最小生成树法在环境背景值识别中的应用

本文用最小生成树法解决环境中的聚类分析问题。该法用x~2距离系数矩阵描述样本变量间的相似关系,同时用Kruskal法构造最小生成树,最后以分类图的形式给出分类结果。     

A2/O+硫磺填料柱组合工艺脱氮除磷的效果

以某城市污水厂进水为研究对象,采用A2/O+硫磺填料反应柱组合工艺,考察其对COD、总氮、总磷以及溶解性磷处理效果的改善。组合工艺出水水质稳定后,连续运行55 d,并对工艺的出水进行常规指标分析。结果表明:组合工艺的脱氮除磷效果较单个A2/O工艺都得到了较大的改善,而COD去除效果变化不大。A2/O系统对COD有良好的去除效果,出水的COD平均去除率能达到94%;TN和TP去除效果相对较差,出水平均去除率分别为60%和57.4%。经硫磺填料反应柱的脱氮除磷作用,系统出水TN去除率提高到84%,TP去除率提高到69.8%,COD去除率变化不大,升高到95.3%。     

Transcriptional profiles induced by the Aryl Hydrocarbon Receptor agonists 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,7,8-pentachlorodibenzofuran in primary rat hepatocytes

Toxicogenomics was used to examine mRNA expression profiles obtained from primary rat hepatocytes treated for 24 h with 0.01 or 1.0 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 0.02 or 2.0 nM 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF) and 0.1 or 10 nM 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF). The concentrations of 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF were chosen to be equivalent to 2,3,7,8-TCDD’s concentration based on the toxic equivalency factor/toxic equivalent (TEF/TEQ) method for estimating biological potency. 2,3,7,8-TCDD at 1.0 nM altered the expression of 533 genes; 2,3,4,7,8-PeCDF at 2.0 nM altered 182 genes, and 2,3,7,8-TCDF at 10 nM altered 154 genes. Of these, 57 genes were affected by all three congeners. Agglomerative hierarchical clustering revealed distinct congener-dependent gene subclusters. Principal components analyses of the microarray data revealed that these congeners cluster independently of one another. Data presented here demonstrate that equivalent TEQ concentrations of 2,3,7,8-TCDD, 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF, while altering the expression of a small battery of genes in common, also produce substantial congener specific alterations in gene expression.     

基于HJ 1A/1B卫星遥感数据的积雪识别方法研究

积雪分布与变化是标示气候变化的敏感因子,采用具有长时间序列的大范围同步获取信息优势的卫星遥感数据进行积雪识别提取,具有重要的理论意义和实际应用价值。针对HJ 1A/1B卫星数据,结合积雪遥感监测的理论方法,在分析HJ 1A/1B卫星CCD和IRS传感器光谱响应特征的基础上,将应用较广的归一化差分积雪指数(NDSI)引入到HJ 1A/1B卫星中,得到了基于CCD和IRS两个传感器数据的HJ NDSI积雪识别方法。为避免由幅宽、扫描区域等因素的差异引起的两种不同传感器同时相数据难获取的问题,对HJ NDSI方法进行了改进,提出了一种仅利用IRS传感器数据的HJ MNDSI积雪识别方法。通过对HJ卫星数据的统计分析,给出了两种方法中的推荐阈值。以西藏普兰为实验区,对上述两种方法得到的结果进行精度评价,结果表明,HJ NDSI和HJ MNDSI方法提取积雪的精度分别为97.66%和94.92%,均能满足实际应用的需要,但HJ MNDSI方法能保证更大的积雪监测范围。     

校园再生水回用工程设计

采用A2/O及深度处理工艺处理校园生活污水,再生水回用于校园人工湖补水和杂用。工程造价少,运行费低,运行出水同时达到景观用水和杂用水水质标准。     

A2O工艺好氧末段溶解氧变化对脱氮除磷影响

采用连续流A2O工艺处理实际的生活污水,研究好氧末段在不同溶解氧（DO）浓度条件下对污泥沉降性能、系统脱氮除磷的影响,同时考察了DO对污泥硝化活性、厌氧释磷速率和反硝化脱氮速率的影响。结果表明,随着末段溶解氧的提高,污泥容积指数SVI从140降至100左右,后又升高到120~170;系统的硝化效果提高,氨氮的去除率从60%升高到80%以上再到90%以上;总氮的去除效果也有显著提高,平均去除率从54%升高到63%再到67%;虽然磷的去除效果有所加强,总磷的平均去除率从41%升高到59%再到69%,但仍难达标。     

