Strong atmospheric turbulence reduces astronomical seeing,causing speckle images acquired by ground-based solar telescopes to become blurred and distorted.Severe distortion in speckle images impedes image phase deviat...Strong atmospheric turbulence reduces astronomical seeing,causing speckle images acquired by ground-based solar telescopes to become blurred and distorted.Severe distortion in speckle images impedes image phase deviation in the speckle masking reconstruction method,leading to the appearance of spurious imaging artifacts.Relying only on linear image degradation principles to reconstruct solar images is insufficient.To solve this problem,we propose the multiframe blind deconvolution combined with non-rigid alignment(MFBD-CNRA)method for solar image reconstruction.We consider image distortion caused by atmospheric turbulence and use non-rigid alignment to correct pixel-level distortion,thereby achieving nonlinear constraints to complement image intensity changes.After creating the corrected speckle image,we use the linear method to solve the wavefront phase,obtaining the target image.We verify the effectiveness of our method results,compared with others,using solar observation data from the 1 m new vacuum solar telescope(NVST).This new method successfully reconstructs high-resolution images of solar observations with a Fried parameter r0 of approximately 10 cm,and enhances images at high frequency.When r0 is approximately 5 cm,the new method is even more effective.It reconstructs the edges of solar graining and sunspots,and is greatly enhanced at mid and high frequency compared with other methods.Comparisons confirm the effectiveness of this method,with respect to both nonlinear and linear constraints in solar image reconstruction.This provides a suitable solution for image reconstruction in ground-based solar observations under strong atmospheric turbulence.展开更多
We present seeing measurements of the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope- LAMOST） site at Xinglong station during the period from 2007 March 12 to Apr...We present seeing measurements of the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope- LAMOST） site at Xinglong station during the period from 2007 March 12 to April 25. The measurements were carried out with the Differential Image Motion Monitor （DIMM）, and a total of 9259 data sets was obtained. The median seeing was measured to be 1.1″, with 25% being better than 0.8″and 75% better than 1.5″. The experiment shows that the DIMM exposure time has significant effects on the results of seeing measurements. An SBIG Polaris seeing monitor, which had been planned to be installed on the LAMOST site for long-term monitoring, was also employed during the DIMM observations. The results show that the SBIG seeing monitor is easily affected by gusty wind, resulting in larger seeing values. Considering the previous seeing measurements at Xinglong station over the last 15 yr, we conclude that an acceptable seeing condition at Xinglong station is around 1″-2″.展开更多
Site testing results indicate that Antarctic Dome A is an excellent ground-based astronomical site suitable for observations ranging from visible to infrared wavelengths. However, the harsh environment in Antarctica, ...Site testing results indicate that Antarctic Dome A is an excellent ground-based astronomical site suitable for observations ranging from visible to infrared wavelengths. However, the harsh environment in Antarctica, especially the very low temperature and atmospheric pressure, always produces frost on the telescopes＇ mirrors, which are exposed to the air. Since the Dome A site is still unattended, the Antarctic telescope tubes are always designed to be filled with dry nitrogen, and the outer surfaces of the optical system are heated by an indium-tin oxide thin film. These precautions can prevent the optical surfaces from frosting over, but they degrade the image quality by introducing additional mirror seeing. Based on testing observations of the second Antarctic Survey Telescope （AST3-2） in the Mohe site in China, mirror seeing resulting from the heated aspheric plate has been measured using micro-thermal sensors. Results comparing the real-time atmospheric seeing monitored by the Differential Image Motion Monitor and real-time examinations of image quality agree well.展开更多
In this article,we present a detailed analysis of the statistical properties of seeing for the Muztaghata site which is a candidate site for hosting the future Chinese Large Optical/infrared Telescope(LOT)project.The ...In this article,we present a detailed analysis of the statistical properties of seeing for the Muztaghata site which is a candidate site for hosting the future Chinese Large Optical/infrared Telescope(LOT)project.The measurements were obtained with differential image motion monitors(DIMMs)from April2017 to November 2018 at different heights during different periods.The median seeings at 11 m and6 m are very close but significantly different from that on the ground.We mainly analyzed the seeing at11 m monthly and hourly,having found that the best season for observing was from late autumn to early winter and seeing tended to improve during the night only in autumn.The analysis of the dependence on temperature inversion,wind speed and direction also was made and the best meteorological conditions for seeing are given.展开更多
