpret in the context of biogeochemical sources and processes. When all data were combined, further associations were revealed such as an inverse relationship between the proportion of wetlands and stream nitrate concentrations. We also found that barren lands were associated with elevated sulfate levels. This research suggests that an individual sampling event is unlikely to characterize adequately the complex processes controlling interactions between land use and stream chemistry. Combining data collected over two years during three synoptic sampling events appears to enhance our ability to understand processes linking stream chemistry and land use.     

Derivation of 137Cs deposition density from measurements of 137Cs inventories in undisturbed soils

The 137Cs inventories in undisturbed soils were measured for 292 locations across the territory of Vietnam. The logarithmic inventory values were regressed against characteristics of sampling sites, such as geographical coordinates, annual rainfall and physico-chemical parameters of soil. The regression model containing latitude and annual rainfall as determinants could explain 76% of the variations in logarithmic inventory values across the territory. The model part was interpreted as the logarithmic 137Cs deposition density. At the 95% confidence level, 137Cs deposition density could be predicted by the model within +/- 7% relative uncertainty. The latitude mean 137Cs deposition density increases northward from 237 Bq m(-2) to 1097 Bq m(-2), while the corresponding values derived from the UNSCEAR (1969) global pattern are 300 Bq m(-2) and 600 Bq m(-2). High 137Cs inputs were found in high-rainfall areas in northern and central parts of the territory.