松花坝水源区水窖对坡耕地地表径流及N、P输出的控制效果

通过3年的野外定点监测,研究昆明松花坝水源区微区域集水系统对坡耕地地表径流集蓄及径流面源污染物输出的控制效果,结果表明:一座容量为20 m3的水窖可集蓄坡度5°～25°、水平面积128～556 m2的产流量,集水区面积随坡度增大或作物覆盖度减小而相应减小;雨季,水窖每蓄水1 m3可同时蓄积总氮、硝态氮、铵态氮、总磷、磷酸盐分别达到0.38～1.60、0.26～0.92、0.03～0.31、0.04～0.13、0.02～0.06 g,有效减少了N、P随径流的输出量;旱季,随着水窖蓄水量减少,总氮、硝态氮、铵态氮浓度增大,而到次年雨季,其浓度值又会急剧降低。     

中国长江口潮滩湿地土壤重金属含量的时空变化规律及环境指示意义

The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chongming Island (EC) and the Jiuduansha Shoal (JS) of the estuary were selected as the study sites. At each of the two sites, a cross-transect from land to sea was established and topsoil and soil core samples in the cross-transect were collected spatially and seasonally to determine their contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Mn, and Fe) and grain-size characteristics. The results showed that the heavy metal loads were commonly higher in the soils of nearshore high tidal flats and had a tendency of decreasing from land to sea at both of the study sites. The contents of heavy metals in the soils of the high and medial tidal flats were mostly higher in April and November but lower in July. Corresponding spatial and seasonal variations in grain size of the intertidal soils were also observed at the two study sites. The soils in the nearshore high tidal flats were finer and gradually got coarser seawards; they were relatively finer in April and November but coarser in July. Furthermore, the contents of heavy metals in the intertidal soils of both the sites EC and JS were significantly positively correlated with the clay (<2 μm) and 2-20 μm fractions, but negatively with the sand (>63 μm) and 20-63 μm fractions, which suggested that the heavy metals in the intertidal soils were primarily combined with the fine particulate fraction (<20 μm), especially clay, and hence the spatial and seasonal variations in heavy metals were actually caused by the change of the grain-size characteristics of the intertidal soils due to the different sedimentary environments in the estuary. The results of this study may also contribute to a better understanding of the soil formation and classification in the tidal flats of the Yangtze Estuary.     

离心泵浮动叶轮轴向间隙的液体流动分析及轴向力计算

为了研究浮动叶轮轴向间隙变化对其液体泄漏量及压力、液体作用在不锈钢盘上轴向力的影响规律,将径向和轴向的间隙液体流动分别简化为平行平板间粘性层流运动和轴对称二维粘性层流运动,基于液体通过径向和轴向的间隙泄漏量相等,推导出了计算轴向间隙的液体泄漏量及压力、液体作用在不锈钢盘上轴向力的数学表达式。并通过设计实例计算,绘制出了轴向间隙的液体泄漏量和液体作用在不锈钢盘上轴向力与轴向间隙变化的关系曲线,从控制一定泄漏量并减少轴向力的角度出发,分析得出轴向间隙取0.4～0.8mm较为适宜。并在平衡腔内不安装不锈钢盘和石墨盘条件下,计算出了平衡腔内液体作用在叶轮上轴向力。通过比较分析,浮动叶轮有明显减少轴向力的效果。     

The harmonic Norton model established conditions of nonlinear load in low voltage distribution system

According to the experiments which concern about nonlinear loads in low voltage distribution systems,the voltage crest factor has a crucial effect on the establishment of nonlinear load harmonic Norton model,and it is verified by a large number of measured data. In the low voltage system that voltage waveform presents a flat characteristic,the nonlinear load can be simplified by the Norton model. Experimental and simulation results also show that different reference voltages can lead to different mean values of Norton model parameter which is obtained by fluctuation quantity method. The differences don’t have any effect on harmonic load flow analysis,but it affects the accuracy and credibility of the assessment load harmonic contribution level.     

