By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Th...By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.展开更多
In this work, we prepared three simple arylamine-based hole transporting materials from commercially available starting materials. The effect of extending z-conjugation length or increasing the number of side groups c...In this work, we prepared three simple arylamine-based hole transporting materials from commercially available starting materials. The effect of extending z-conjugation length or increasing the number of side groups compared with reference compound on the photophysical, electrochemical, hole mobility properties and performance in perovskite solar cells were further studied. It is noted that these two kinds of molecular modifications can significantly lower the HOMO level and improve the hole mobility, thus improving the hole injection from valence band of perovskite. On the other hand, the compound with more side groups showed higher hole injection efficiency due to lower HOMO level and higher hole mo- bility compared with the compound with extending π-conjugation length. The perovskite solar cells with the modified molecules as hole transporting materials showed a higher efficiency of 15.40% and 16.95%, respectively, which is better than that of the reference compound （13.18%）. Moreover, the compound with increasing number of side groups based devices showed comparable photovoltaic performance with that of conventional spiro-OMeTAD （16.87%）.展开更多
New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was e...New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was examined.For K+ ion transfer,preserving phenolic hydroxyl in the lower rim of calix[4]arene could enhance its transport ability.When benzoyl replaced phenolic hydroxyl,the transport would fall off,because benzoyl caused steric hindrance on the K+ transfer.The study also revealed that the group having the electron-withdrawing conjugative effect on phenolic hydroxyl,-NO2 in the upper rim of calix[4]arene,made transport ability of calix[4]arene fall off.On the contrary,-NH2 that had electron-repulsive conjugative effect enhanced the transport ability of the compound.For Hg2+ ion,only -NH2 in the upper rim of calix[4]arenes had high affinity for it and contributed to Hg2+ transfer.Transport amount of Hg2+ ion increased with increasing calix[4]arene5 concentration and ΔpH in BLM.展开更多
With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Ya...With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are modeled.Two numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order model.For these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.展开更多
基金financially supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.51125034)the National Natural Science Foundation of China(Grant Nos.51279046 and 50909037)the Fundamental Research Funds for the Central Universities(Grant No.2010B01114)
文摘By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.
基金supported by the National Basic Research Program of China (No. 2015CB932200)the CAS-Iranian Vice Presidency for Science and Technology Joint Research Project (No. 116134KYSB20160130)+2 种基金the Natural Science Foundation of Anhui Province (No. 1508085SMF224)the National Natural Science Foundation of China (No. 51474201)the External Cooperation Program of BIC, Chinese Academy of Sciences (No. GJHZ1607)
文摘In this work, we prepared three simple arylamine-based hole transporting materials from commercially available starting materials. The effect of extending z-conjugation length or increasing the number of side groups compared with reference compound on the photophysical, electrochemical, hole mobility properties and performance in perovskite solar cells were further studied. It is noted that these two kinds of molecular modifications can significantly lower the HOMO level and improve the hole mobility, thus improving the hole injection from valence band of perovskite. On the other hand, the compound with more side groups showed higher hole injection efficiency due to lower HOMO level and higher hole mo- bility compared with the compound with extending π-conjugation length. The perovskite solar cells with the modified molecules as hole transporting materials showed a higher efficiency of 15.40% and 16.95%, respectively, which is better than that of the reference compound （13.18%）. Moreover, the compound with increasing number of side groups based devices showed comparable photovoltaic performance with that of conventional spiro-OMeTAD （16.87%）.
基金Natural Science Foundation of Education Department of Anhui Province,China(No. KJ2011B021)
文摘New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was examined.For K+ ion transfer,preserving phenolic hydroxyl in the lower rim of calix[4]arene could enhance its transport ability.When benzoyl replaced phenolic hydroxyl,the transport would fall off,because benzoyl caused steric hindrance on the K+ transfer.The study also revealed that the group having the electron-withdrawing conjugative effect on phenolic hydroxyl,-NO2 in the upper rim of calix[4]arene,made transport ability of calix[4]arene fall off.On the contrary,-NH2 that had electron-repulsive conjugative effect enhanced the transport ability of the compound.For Hg2+ ion,only -NH2 in the upper rim of calix[4]arenes had high affinity for it and contributed to Hg2+ transfer.Transport amount of Hg2+ ion increased with increasing calix[4]arene5 concentration and ΔpH in BLM.
基金supported by the National Natural Science Foundation of China (10872192)
文摘With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are modeled.Two numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order model.For these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.