A/A/O工艺脱氮除磷运行效果分析

为提高城市污水处理厂科学运行管理水平和出水质量,通过对某污水处理厂污水处理工艺的沿程采样分析,对比分析了A/A/O工艺脱氮除磷效果与工艺运行控制参数之间的相关关系。结果表明,A/A/O工艺对总氮去除率为83.2%,出水中氮的形态主要为硝酸盐氮;出水中总磷浓度基本达到一级A标准,总磷去除率在86.3%以上;缺氧段具有明显...     

Bisphenol A and Bisphenol S release in milk under household conditions from baby bottles marketed in Italy

A simple and sensitive validated analytical method based on liquid chromatography coupled to tandem fluorescence (FD) and ultraviolet (UV) spectrophotometry was applied to monitor the presence of bisphenol A and bisphenol S in plastic baby bottles marketed in Italy. The limits of detection (LOD) were 3.75 ng mL^?1 and 80.00 ng mL^?1, and those of quantification (LOQ) were 12.51 ng mL^?1 and 260.00 ng mL^?1 for BPA (FD detection) and for BPS (UV detection), respectively. BPA was found in only four samples, two samples undergone to microwave heating and two samples undergone to bottle warmer heating either at 40°C or at 80°C. Although the quantities of leached BPA were well below the reference dose for daily intake established by the European Food Safety Authority (EFSA) (4.0 µg kg^?1 bw/day), the release of BPA and BPS from these plastic materials should be carefully considered by the government authorities to increase people's awareness on this issue and to protect the most vulnerable population group.     

基于欧洲航天局“哨兵-2A”卫星的太湖蓝藻遥感监测

欧洲航天局(ESA)2015年6月23日成功发射"哨兵-2A"卫星,该卫星搭载的多光谱成像仪(MSI)在可见光(VIS)至短波红外(SWIR)波长区间配置了多种光谱波段/地面分辨率组合,可以获取大范围、较短重访周期、较高空间分辨率(10 m)的遥感影像。以太湖2016年6月13日MSI数据为例,在完成大气校正的基础上,分析了太湖典型地物类型光谱特征,采用归一化植被指数(NDVI)结合叶绿素反射峰强度(ρchl)构建的综合阈值法对贡湖湾的蓝藻水华信息进行了提取实验。结果表明:"哨兵-2A"卫星MSI影像质量清晰,可精细地反映植被、蓝藻、水体等典型地物类型的光谱特征;ρchl指数对中-高蓝藻聚集区与水生植被、轻度蓝藻聚集区与混合水体具有较好的分离能力;利用综合阈值法提取贡湖湾中-高蓝藻聚集区面积为60.37 km2,主要分布在贡湖北部沿岸、湖心和南部沿岸。"藻-水"混悬体面积为79.49 km2,贡湖湾东部蓝藻水华相对较轻。     

液液萃取—GC-MS法同时测定石化废水中双酚A和邻苯二甲酸二乙酯

建立了液液萃取（LLE）—气相色谱-质谱（GC-MS）法同时测定石化废水中双酚A（BPA）和邻苯二甲酸二乙酯（DEP）的新方法,对液液萃取条件进行了优化。最佳的液液萃取条件为：萃取剂为乙酸乙酯,水样调成酸性（pH<2）,每次加入萃取剂0.1 mL/mL、盐析剂NaCl 0.1 g/mL,萃取次数为6次,每次萃取时间为2 min。实验结果表明：在质量浓度1~100 mg/L的范围内,BPA和DEP测定标准曲线的线性关系良好;BPA和DEP的检出限（LOD）分别为5.18 μg/L和0.89 μg/L,定量限（LOQ）分别为17.11 μg/L和2.96 μg/L,回收率为81.4 %~124.9 %,相对标准偏差（RSD）（n=7）小于5.5 %。