Spatial variability of bacteria in the rhizosphere of Elsholtzia splendens under Cu contamination

Elsholtzia splendens is a well-known Cu-tolerant plant; yet, the impact of Cu-contaminated soil on bacterial community in its rhizosphere is not known. We studied the spatial variability of bacteria in the rhizosphere using Cu-contaminated soil with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and real-time PCR. In the uncontaminated soil, the content of the dissolved organic carbon (DOC) and bacterial diversity gradually increased in the rhizosphere soil along the root growth direction (from the interface zone to the meristematic zone), while for the Cu-contaminated soil, the highest DOC content and the strongest potential bioavailability of Cu were found in the interface zone, which also had the lowest bacteria diversity. Bacteria diversity was positively correlated with DOC in the uncontaminated soil (p?Firmicutes only existed in the rhizosphere of contaminated soil, while the very small amount (if any) of some species exists such as Deinococcus-Thermus, indicating that the contaminated environment altered the bacterial composition. Moreover, spatial variation of the bacterial community was found among different soil zones. Real-time PCR confirmed the spatial variation via the gene expression of flagellin (fliC) and chemotaxis gene (cheA). The spatial characteristics of cheA expression were consistent with that of DOC and bacterial diversity. In conclusion, we demonstrated that the spatial variation of the bacterial community in the rhizosphere was present, independent of Cu contamination. DOC and Cu toxicity may affect specific gene expressions such as fliC and cheA, resulting in bacterial spatial variation.     

任意变截面棒材无模拉伸数学模型的研究

无模拉伸是近年来新开发的一种金属成形工艺。此文在对无模拉伸的发展动态、国内外研究概况等进行综合分析的基础上,分析了任意变截面棒材无模拉伸的变形机制及成形可行性,提出了任意变截面棒材无模拉伸速度或冷热源移动速度的理论计算方法。并提出了几种抛物面棒材无模拉伸的速度模型。经过实验研究证明,此文提出的速度模型较好地表达了任意变截面棒材无模拉伸速度变化规律。     

水解聚合铝溶液中形态分布的定量模拟研究

通过Ａｌ－Ｆｅｒｒｏｎ逐时络合比色法和￣（２７）Ａｌ核磁共振（ＮＭＲ）法，并应用“ＭＩＮＥＱＬ”化学平衡模式计算法，对采用不同反应途径制得的聚合铝（ＰＡＣ）溶液中的化学形态分布规律进行了定量模拟研究和对比。模式计算结果与两种实验定量分析结果都较为吻合，结果表明，在水解聚合铝溶液中较稳定的化学形态主要有五种：一种单体形态［ａｌ＿ａ］，即Ａｌ￣（３＋），Ａｌ（ＯＨ）￣（２＋），Ａｌ（ＯＨ）＿２￣＋；３种聚合形态［Ａｌ＿ｂ］，即和以及一种溶胶或凝胶形态［Ａｌ＿ｃ］，即Ａｌ（ＯＨ）＿３（ａｍ）．这些化学形态的分布和转化不仅取决于溶液的化学特征，而且也取决于制备方法的不同。     

混凝过程中铝与聚合铝水解形态的动力学转化及其稳定性

采用Ｆｅｒｒｏｎ逐时络合比色法，并结合电泳测定研究了混凝过程中氯化铝和聚合氯化铝的水解形态动力学转化及稳定性。结果表明，ＡＣ在混凝过程中所形成的水解形态完全不同于ＰＡＣ的预制水解聚合形态，其电荷及分子量均明显低于聚合铝且不稳定，ＡＣ随混凝条件如投加浓度、ＰＨ和混合时间而变，而ＰＡＣ－２５水解聚合形态不随混凝条件变化，始终保持稳定状态，ＡＣ水解沉淀规律与理论计算相符并形成无定形Ａｌ（ＯＨ）３絮体颗粒     

环境质量与经济增长的库兹尼茨关系探讨

对环境质量与经济增长的库兹尼茨关系进行了分析，提出了环境质量三种可能的发展轨迹，并探讨了在这三种可能发的发展轨迹中，经济增长对环境质量发展的影响，提出了中国现阶在保证环境质量达一害标准的前提下，实现经济可持 展的政策建议。     

Assessment of the environmental impact of artificial effluent lagoon in Jiayuguan City of China

An artificial effluent lagoon for storing wastewater were excavated in Jiayuguan City since 1994. As a part of a demonstration project of Sino-Austmlia cooperation, an assessment of the environmental impact of the lagoon was carried out. The assessment was based on field and laboratory tests and predictive model. The main impacts from the lagoon site are likely to be on the groundwater system, and, to a lesser extent,on ambient air quality in the vicinity. Currently it is expected that groundwater is being pollutod with effluent from the effluent Ingcen. Air pollution(odor nuisance) is mainly caused by untreated effluent in the irrigation channel. The impact of high total dissolved salt(TDS) on groundwater is likely to be significant in the long run if the lagoon is continuously used. There is, consequently, no likelihood of contamination of surface water system, particularly of the city water supply system, from infiltration of effluent at the lagoon.     

Adsorption characteristics of copper in rivers contaminated by acid mine drainage from copper mine

Ａｄｓｏｒｐｔｉｏｎｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｃｏｐｐｅｒｉｎｒｉｖｅｒｓｃｏｎｔａｍｉｎａｔｅｄｂｙａｃｉｄｍｉｎｅｄｒａｉｎａｇｅｆｒｏｍｃｏｐｐｅｒｍｉｎｅ￥ＬｕａｎＺｈａｏｋｕｎ；ＣｈｅｎＭｉｎｇ；ＴａｎｇＨｏｎｇｘｉａｏ（Ｒｅｓｅａ...     

甘肃省悬钩子属植物资源分布及其开发前景初探

悬钩子属植物在甘肃共有３４种、８变种，分布于南秦岭山地、北秦岭山地森林、甘南山地森林、东祁连山林区、陇西、陇东黄土高原区及甘南高山草原区。大多数具可食性，具开发利用价值。建立悬钩子的栽培试验基地是保证原料供应的重要措施。通过对悬钩子产品的市场需求量及产品属类的评估，可望将其潜在的野生价值转变为实际生产力。     

电解预处理-UASB-CASS工艺处理糠醛废水

对电解预处理-UASB-CASS工艺处理糠醛废水进行了研究,通过试验确定了电解预处理阶段主要影响因素为电流强度大小和电解时间,极板间距对COD去除率影响不大;电解预处理最佳工艺参数为:电流强度0.3 A,电解时间4 h,极板间距30 mm.在此条件下COD去除率为20.6%,废水可生化性提高了38.1%.加上后续的UASB-CASS工艺,出水COD浓度＜150 mg/L,满足《污水综合排放标准》(GB8978-1996)二级排放标准.     

聚合氯化铝絮凝剂深度除磷实验研究

通过混凝实验考察了聚合氯化铝絮凝剂(PAC)除磷作用,研究探讨了聚二甲基二烯丙基氯化铵(PDADMAC),赤泥与聚合氯化铝的协同除磷性能.研究表明,PAC具有良好的除磷效果,对模拟废水磷的去除率达94.6%,对实际污水总磷去除率达96.6%,浊度去除率达93.8%.赤泥能显著提高PAC的除磷效果,但PDADMAC没有明显作用.