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为明确凋落物混用对修复油污土壤效果的影响,以含石油质量分数15 g/kg的污染土壤为研究对象,分别加入质量分数2%的单种凋落物(胡枝子、铁杆蒿、黄蒿的凋落物)及3种凋落物的混合物(质量比为1∶1∶1),在室温(20~25 ℃)、恒湿(饱和水质量分数50%)的条件下进行150 d的修复模拟实验。基于单种凋落物的处理结果及其在混合物中所占比例,计算混合物处理后污染物降解率以及土壤生化指标的理论预测值,并与实测值进行比较,以研究凋落物混用对土壤石油污染修复效果的影响。结果表明:凋落物混用强化了凋落物对土壤石油污染物的降解效果,使石油降解率比对应预测值提高了12.16%,其中饱和烃、芳香烃和非烃物质的降解率比对应预测值分别提高了14.43%、9.24%和10.52%;凋落物混用强化了凋落物对土壤漆酶和过氧化氢酶活性的刺激作用,但同时削弱了其对木质素过氧化物酶、蔗糖酶和多酚氧化酶活性的刺激作用,对土壤硝态氮的补充效果以及对土壤的酸化效应。 相似文献
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This paper presents the simulation and the analysis of the transient process of a Francis turbine during the load rejection by employing a one-dimensional and three-dimensional (1-D-3-D) coupling approach. The coupling is realized by partly overlapping the I-D and 3-D parts, the water hammer wave is modeled by defining the pressure dependent density, and the guide vane closure is treated by a dynamic mesh method. To verify the results of the coupling approach, the transient parameters for both typical models and a real power station are compared with the data obtained by the 1-D approach, and good agreements are found. To investigate the differences between the transient and steady states at the corresponding operating parameters, the flow characteristics inside a turbine of the real power station are simulated by both transient and steady methods, and the results are analyzed in details. Our analysis suggests that there are just a little differences in the turbine outer characteristics, thus the traditional 1-D method is in general acceptable. However, the flow patterns in the spiral casing, the draft tube, and the runner passages are quite different: the transient situation has obvious water hammer waves, the water inertia, and some other effects. These may be crucial for the draft tube pul- sation and need further studies. 相似文献
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城市地下综合管廊纵向接头对于管廊整体稳定与正常使用有着重要影响,近年来随着我国基础设施建设的不断完善与加强,综合管廊的结构与形式随之更新发展,其中以预制拼装综合管廊为主。为分析该类管廊接头的抗弯性能以及接头变形情况,以平潭某综合管廊工程为背景,采用ABAQUS软件并通过三维有限元法对预制预应力综合管廊的接头受力情况进行分析,研究管廊接头在竖向荷载作用下的破坏过程,通过对预应力钢筋与普通钢筋的应变、接头变形情况、荷载与挠度的变化关系以及接头抗弯刚度等方面的分析,分析结果可以作为管廊的设计与实际应用的参考。 相似文献
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本文从简述现代主义入手,进而介绍现代主义建筑的发展历程和现今特点,指出现代主义在中国并没有消亡,而是继续发展。由此认为现代主义在中国的发展具有可能性和必然性,而后通过介绍东方的审美和美学思想,指出现代主义与东方精神的融合不是简单的东西混合,而是理解领悟东西方文化、创造蕴含东方精神、符合现代主义理念的本土建筑。要在理念上、形式上、技术上积极继承和创新,以达到现代主义与东方精神的真正融合。 相似文献
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