Regioregular poly(1-butoxy-2,4-m-phenylenevinylene) was synthesized by Wittig reaction with salicylaldehyde as the starting material,and its properties were compared with poly(2,5-dibutoxy-1,4-p-phenylenevinylene-alte...Regioregular poly(1-butoxy-2,4-m-phenylenevinylene) was synthesized by Wittig reaction with salicylaldehyde as the starting material,and its properties were compared with poly(2,5-dibutoxy-1,4-p-phenylenevinylene-alter-p-phenylenevinylene) (Bu-PPV) and poly(2,5-dibutoxy-1,4-p-phenylenevinylene-alter-m-phenylenevinylene) (Bu-PMPV).The results showed that the introduction of m-phenylene could obviously improve the solubility.Thus,the solubility of Bu-PMPV was almost one order of magnitude higher than that of Bu-PPV,and Bu-MPV had a solubility 2～5 times of that of Bu-PMPV.The introduction of m-phenylene also caused obvious blue-shifts in the UV-Vis absorption and fluorescence spectra.The UV-Vis spectrum of Bu-MPV in CHCl 3 showed one absorption band λ max at 316、nm.The fluorescence of Bu-MPV solution in CHCl 3 exhibited a very narrow emission peak with emission maxima at about 419 and 434、nm,the full width at half-maximum of the emission peak is about 60、nm.展开更多
海草床是全球分布最广泛的滨海湿地生态系统,提供着重要的生态服务功能。但是近年来,在人类活动和气候变化的双重作用下,海草床不断退化。食物网是海草床生态系统的重要组成部分,研究食物网营养级之间的相互作用关系对于海草床的生物多...海草床是全球分布最广泛的滨海湿地生态系统,提供着重要的生态服务功能。但是近年来,在人类活动和气候变化的双重作用下,海草床不断退化。食物网是海草床生态系统的重要组成部分,研究食物网营养级之间的相互作用关系对于海草床的生物多样性和稳定性具有重要的意义。通过检索Web of Science和CNKI数据库中收录的海草床食物网营养级相互作用关系的相关文献,从研究区域、种类分布、营养级相互作用类型、环境影响因子以及研究方法等方面进行了文献分析,以期阐明国内外海草床食物网营养级研究相关进展。结果表明:目前的主要研究区域具有一定的地域性,以保护和恢复较好的区域为主;研究的海草种类主要为广泛分布的种类;研究的相互作用类型主要为食物网的部分环节,缺乏对整个营养级动态变化的研究;研究考虑的环境因子主要是富营养化的影响,而对于其他环境因子的动态变化涉及较少;目前的研究方法以模拟实验为主,多偏向于静态或者短期的模拟,缺乏对长期动态变化过程的模拟研究。展开更多
文摘Regioregular poly(1-butoxy-2,4-m-phenylenevinylene) was synthesized by Wittig reaction with salicylaldehyde as the starting material,and its properties were compared with poly(2,5-dibutoxy-1,4-p-phenylenevinylene-alter-p-phenylenevinylene) (Bu-PPV) and poly(2,5-dibutoxy-1,4-p-phenylenevinylene-alter-m-phenylenevinylene) (Bu-PMPV).The results showed that the introduction of m-phenylene could obviously improve the solubility.Thus,the solubility of Bu-PMPV was almost one order of magnitude higher than that of Bu-PPV,and Bu-MPV had a solubility 2～5 times of that of Bu-PMPV.The introduction of m-phenylene also caused obvious blue-shifts in the UV-Vis absorption and fluorescence spectra.The UV-Vis spectrum of Bu-MPV in CHCl 3 showed one absorption band λ max at 316、nm.The fluorescence of Bu-MPV solution in CHCl 3 exhibited a very narrow emission peak with emission maxima at about 419 and 434、nm,the full width at half-maximum of the emission peak is about 60、nm.
文摘海草床是全球分布最广泛的滨海湿地生态系统,提供着重要的生态服务功能。但是近年来,在人类活动和气候变化的双重作用下,海草床不断退化。食物网是海草床生态系统的重要组成部分,研究食物网营养级之间的相互作用关系对于海草床的生物多样性和稳定性具有重要的意义。通过检索Web of Science和CNKI数据库中收录的海草床食物网营养级相互作用关系的相关文献,从研究区域、种类分布、营养级相互作用类型、环境影响因子以及研究方法等方面进行了文献分析,以期阐明国内外海草床食物网营养级研究相关进展。结果表明:目前的主要研究区域具有一定的地域性,以保护和恢复较好的区域为主;研究的海草种类主要为广泛分布的种类;研究的相互作用类型主要为食物网的部分环节,缺乏对整个营养级动态变化的研究;研究考虑的环境因子主要是富营养化的影响,而对于其他环境因子的动态变化涉及较少;目前的研究方法以模拟实验为主,多偏向于静态或者短期的模拟,缺乏对长期动态变化过程的模拟研究。