Fenton法处理天然气净化厂废水实验研究

指出了天然气净化厂废水采用Fenton试剂进行高级氧化处理。通过实验得到了不同H2O2和Fe2+浓度、反应时间、pH值等因素对废水COD去除效果的影响。由实验结果可以得出:当H2O2的投加量为600mmol/L,FeSO4·7H2O投加量170mmol/L,反应时间60min,pH值=3.5时,废水中的COD浓度从2280mg/L降解至46mg/L,去除率为98%,出水能够达到国家一级A排放标准的要求。     

奎河灌溉水体中微生物分布及与有机污染物的相关性研究

以奎河水体中微生物群落为研究对象,分析了其数量分布以及与有机污染物的相关性。结果表明：奎河徐州过境段水体中的微生物数量从上游地区（1号采样点）、中游地区（2号采样点）到下游地区（3号采样点）呈现先下降后升高的趋势;水体中的微生物数量与有机污染物含量关系密切,细菌总数、大肠菌群数与总氮显著正相关,且相关系数R分别为0.817、0.836;细菌总数、大肠菌群数、蛔虫卵数与COD显著正相关且R分别为0.821、0.838、0.949,大肠菌群数与悬浮固体（SS）显著正相关且R为0.737;细菌总数、大肠菌群数、蛔虫卵数与总磷、色度相关性不显著。     

我国复合污染土壤修复研究进展

重金属、有机污染物造成的土壤复合污染是我国亟待解决的环境问题之一。当前,我国对复合污染土壤修复的研究主要集中于单一的生物、物理、化学等修复方法,而对于不同修复方法联合修复复合污染土壤的研究较少。从土壤重金属复合污染修复、有机污染物复合污染修复、重金属-有机污染物复合污染修复三方面全面综述了我国复合污染土壤修复的研究进展,并在此基础上提出了复合污染土壤修复研究的发展方向。     

畜禽养殖废水在硝化反应器内的硝化性能研究

针对近年来中国规模化养殖场迅速发展所带来的严重环境污染,特别是畜禽养殖废水中氨氮污染物所产生的污染,采用硝化反应器对其进行处理。首先进行硝化细菌的培养驯化,然后通过连续运行试验、间歇运行试验,考察氨氮的去除效果和操作参数的影响。试验结果表明:当温度为25℃,pH为6～7,DO为4～6mg·L-1,HRT为12h,进水氨氮为200mg·L-1时,出水氨氮浓度可以降低到1mg·L-1左右,氨氮的去除率接近100%。     

时间迭代步长对单层网壳非线性动力分析的影响

在进行地震作用下网壳结构的非线性动力分析及动力稳定分析过程中,不同的计算时间迭代步长对网壳的动力响应有着很大的影响,进而影响到动力稳定临界荷载的判断。针对两个网壳实例就时间迭代步长对其非线性动力响应的影响进行分析比较,在兼顾计算精度及计算量的基础上,提出了针对此类结构非线性动力分析时间迭代步长的选取建议。     

黄河兰州段多环芳烃类有机污染物健康风险评价

近年来黄河兰州段的多环芳烃污染日渐严重。为研究黄河兰州段水体中多环芳烃类有机污染物对人体产生的潜在健康危害风险,根据黄河兰州段2004年11个采样点水质监测数据,应用美国环境保护局（USEPA）的健康风险评价方法对黄河兰州段多环芳烃类有机污染物通过饮水和皮肤接触途径进入人体的健康风险进行了初步评价。结果表明：黄河兰州段多环芳烃类有机污染物的非致癌风险指数值均小于1,其中萘的非致癌风险指数值在10^-3数量级,偏高于其他污染物。苯并（a）芘的致癌风险指数值在10^-4数量级以下。从位于西固八盘峡的1号采样点（S1）采集的水样中萘的非致癌风险指数值偏高。在所有采样点中,西固八盘峡的1号采样点（S1）污染较重,具有较高的健康风险。与国内其他地区相比,黄河兰州段萘的非致癌风险亦较高。常规的自来水处理工艺不能有效地去除源水中微量PAHs等有机污染物,因此地面水特别是饮用源水PAHs污染具有较大的健康风险。