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明渠凹槽泥沙回填过程的水沙两相相互作用 被引量:1
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作者 胡鹏 吕冰晗 +1 位作者 李季 曹志先 《泥沙研究》 CAS CSCD 北大核心 2022年第3期23-30,共8页
航道疏浚和河流挖沙引起的深槽及深坑的泥沙回淤是典型的水沙两相运动过程。以往针对深槽及深坑的泥沙回淤数值模拟多假定泥沙速度等于水流速度,忽略了水流和泥沙之间的相互作用。通过建立平面二维水沙两相数学模型,分别求解浑水和泥沙... 航道疏浚和河流挖沙引起的深槽及深坑的泥沙回淤是典型的水沙两相运动过程。以往针对深槽及深坑的泥沙回淤数值模拟多假定泥沙速度等于水流速度,忽略了水流和泥沙之间的相互作用。通过建立平面二维水沙两相数学模型,分别求解浑水和泥沙的守恒方程,并将该模型与传统拟单相流模型对比,复演了两个典型明渠凹槽的泥沙回填水槽实验。研究发现:在同等参数条件下,水沙两相流数学模型能更好地复演实测结果。分析水沙之间相互作用发现,泥沙主要受底床切应力、水沙之间相互作用力和颗粒间作用力的影响,其中,底床切应力阻碍泥沙运动,水沙之间相互作用力是泥沙运动的主要动力来源。 展开更多
关键词 水沙两相流 水沙相互作用 凹槽回淤 航道疏浚 河流挖沙
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泥石流入汇对河流河床演变的影响 被引量:14
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作者 梁志勇 刘峡 +1 位作者 徐永年 隋忠诚 《自然灾害学报》 CSCD 北大核心 2001年第1期45-50,共6页
通过对现有文献资料的总结,探讨了泥石流入汇后随主河水流运动的几种可能形态和运动特点,分析了主河河床的演变情况,并提出按主支流水沙相互作用的大小,将主河河床演变分为弯曲、摆动和急流-深潭3种类型;对不同类型河流河床演变... 通过对现有文献资料的总结,探讨了泥石流入汇后随主河水流运动的几种可能形态和运动特点,分析了主河河床的演变情况,并提出按主支流水沙相互作用的大小,将主河河床演变分为弯曲、摆动和急流-深潭3种类型;对不同类型河流河床演变进行了分析,为进行泥石流入汇对主河水流运动与河床演变影响的研究奠定了基础. 展开更多
关键词 泥石流 汇流区 河床演变 水沙相互作用
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Interaction between Cross-Linked Polyacrylamide and Water and Solute Flow in a Sand and Loam
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作者 Mesude ümran Oyman Seval Sütinal Sabit Ersahin 《Journal of Environmental Science and Engineering(A)》 2012年第9期1117-1121,共5页
Superabsorbents such as cross-linked PAM (polyacrylamides) are frequently used to increase water availability to plants. Commercial PAM providers suggest that besides its increasing water availability, PAMs also inc... Superabsorbents such as cross-linked PAM (polyacrylamides) are frequently used to increase water availability to plants. Commercial PAM providers suggest that besides its increasing water availability, PAMs also increase nutrient availability to plants. To test this premise, four application rates (0.0 g·kg^-1, 0.33 g·kg^-1, 1.66 g·kg^-1, 3.33 g·kg^-1 and 6.66 g·kg^-1) ofa PAM were mixed with sandy and loamy soils to evaluate its effect on nutrient leaching and retention in these soils. Miscible displacements of chloride were conducted on columns of PAM-soil mixtures and results were evaluated by an equilibrium CDE (convection dispersion equation) model. Increasing the PAM rates up to 1.66 g·kg^-1 resulted in increased early appearance and dispersive transport of chloride in sand. In addition, increasing the PAM rates gradually caused increased tailing of the breakthrough curves of chloride in both soils. These suggested that PAM increased preferential transport of chloride while it increased retention of chloride in soils. Effect of PAM on preferential transport and retardation of CI was greater in sand than loam. 展开更多
关键词 PAM equilibrium CDE model preferential flow miscible displacement breakthrough curve.
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Sorption of norfloxacin from aqueous solutions by activated carbon developed from Trapa natans husk 被引量:5
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作者 XIE HuiJun LIU WeiFeng +2 位作者 ZHANG Jian ZHANG ChengLu REN Liang 《Science China Chemistry》 SCIE EI CAS 2011年第5期835-843,共9页
The low-cost activated carbon was prepared from a renewable aquatic plant residue,Trapa natans husk,and tested for its ability to remove norfloxacin (NOR) from aqueous solutions. Physical and chemical properties of th... The low-cost activated carbon was prepared from a renewable aquatic plant residue,Trapa natans husk,and tested for its ability to remove norfloxacin (NOR) from aqueous solutions. Physical and chemical properties of the Trapa natans husk activated carbon (TAC) were characterized. TAC has a large surface area of 1274 m2/g and mesoporous structure. Carboxylic and hydroxyl groups contributed to the sorption of NOR onto TAC but they were not the most important factors in the sorption process. The rates of adsorption followed the pseudo-second-order kinetics and the overall rate of NOR uptake was controlled by both external mass transfer and intro particle diffusion during the entire adsorption period. The equilibrium data fitted well with the Freundlich and Tempkin models and the sorption was found to be a favorable process. The adsorption of NOR by TAC was strongly dependent on the solution pH. Electrostatic interaction and hydrophobic interaction were proposed to be the principal NOR sorption mechanism. 展开更多
关键词 NORFLOXACIN Trapa natans husk activated carbon adsorption kinetic and isotherms
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