The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area.The result showed that for a pure snow spectrum,the snow reflectance peaks appeared from ...The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area.The result showed that for a pure snow spectrum,the snow reflectance peaks appeared from visible to 800 nm band locations;there was an obvious absorption valley of snow spectrum near 1 030 nm wavelength.Compared with fresh snow,the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300～1 300,1 700～1 800 and 2 200～2 300 nm,the lowest was from the compacted snow and frozen ice.For the vegetation and snow mixed spectral characteristics,it was indicated that the spectral reflectance increased for the snow-covered land types(including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350～1 300 nm.However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic.In the end,based on the spectrum analysis of snow,vegetation,and mixed snow/vegetation pixels,the mixed spectral fitting equations were established,and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones(correlation coefficient R2=0.950 9).展开更多
我国新一代中国频谱射电日像仪(Chinese Spectral Radio Heliograph,CSRH)原始观测数据采用自定义格式,在进行后续处理与共享使用时必须转换相应的格式。在分析FITS-IDI(FITS Interferometry Data Interchange)格式的基础上,结合CSRH的...我国新一代中国频谱射电日像仪(Chinese Spectral Radio Heliograph,CSRH)原始观测数据采用自定义格式,在进行后续处理与共享使用时必须转换相应的格式。在分析FITS-IDI(FITS Interferometry Data Interchange)格式的基础上,结合CSRH的实际观测模式与数据产出方式,定义与设计了符合项目情况的FITS-IDI格式及字段,并对FITS-IDI文件中若干字段的值如何获取、计算进行了深入讨论。根据定义生成的FITS-IDI文件已成功导入CASA软件,并可以进行后续处理。经过对CASA测量集文件的核实,证明了数据生成的正确性。本研究有效地推进了CSRH的建设工作,也对其他射电干涉阵数据存储有一定的参考价值。展开更多
Antimony selenide(Sb2Se3) films are widely used in phase change memory and solar cells due to their stable switching effect and excellent photovoltaic properties. These properties of the films are affected by the film...Antimony selenide(Sb2Se3) films are widely used in phase change memory and solar cells due to their stable switching effect and excellent photovoltaic properties. These properties of the films are affected by the film thickness. A method combining the advantages of Levenberg–Marquardt method and spectral fitting method(LM–SFM) is presented to study the dependence of refractive index(RI), absorption coefficient, optical band gap, Wemple–Di Domenico parameters, dielectric constant and optical electronegativity of the Sb2Se3films on their thickness. The results show that the RI and absorption coefficient of the Sb2Se3films increase with the increase of film thickness, while the optical band gap decreases with the increase of film thickness. Finally, the reasons why the optical and electrical properties of the film change with its thickness are explained by x-ray diffractometer(XRD), energy dispersive x-ray spectrometer(EDS), Mott–Davis state density model and Raman microstructure analysis.展开更多
基金National Natural Science Foundation of China(40771147)Global Change Research Projects of Key National Scientific Research Plan(2010CB951302)the Social Commonweal Meteorological Research Project(GYHY201106027)
文摘The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area.The result showed that for a pure snow spectrum,the snow reflectance peaks appeared from visible to 800 nm band locations;there was an obvious absorption valley of snow spectrum near 1 030 nm wavelength.Compared with fresh snow,the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300～1 300,1 700～1 800 and 2 200～2 300 nm,the lowest was from the compacted snow and frozen ice.For the vegetation and snow mixed spectral characteristics,it was indicated that the spectral reflectance increased for the snow-covered land types(including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350～1 300 nm.However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic.In the end,based on the spectrum analysis of snow,vegetation,and mixed snow/vegetation pixels,the mixed spectral fitting equations were established,and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones(correlation coefficient R2=0.950 9).
文摘我国新一代中国频谱射电日像仪(Chinese Spectral Radio Heliograph,CSRH)原始观测数据采用自定义格式,在进行后续处理与共享使用时必须转换相应的格式。在分析FITS-IDI(FITS Interferometry Data Interchange)格式的基础上,结合CSRH的实际观测模式与数据产出方式,定义与设计了符合项目情况的FITS-IDI格式及字段,并对FITS-IDI文件中若干字段的值如何获取、计算进行了深入讨论。根据定义生成的FITS-IDI文件已成功导入CASA软件,并可以进行后续处理。经过对CASA测量集文件的核实,证明了数据生成的正确性。本研究有效地推进了CSRH的建设工作,也对其他射电干涉阵数据存储有一定的参考价值。
基金supported by the National Natural Science Foundation of China (Grant Nos. 62075109, 62135011, 62075107, and 61935006)K. C. Wong Magna Fund in Ningbo University。
文摘Antimony selenide(Sb2Se3) films are widely used in phase change memory and solar cells due to their stable switching effect and excellent photovoltaic properties. These properties of the films are affected by the film thickness. A method combining the advantages of Levenberg–Marquardt method and spectral fitting method(LM–SFM) is presented to study the dependence of refractive index(RI), absorption coefficient, optical band gap, Wemple–Di Domenico parameters, dielectric constant and optical electronegativity of the Sb2Se3films on their thickness. The results show that the RI and absorption coefficient of the Sb2Se3films increase with the increase of film thickness, while the optical band gap decreases with the increase of film thickness. Finally, the reasons why the optical and electrical properties of the film change with its thickness are explained by x-ray diffractometer(XRD), energy dispersive x-ray spectrometer(EDS), Mott–Davis state density model and Raman microstructure analysis.
