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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. 相似文献
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A series of sphere-rod shape amphiphiles were designed and synthesized by connecting the rod-like oligofluorenes with different lengths(OF_n) to the different positions of the spherical [60]fullerene(C_(60)) through a rigid linkage. The conjugates were characterized by ~1H-NMR, ~(13)C-NMR, FTIR, EA and MALDI-TOF mass spectrometry. The optical and electronic properties of the conjugates were studied by UV-Vis absorption spectroscopy, fluorescence spectrometry, and cyclic voltammetry. The results from UV-Vis absorption spectroscopy and cyclic voltammetry indicated that the energy profiles of C_(60) and OF_n remained unchanged when different lengths of OF_n were attached to C_(60). The electron affinities of the OF_n-C_(60) conjugates were close to that of C_(60), while slight electronic interaction was found between the two individual chromophores(C_(60) and OF_n) in their ground states. The fluorescence spectra exhibited a complete fluorescence quenching in the toluene solution, suggesting an effective energy transfer from OF_n to C_(60). It presents a systematic study on the selfassembly, structure-property relationship, and potential technical applications of the conjugates. 相似文献
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Guomin Ai Jinxing Zhu Xiuzhu Dong Tong Sun 《Rapid communications in mass spectrometry : RCM》2013,27(17):1935-1944