为探究当前环境流量的研究进展及发展方向,补充环境流量评估方面的研究方法,概述了国内外环境流量研究进展,应用CiteSpace软件结合中国知网与Web of Science数据库分析环境流量研究方法在21世纪以来的历史热点及主题演变情况。从开发背...为探究当前环境流量的研究进展及发展方向,补充环境流量评估方面的研究方法,概述了国内外环境流量研究进展,应用CiteSpace软件结合中国知网与Web of Science数据库分析环境流量研究方法在21世纪以来的历史热点及主题演变情况。从开发背景、模型模块及应用步骤等方面详细介绍了一种用于环境流量评估的整体法——下游河道对流量变化响应法DRIFT(Downstream Response to Imposed Flow Transformation),结合南非奥卡万戈河以及赞比西河工程案例总结了该方法在环境流量评估及生态系统保护研究方面的应用,为环境流量研究提供新的思路与方法。展开更多
A highly active photocatalyst CeO2/NaNbO3 is fabricated by a simple and facile hydrothermal method.The obtained photocatalyst composites are characterized by X‐ray powder diffraction,scanning electron microscopy,tran...A highly active photocatalyst CeO2/NaNbO3 is fabricated by a simple and facile hydrothermal method.The obtained photocatalyst composites are characterized by X‐ray powder diffraction,scanning electron microscopy,transmission electron microscopy and ultraviolet‐visible diffuse reflectance spectroscopy.The photocatalytic activity of the obtained samples is demonstrated by the photocatalytic degradation of the colorless antibiotic agent ciprofloxacin and the dye rhodamine B.The results reveal that CeO2/NaNbO3 composites exhibit a higher photocatalytic property than pure NaNbO3 under both UV and visible light irradiation.Furthermore,the optimum mass ratio of CeO2 in the CeO2/NaNbO3 composites is 2.0 wt%.The improved photocatalytic activity is attributed to the higher separation rate of the photo‐induced electrons and holes,and the higher migration rate of the photogenerated charge in the interfacial region.Furthermore,the photoluminescence pectra,photocurrent,electrochemical impedance spectroscopy and trapping experiment are applied to demonstrate the photocatalytic reaction mechanism of the as‐prepared samples.The result of the trapping experiment indicates that?OH radicals,?O2– radicals and holes are all involved in the photocatalytic degradation process of RhB.Furthermore,a possible mechanism for the enhancement of the photocatalytic activity is also proposed.展开更多
The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating...The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities（ v= 0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s）, floating bed coverage rates（20%, 40%, 60%） and arrangement positions away from the channel wall（ D= 0 m, 0.1 m, 0.2 m）. The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value（ARWLV） increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition（v ？0.2 m /s）.展开更多
文摘为探究当前环境流量的研究进展及发展方向,补充环境流量评估方面的研究方法,概述了国内外环境流量研究进展,应用CiteSpace软件结合中国知网与Web of Science数据库分析环境流量研究方法在21世纪以来的历史热点及主题演变情况。从开发背景、模型模块及应用步骤等方面详细介绍了一种用于环境流量评估的整体法——下游河道对流量变化响应法DRIFT(Downstream Response to Imposed Flow Transformation),结合南非奥卡万戈河以及赞比西河工程案例总结了该方法在环境流量评估及生态系统保护研究方面的应用,为环境流量研究提供新的思路与方法。
基金supported by the National Science Funds for Creative Research Groups of China(51421006)the National Science Fundation of China for Excellent Young Scholars(51422902)+3 种基金the Key Program of National Natural Science Foundation of China(41430751)the National Natural Science Foundation of China(51679063)the National Key Plan for Research and Development of China(2016YFC0502203)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)~~
文摘A highly active photocatalyst CeO2/NaNbO3 is fabricated by a simple and facile hydrothermal method.The obtained photocatalyst composites are characterized by X‐ray powder diffraction,scanning electron microscopy,transmission electron microscopy and ultraviolet‐visible diffuse reflectance spectroscopy.The photocatalytic activity of the obtained samples is demonstrated by the photocatalytic degradation of the colorless antibiotic agent ciprofloxacin and the dye rhodamine B.The results reveal that CeO2/NaNbO3 composites exhibit a higher photocatalytic property than pure NaNbO3 under both UV and visible light irradiation.Furthermore,the optimum mass ratio of CeO2 in the CeO2/NaNbO3 composites is 2.0 wt%.The improved photocatalytic activity is attributed to the higher separation rate of the photo‐induced electrons and holes,and the higher migration rate of the photogenerated charge in the interfacial region.Furthermore,the photoluminescence pectra,photocurrent,electrochemical impedance spectroscopy and trapping experiment are applied to demonstrate the photocatalytic reaction mechanism of the as‐prepared samples.The result of the trapping experiment indicates that?OH radicals,?O2– radicals and holes are all involved in the photocatalytic degradation process of RhB.Furthermore,a possible mechanism for the enhancement of the photocatalytic activity is also proposed.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(Grant No.2012ZX07101-008)the National Science Fund for Distinguished Young Scholars(Grant No.51225901)+1 种基金the Research Fund for Innovation Team of Ministry of Education(Grant No.IRT13061)the Jiangsu Province QingLan Project
文摘The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities（ v= 0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s）, floating bed coverage rates（20%, 40%, 60%） and arrangement positions away from the channel wall（ D= 0 m, 0.1 m, 0.2 m）. The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value（ARWLV） increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition（v ？0.2 m /s）.
