Response relationships between abrupt seasonal temperature changes/warming (cooling) hiatuses in China and their influencing factors

Environmental Science and Pollution Research - The mechanisms of abrupt seasonal temperature changes and warming (cooling) hiatuses remain unclear. Clarifying how they respond to various...     

Response of extracellular and intracellular alkaline phosphatase in Microcystis aeruginosa to organic phosphorus

Environmental Science and Pollution Research - Cyanobacterial blooms caused by Microcystis have become a menace to public health and water quality in the global freshwater ecosystem. Alkaline...     

染料废水的催化氧化处理

在内电解的基础上,对染料废水进行催化氧化处理,处理二,排放水质达到国家二级排放标准,催化体系的最佳工艺条件为搅拌时间约４０ｍｉｎ,Ｈ２Ｏ２的加入量为每ｍＬ废水０．００５ｍＬ,催化剂的用量为每ｍＬ废水０．００５ｇ,ＰＨ值２．５左右。     

横向滑坡作用下管道裂纹力学影响因素分析∗

地质灾害和管体缺陷是油气管道安全运行的两大风险,山体滑坡是长输油气管道常见的一种地质灾害,裂纹是管道运行中难以发现却时有发生的管体缺陷之一。当穿越滑坡区的管道遭遇管体裂纹时,多重载荷的作用可能导致管体裂纹加剧甚至断裂失效。基于极限分析设计准则,研究了相关因素对滑坡区管道轴向裂纹的影响,采用有限元法,分析了滑坡宽度、滑坡位移、裂纹位置、裂纹深度比、裂纹形状比以及管道内压对裂纹J积分的影响。结果表明:滑坡宽度越大,J积分越小,滑坡位移越大,J积分越大;裂纹处于12点位置时,其J积分值最大,即轴向裂纹垂直于滑坡面时最危险;裂纹深度比和管道内压的增加均会导致J积分最大值呈指数增加,而裂纹形状比的增加会导致J积分最大值呈线性减小,J积分均在裂纹最深处取得最大值;较大的裂纹深度比会导致裂纹沿深度方向的扩展速度远大于沿长度方向,而较大的裂纹形状比会导致裂纹沿长度方向的扩展速度高于沿深度方向。     

中国北方地区年降水与气温关系及其时空变异性

降水与气温之间的不同关系类型对植被、水资源、生态环境等有着不同的影响,全面揭示大范围多气候类型区关系类型及其时空变异性和影响成为重要研究内容.文章以范围较广、涵盖气候类型较多的中国北方地区为研究区,利用研究区及其周边的357个高密度气象站点1951—2016年年降水量、气温数据,采用中心聚类等方法,定性、定量揭示了中国...     

Variations of alkaline phosphatase activity and P fractions in sediments of a shallow Chinese eutrophic lake (Lake Taihu)

The distribution of alkaline phosphatase activity (APA) and P fractions in sediment cores and the relationship between them were studied in a shallow Chinese freshwater lake (Lake Taihu). Sediment cores were collected from four sites, characterized by different degrees of eutrophication in June 2004. Sediment P was fractionated into Fe/Al-P, Ca-P, organic P (OP), inorganic P (IP) and total P (TP). The former two species made the largest contribution to the sediment P pool. Results show that trophic status and hydrological conditions have great impact on the APA of the sediments. The order of the APA in sediments was conjectured to be: macrophyte dominated lake>transitional lake>algal dominated lake. APA profiles follow a similar downcore decreasing trend. There was a positive relationship between the APA and the TP, IP. The multiple linear regression equation of the APA and P fractions is: APA=-97+0.768TP-0.985Fe/Al-P.     

双兰线管道水工保护结构分析及优化*

以双兰线沿线河流水毁冲刷情况为工程背景,在分析水毁成因机理和现场数据基础上,利用CFD数值模拟等手段,对应急性水工保护结构——石笼展开优化设计,设计3种不同形状的石笼并完成几何建模,在Fluent中利用VOF模型计算分析它们在淹没水域中的抗冲刷表现,从水流速度、石笼表面压力分布、水流阻力、床面剪切力这几个方面进行评价,以找出抗冲刷效果最好的石笼形状。最后完成水工保护结构的优化并针对不同结构进行适宜性分析。     

Simulated wetland conservation-restoration effects on water quantity and quality at watershed scale

Wetlands are one of the most important watershed microtopographic features that affect hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models such as the Soil and Water Assessment Tool (SWAT), enhanced by the hydrologic equivalent wetland (HEW) concept developed by Wang [Wang, X., Yang, W., Melesse, A.M., 2008. Using hydrologic equivalent wetland concept within SWAT to estimate streamflow in watersheds with numerous wetlands. Trans. ASABE 51 (1), 55–72.], can be a best resort. However, there is a serious lack of information about simulated effects using this kind of integrated modeling approach. The objective of this study was to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota. The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes and wetland characteristics (e.g., size and morphology) to be accurately represented in the models. The loss of the first 10–20% of the wetlands in the Minnesota study area would drastically increase the peak discharge and loadings of sediment, total phosphorus (TP), and total nitrogen (TN). On the other hand, the justifiable reductions of the peak discharge and loadings of sediment, TP, and TN in the Manitoba study area may require that 50–80% of the lost wetlands be restored. Further, the comparison between the predicted restoration and conservation effects revealed that wetland conservation seems to deserve a higher priority while both wetland conservation and restoration may be equally important.     

ET值及在美国超级基金项目中的应用

系统介绍了生态毒性阈值ＥＴ的定义，计算方法，在美国超级基金项目的生态风险评价中的应用及应用过程中的注意事项，并简要介绍了由美国环境保护局组织开发的ＥＴ值计算软件的安装及使用，该软件可以通过互联网名费得到。