Isomerism is an essential and widespread phenomenon in organic chemistry but rarely observed in covalent organic frameworks(COFs),a novel class of crystalline porous organic polymers with versatile applications.Herein...Isomerism is an essential and widespread phenomenon in organic chemistry but rarely observed in covalent organic frameworks(COFs),a novel class of crystalline porous organic polymers with versatile applications.Herein,we give an account of the first example of a controllable synthesis of constitutional isomers of a COF.The two isomers exhibited marked differences in their gas/vapor adsorption behaviors and chemical stability in various solvents.Furthermore,structure transformation from one isomer to the other was realized.This work not only paves the way for rational design and synthesis of COF isomers but also provides a vivid example of structure–property relationship in crystalline porous polymers.展开更多
Objective:The aim of paper is to find ecological suitable regionalization of Melicope ptelefolia planting and provide a reference for the rational planning of Good Agricultural Practices(GAP).Methods:The natural ecolo...Objective:The aim of paper is to find ecological suitable regionalization of Melicope ptelefolia planting and provide a reference for the rational planning of Good Agricultural Practices(GAP).Methods:The natural ecological niches of Melicope ptelefolia was taken as basic point.The adaptable areas of Melicope ptelefolia was analysed throughout the whole nation by using Geographic Information System for Traditional Chinese Medicine(TCMGIS).Results:Besides the original distribbution region of Guangxi,Guangdong,Hainan,Yunnan,Fujian,Jiangxi,Hunan,Guizhou,we further found that Zhejiang,Taiwan,Hong Kong,Chongqing,Sichuan are adaptable for the growth of Melicope ptelefolia.The most suitable region is Guangxi,and the followed is Guangdong.Conclusion:The ecological suitable area of Melicope ptelefolia mainly distributes in Lingnan Region,and TCMGIS is comparatively scientific and accurate to analyze suitable areas for the growth of Melicope ptelefolia.These findings have important reference value for the introduction,cultivation and scientific planning of Melicope ptelefolia.展开更多
[Objective] To develop a solid phase extraction-high performance liquid chromatography-fluorescence method for determination of quin- olone antibiotics in water. [ Metbod] The standard curves of four quinolones （norf...[Objective] To develop a solid phase extraction-high performance liquid chromatography-fluorescence method for determination of quin- olone antibiotics in water. [ Metbod] The standard curves of four quinolones （norfloxacin, ciprofloxacin, Iomefloxacin and enrofloxacin） were pre- pared. The detection limit in water and recovery were determined. The water samples collected from different areas, river and tap water were trea- ted using solid-phese extraction method and analyzed by high performance liquid chromatography. Then the concentration of quinolones antibiotics was determined by fluorescence method. [ Result] The detection limit of quinolone antibiotics in water was 0.083 -0.248 μg/L, and their recovery was 63.7% -134.1%. The four quinolone antibiotics at different levels were detected in various water samples, and the total concentration of quin- olone antibiotics was 0.045 -3.969 μg/L. The total concentration of quinolone antibiotics was higher in the water samples collected from rivers in Shenzhen area than in the sewage samples. The four quinolone antibiotics could be detected in all tap water samples. [ CoaduLsion ] The solid phase extraction-high performance liquid chromatography-fluorescence method is feasible and effective to detect quinolones in water. In addition, this method needs low cost and can meet requirements of daily monitorina and analysis.展开更多
基金the National Science Fund for Distinguished Young Scholars of China(no.21725404)Shanghai Scientific and Technological Innovation Project(18JC1410600)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB20000000)for financial support.
文摘Isomerism is an essential and widespread phenomenon in organic chemistry but rarely observed in covalent organic frameworks(COFs),a novel class of crystalline porous organic polymers with versatile applications.Herein,we give an account of the first example of a controllable synthesis of constitutional isomers of a COF.The two isomers exhibited marked differences in their gas/vapor adsorption behaviors and chemical stability in various solvents.Furthermore,structure transformation from one isomer to the other was realized.This work not only paves the way for rational design and synthesis of COF isomers but also provides a vivid example of structure–property relationship in crystalline porous polymers.
文摘Objective:The aim of paper is to find ecological suitable regionalization of Melicope ptelefolia planting and provide a reference for the rational planning of Good Agricultural Practices(GAP).Methods:The natural ecological niches of Melicope ptelefolia was taken as basic point.The adaptable areas of Melicope ptelefolia was analysed throughout the whole nation by using Geographic Information System for Traditional Chinese Medicine(TCMGIS).Results:Besides the original distribbution region of Guangxi,Guangdong,Hainan,Yunnan,Fujian,Jiangxi,Hunan,Guizhou,we further found that Zhejiang,Taiwan,Hong Kong,Chongqing,Sichuan are adaptable for the growth of Melicope ptelefolia.The most suitable region is Guangxi,and the followed is Guangdong.Conclusion:The ecological suitable area of Melicope ptelefolia mainly distributes in Lingnan Region,and TCMGIS is comparatively scientific and accurate to analyze suitable areas for the growth of Melicope ptelefolia.These findings have important reference value for the introduction,cultivation and scientific planning of Melicope ptelefolia.
基金funded by the grants from the China Natural Science Foundation ( 30671208 and 40773062)Key Project of Guangdong Natural Science Foundation ( 07117909)Science and Technology Planning Project of Guangdong Province( 2005B20801002 and 2006B20601003)
文摘[Objective] To develop a solid phase extraction-high performance liquid chromatography-fluorescence method for determination of quin- olone antibiotics in water. [ Metbod] The standard curves of four quinolones （norfloxacin, ciprofloxacin, Iomefloxacin and enrofloxacin） were pre- pared. The detection limit in water and recovery were determined. The water samples collected from different areas, river and tap water were trea- ted using solid-phese extraction method and analyzed by high performance liquid chromatography. Then the concentration of quinolones antibiotics was determined by fluorescence method. [ Result] The detection limit of quinolone antibiotics in water was 0.083 -0.248 μg/L, and their recovery was 63.7% -134.1%. The four quinolone antibiotics at different levels were detected in various water samples, and the total concentration of quin- olone antibiotics was 0.045 -3.969 μg/L. The total concentration of quinolone antibiotics was higher in the water samples collected from rivers in Shenzhen area than in the sewage samples. The four quinolone antibiotics could be detected in all tap water samples. [ CoaduLsion ] The solid phase extraction-high performance liquid chromatography-fluorescence method is feasible and effective to detect quinolones in water. In addition, this method needs low cost and can meet requirements of daily monitorina and analysis.
