Pollutants release is highly consistent with suspended sediment concentration （SSC） in water column, especially during re-suspension and transport events. The present research focuses on pollutant dynamic release fr...Pollutants release is highly consistent with suspended sediment concentration （SSC） in water column, especially during re-suspension and transport events. The present research focuses on pollutant dynamic release from re-suspended sediment, especially the vertical distribution relationship between them. The sediment erosion experiments on a series of uniform flow are conducted in a circulate flume. Reactive tracer （phosphorus） is used as the contaminant in fine-grained sediments to identify the release characteristic length and time. Experimental results show that the flow condition near-bed depends on the sediment surface roughness. The region with high turbulent intensities corresponds to a high concentration sediment layer. In addition, the SSC decreases with the distance, water depth, and particle grain size. The sediment in a smaller grain size takes much more time to reach equilibrium concentration. Total phosphorus （TP） concentration changes along the water depth as SSC in the initial re-suspension stage, appearing in two obvious concentration regimes： the upper low-concentration layer and the high-concentration near-bottom layer. This layered phenomenon remains for about 3 hours until SSC distri- bution tends to be uniform. Longitudinal desorption plays an important role in long-way transport to reduce the amount of suspended sediment in water column.展开更多
The Ni_81Fe_19 / Ta films with different NiFe thickness were prepared atdifferent base vacuums and sputtering pressures. The results of magnetic measurement and atomicforce microscope (AFM) showed that the films prepa...The Ni_81Fe_19 / Ta films with different NiFe thickness were prepared atdifferent base vacuums and sputtering pressures. The results of magnetic measurement and atomicforce microscope (AFM) showed that the films prepared at higher base vacuum and lower sputteringpressure had larger DELTAR/R. The reason should be that higher base vacuum and lower sputteringpressure introduce larger grainsize and lower surface roughness, which will weaken the scattering ofelectrons, reduce the resistance R, and increase DELTAR/R.展开更多
基金Project supported by the National Natural Science Foundation of China(No.10972134)the National Key Program of National Natural Science Foundation of China(No.11032007)the Shanghai Program for Innovative Research Team in Universities
文摘Pollutants release is highly consistent with suspended sediment concentration （SSC） in water column, especially during re-suspension and transport events. The present research focuses on pollutant dynamic release from re-suspended sediment, especially the vertical distribution relationship between them. The sediment erosion experiments on a series of uniform flow are conducted in a circulate flume. Reactive tracer （phosphorus） is used as the contaminant in fine-grained sediments to identify the release characteristic length and time. Experimental results show that the flow condition near-bed depends on the sediment surface roughness. The region with high turbulent intensities corresponds to a high concentration sediment layer. In addition, the SSC decreases with the distance, water depth, and particle grain size. The sediment in a smaller grain size takes much more time to reach equilibrium concentration. Total phosphorus （TP） concentration changes along the water depth as SSC in the initial re-suspension stage, appearing in two obvious concentration regimes： the upper low-concentration layer and the high-concentration near-bottom layer. This layered phenomenon remains for about 3 hours until SSC distri- bution tends to be uniform. Longitudinal desorption plays an important role in long-way transport to reduce the amount of suspended sediment in water column.
基金This work was financially supported by the Nationl Science Foundation of China under the contract No. 19890310.
文摘The Ni_81Fe_19 / Ta films with different NiFe thickness were prepared atdifferent base vacuums and sputtering pressures. The results of magnetic measurement and atomicforce microscope (AFM) showed that the films prepared at higher base vacuum and lower sputteringpressure had larger DELTAR/R. The reason should be that higher base vacuum and lower sputteringpressure introduce larger grainsize and lower surface roughness, which will weaken the scattering ofelectrons, reduce the resistance R, and increase DELTAR/R.
