During the total solar eclipse on July 22, 2009 in Wuhan, the joint observation test of Na layer and ionosphere was conducted by using the daytime observation atmospheric lidar and the GPS ionosphere detector. The res...During the total solar eclipse on July 22, 2009 in Wuhan, the joint observation test of Na layer and ionosphere was conducted by using the daytime observation atmospheric lidar and the GPS ionosphere detector. The results show that the full width at half maximum(FWHM) of Na layer density slightly narrowed during the total solar eclipse and broadened after the eclipse, while the height of Na peak slightly decreased in the eclipse and increased after the eclipse. These implying that Na layer changes reflect the rapid process of sunrise and sunset. The ionosphere total electron content(TEC) and the sky background light noise also presented an obvious fluctuation characteristic with the changes of solar irradiation during the process of total solar eclipse. The difference lies in that the changes of FWHM of Na layer atoms are much slower than that of ionosphere, the reason for this might be that the Na layer, after being disturbed by the total solar eclipse, will generate a series of complicated photochemical reactions and momentum transport processes, and then recombine the Na atoms. The Na atoms to be detected by the lidar need a lag process, which rightly conforms to the theoretical simulated results.展开更多
The 2D-layer compound ([Na-2(C8H12N2O3)(4)(C2H6SO)(4)(W6O19)](n) 1, M-r = 2133.98) synthesized by the reaction of sodium tungstate and barbitone sodium in the solution of DMSO and water has been characterized by IR an...The 2D-layer compound ([Na-2(C8H12N2O3)(4)(C2H6SO)(4)(W6O19)](n) 1, M-r = 2133.98) synthesized by the reaction of sodium tungstate and barbitone sodium in the solution of DMSO and water has been characterized by IR and Raman spectra, elemental analysis and TGA. X-ray diffraction analysis indicates that Compound 1 crystallizes in the monoclinic system, space group C2/c with a 14.8026(4), b = 17.3012(3), c = 19.6379(5) A, beta = 98.6300 degrees, V = 4972.4(2) angstrom(3), Z = 4, F(000) 3928, D-c = 2.851 and mu = 14.101 mm(-1). 1 has a two-dimensional layer structure with hexapolyoxotungstate building blocks and coordinated sodium chains.展开更多
采用共沉淀法制备碳酸盐前驱体,通过高温固相反应制备Na+掺杂的富锂锰基正极材料Li1.2-xNaxNi0.13Co0.13Mn0.54O2(x=0,0.01,0.02,0.04,0.08).X射线衍射(XRD)和扫描电镜(SEM)分析表明,x≤0.04时为层状富锂锰基材料的α-NaFeO 2六方相结构...采用共沉淀法制备碳酸盐前驱体,通过高温固相反应制备Na+掺杂的富锂锰基正极材料Li1.2-xNaxNi0.13Co0.13Mn0.54O2(x=0,0.01,0.02,0.04,0.08).X射线衍射(XRD)和扫描电镜(SEM)分析表明,x≤0.04时为层状富锂锰基材料的α-NaFeO 2六方相结构,Na掺杂量过大时颗粒表面出现团聚絮状物并发现第二相—P2型层状氧化物.电化学测试发现适量的Na掺杂可提高材料的比容量、倍率和循环性能;掺杂量为0.02时电化学性能最佳:在2.0~4.6 V充放电,Li 1.18 Na 0.02 Ni 0.13 Co 0.13 Mn 0.54 O 2在0.1 C放电比容量为273.4 mAh/g,首次库伦效率为93.1%,1C循环100次后容量超过200 mAh/g,保持率为84.3%.离子半径较大的Na+占据Li位,起到柱撑作用,稳定了结构,增大了层间距,利于Li^+扩散;此外,材料表面形成的P2型层状氧化物能够减缓层状结构向尖晶石结构的转变,从而提高了电化学性能.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.1097800341104101+1 种基金41101334)the National High-tech R&D Program
文摘During the total solar eclipse on July 22, 2009 in Wuhan, the joint observation test of Na layer and ionosphere was conducted by using the daytime observation atmospheric lidar and the GPS ionosphere detector. The results show that the full width at half maximum(FWHM) of Na layer density slightly narrowed during the total solar eclipse and broadened after the eclipse, while the height of Na peak slightly decreased in the eclipse and increased after the eclipse. These implying that Na layer changes reflect the rapid process of sunrise and sunset. The ionosphere total electron content(TEC) and the sky background light noise also presented an obvious fluctuation characteristic with the changes of solar irradiation during the process of total solar eclipse. The difference lies in that the changes of FWHM of Na layer atoms are much slower than that of ionosphere, the reason for this might be that the Na layer, after being disturbed by the total solar eclipse, will generate a series of complicated photochemical reactions and momentum transport processes, and then recombine the Na atoms. The Na atoms to be detected by the lidar need a lag process, which rightly conforms to the theoretical simulated results.
基金The project was supported by the 973 program of the MOST (001CB108906), the National Natural Science Foundation of China (20425313, 20333070 and 20303021), the Natural Science Foundation of Fujian Province, the Chinese Academy of Sciences and Fujian University of Technology (GY-Z0321)
文摘The 2D-layer compound ([Na-2(C8H12N2O3)(4)(C2H6SO)(4)(W6O19)](n) 1, M-r = 2133.98) synthesized by the reaction of sodium tungstate and barbitone sodium in the solution of DMSO and water has been characterized by IR and Raman spectra, elemental analysis and TGA. X-ray diffraction analysis indicates that Compound 1 crystallizes in the monoclinic system, space group C2/c with a 14.8026(4), b = 17.3012(3), c = 19.6379(5) A, beta = 98.6300 degrees, V = 4972.4(2) angstrom(3), Z = 4, F(000) 3928, D-c = 2.851 and mu = 14.101 mm(-1). 1 has a two-dimensional layer structure with hexapolyoxotungstate building blocks and coordinated sodium chains.
文摘采用共沉淀法制备碳酸盐前驱体,通过高温固相反应制备Na+掺杂的富锂锰基正极材料Li1.2-xNaxNi0.13Co0.13Mn0.54O2(x=0,0.01,0.02,0.04,0.08).X射线衍射(XRD)和扫描电镜(SEM)分析表明,x≤0.04时为层状富锂锰基材料的α-NaFeO 2六方相结构,Na掺杂量过大时颗粒表面出现团聚絮状物并发现第二相—P2型层状氧化物.电化学测试发现适量的Na掺杂可提高材料的比容量、倍率和循环性能;掺杂量为0.02时电化学性能最佳:在2.0~4.6 V充放电,Li 1.18 Na 0.02 Ni 0.13 Co 0.13 Mn 0.54 O 2在0.1 C放电比容量为273.4 mAh/g,首次库伦效率为93.1%,1C循环100次后容量超过200 mAh/g,保持率为84.3%.离子半径较大的Na+占据Li位,起到柱撑作用,稳定了结构,增大了层间距,利于Li^+扩散;此外,材料表面形成的P2型层状氧化物能够减缓层状结构向尖晶石结构的转变,从而提高了电化学性能.
