As a typical inland wetland, Yangguan nature reserve wetland in Dunhuang is one of the important stops of migratory route for birds, which is vulnerable and particular. Study on the community characteristics and speci...As a typical inland wetland, Yangguan nature reserve wetland in Dunhuang is one of the important stops of migratory route for birds, which is vulnerable and particular. Study on the community characteristics and species diversity of wetland has great signifi cance for biodiversity protection. Based on the fi eld investigation, the fl oristic composition, geographical elements and species diversity of wetland plants were studied in Yangguan reserve of Dunhuang. The results showed that 26 families, 56 genera and 74 species were recorded in the study area. The largest families were the Gramineae and Chenopodiaceae, accounting for 29.73% of the total. Herbs were the most abundant life-form, accounting for 77.03% of the total. The fl oral geographical elements of the plants were mainly composed of temperate zone distribution type. By using two way indicator species analysis(TWINSPAN), the vegetation in 36 sampling plots could be classifi ed into 8 communities. The species diversity indexes of communities were relatively low, but had large differences among each other. According to the importance value, the Margalef richness index(Rm) ranged from 0 to 4.200. Simpson diversity index(D) was between 0 and 0.512; Shannon diversity index(H) ranged from 0 to 1.400, and Pielou evenness index(J) was within the range of 0.538 to 1.000. The results indicated that the plant species were relatively rare and simple in general, the species diversity of communities was low, and the ecological environment was fragile in Yangguan nature reserve of Dunhuang.展开更多
Ru（II）-complex functionalized silica nanoparticles（nano-SiO2） were prepared via a coordination reaction of cis-dichlorobis（2,2＇-bipyridine）ruthenium[Ru（bpy）2C12] complex with poly（4-vinylpyridine）（P4VP）-m...Ru（II）-complex functionalized silica nanoparticles（nano-SiO2） were prepared via a coordination reaction of cis-dichlorobis（2,2＇-bipyridine）ruthenium[Ru（bpy）2C12] complex with poly（4-vinylpyridine）（P4VP）-modified na- no-SiO2 particles. Both the Ru-complex and the functionalized nano-SiO2P4VP-Ru（bpy） hybrids were doped in poly（methyl methacrylate）（PMMA） to form optically transparent thin films. The composition and spectroscopic properties of the nano-SiO2P4VP-Ru（bpy） hybrids were evaluated with the help of thermogravimetric and elemental analysis, and UV-Vis absorption spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and fluores- cence spectroscopy. Microscopy images revealed that the nanohybrids were approximately 12 nm in diameter and readily formed aggregates following the functionalization with P4VP and Ru（bpy）2C12. The as-prepared na- no-SiO2P4VP-Ru（bpy） hybrids produced emissions at approximately 604 and 654 nm under radiation both in solution and in doped thin films. Finally, cyclic voltammetry studies on the nanohybrid-modified electrode revealed a redox couple with the cathodic and anodic potentials at approximately 0.28 and 0.73 V（vs. Ag/AgCI）, attributed to the one electron transfer of Ru（bpy）22＋/3＋ immobilized on the nano-SiO2 particles.展开更多
基金Sponsored by Global Change Special Funded Project of National Key Scientifi c Research Program(2013CB956000)
文摘As a typical inland wetland, Yangguan nature reserve wetland in Dunhuang is one of the important stops of migratory route for birds, which is vulnerable and particular. Study on the community characteristics and species diversity of wetland has great signifi cance for biodiversity protection. Based on the fi eld investigation, the fl oristic composition, geographical elements and species diversity of wetland plants were studied in Yangguan reserve of Dunhuang. The results showed that 26 families, 56 genera and 74 species were recorded in the study area. The largest families were the Gramineae and Chenopodiaceae, accounting for 29.73% of the total. Herbs were the most abundant life-form, accounting for 77.03% of the total. The fl oral geographical elements of the plants were mainly composed of temperate zone distribution type. By using two way indicator species analysis(TWINSPAN), the vegetation in 36 sampling plots could be classifi ed into 8 communities. The species diversity indexes of communities were relatively low, but had large differences among each other. According to the importance value, the Margalef richness index(Rm) ranged from 0 to 4.200. Simpson diversity index(D) was between 0 and 0.512; Shannon diversity index(H) ranged from 0 to 1.400, and Pielou evenness index(J) was within the range of 0.538 to 1.000. The results indicated that the plant species were relatively rare and simple in general, the species diversity of communities was low, and the ecological environment was fragile in Yangguan nature reserve of Dunhuang.
基金Supported by the National Natural Science Foundation of China（No.21373058）.
文摘Ru（II）-complex functionalized silica nanoparticles（nano-SiO2） were prepared via a coordination reaction of cis-dichlorobis（2,2＇-bipyridine）ruthenium[Ru（bpy）2C12] complex with poly（4-vinylpyridine）（P4VP）-modified na- no-SiO2 particles. Both the Ru-complex and the functionalized nano-SiO2P4VP-Ru（bpy） hybrids were doped in poly（methyl methacrylate）（PMMA） to form optically transparent thin films. The composition and spectroscopic properties of the nano-SiO2P4VP-Ru（bpy） hybrids were evaluated with the help of thermogravimetric and elemental analysis, and UV-Vis absorption spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and fluores- cence spectroscopy. Microscopy images revealed that the nanohybrids were approximately 12 nm in diameter and readily formed aggregates following the functionalization with P4VP and Ru（bpy）2C12. The as-prepared na- no-SiO2P4VP-Ru（bpy） hybrids produced emissions at approximately 604 and 654 nm under radiation both in solution and in doped thin films. Finally, cyclic voltammetry studies on the nanohybrid-modified electrode revealed a redox couple with the cathodic and anodic potentials at approximately 0.28 and 0.73 V（vs. Ag/AgCI）, attributed to the one electron transfer of Ru（bpy）22＋/3＋ immobilized on the nano-SiO2 particles.