The Seeing observation at Gaomeigu station, Lijiang, Yunnan during March, 1995—December, 1996 is introduced in this paper, On the average Fried parameter is equal to 15 34cm (FWHM=0 72″). In the same time, the seein...The Seeing observation at Gaomeigu station, Lijiang, Yunnan during March, 1995—December, 1996 is introduced in this paper, On the average Fried parameter is equal to 15 34cm (FWHM=0 72″). In the same time, the seeing observation in the 46 nights that the observation time was more than five hours is introduced. On the average Fried parameter is r 0=16 5cm (FWHM=0 67″). For the best seeing on an average r 0=22 36cm (FWHM=0 49″). The mininum on an average is r 0=12 95cm (FWHM=0 85″).展开更多
China is the manufacturing hub of the world, and its huge market demands have contributed to the large inflow of foreign capital. As the Chinese economy has entered the ＂new normal＂, the market has seen both an infl...China is the manufacturing hub of the world, and its huge market demands have contributed to the large inflow of foreign capital. As the Chinese economy has entered the ＂new normal＂, the market has seen both an inflow and exodus of foreign capital. Is the exodus of foreign capital from China really under way？展开更多
“Kan”and“Jian”are both sense verbs in Chinese,but they can develop into multiple meanings and usage.In order to prove that the language in communication assumes the collective cultural experience and historical ba...“Kan”and“Jian”are both sense verbs in Chinese,but they can develop into multiple meanings and usage.In order to prove that the language in communication assumes the collective cultural experience and historical background,this article attempts,from the connection and differentiation between various meanings,to sort out how the semantic structure is defined in accordance with the situations where the words are used.In addition,based on the methods of the diachronic research and synchronic research,this article also observes the semantic evolution and the extensive concepts of imitation and implication.展开更多
LIU GUIJIN is a Chinese face familiar to many African TV viewers. The 67-year-old has been involved with the continent for more than 30 years as a Chinese diplomat. He＇s the first Special Representative of the Chines...LIU GUIJIN is a Chinese face familiar to many African TV viewers. The 67-year-old has been involved with the continent for more than 30 years as a Chinese diplomat. He＇s the first Special Representative of the Chinese Government for African Affairs.展开更多
WHEN I grew up in Ghana, the only information children within my age bracket （10-15） had about China was that it is a populous country with rice as the staple food for its people. Therefore those of us who were alwa...WHEN I grew up in Ghana, the only information children within my age bracket （10-15） had about China was that it is a populous country with rice as the staple food for its people. Therefore those of us who were always crying for rice were referred to as ＂Chinese.＂ We were also fascinated by the few Chinese names we heard on air and how some news presenters fumbled to mention names such as Wang, Chen, Sun, Li among others, which we considered as following the pattern of a rhyme.展开更多
The expansion of China-Africa relations in recent years has led to a deepening of connections between the Chinese and African peoples. Important events in China and Africa are attracting a lot of interest from both si...The expansion of China-Africa relations in recent years has led to a deepening of connections between the Chinese and African peoples. Important events in China and Africa are attracting a lot of interest from both sides. One of these events is the annual sessions of the National People＇s Congress （NPC） and the Chinese People＇s Political Consultative Conference （CPPCC）,展开更多
为了进一步研究后张预应力装配耗能框架(Post-Tensioned Energy Dissipating,PTED框架)的抗震性能,开展了基于增量动力分析方法(IDA)的地震易损性分析和抗倒塌研究。以直接基于位移设计的四层三跨PTED框架为基本原型,建立了Open SEES非...为了进一步研究后张预应力装配耗能框架(Post-Tensioned Energy Dissipating,PTED框架)的抗震性能,开展了基于增量动力分析方法(IDA)的地震易损性分析和抗倒塌研究。以直接基于位移设计的四层三跨PTED框架为基本原型,建立了Open SEES非线性分析模型,并选取10条地震动记录对其进行IDA分析。结果表明,不同于普通钢筋混凝土框架的单项损伤指标,PTED结构需考虑最大预应力筋合力和最大层间位移角的双项损伤指标。结合IDA分析结果建立了地震需求模型,得到了结构模型的易损性曲线和抗倒塌概率曲线。PTED框架在设防大震作用下倒塌概率为0.2%,表明其具有较好的抗倒塌能力。展开更多
基金sponsored by the National Natural Science Foundation of China(NSFC)under the grant numbers(11773073,11873027,U2031140,11833010)Yunnan Key Laboratory of Solar Physics and Space Science under the number 202205AG070009+1 种基金Yunnan Provincial Science and Technology Department(202103AD50013,202105AB160001,202305AH340002)the GHfund A202302013242 and CAS“Light of West China”Program 202305AS350029.
文摘Strong atmospheric turbulence reduces astronomical seeing,causing speckle images acquired by ground-based solar telescopes to become blurred and distorted.Severe distortion in speckle images impedes image phase deviation in the speckle masking reconstruction method,leading to the appearance of spurious imaging artifacts.Relying only on linear image degradation principles to reconstruct solar images is insufficient.To solve this problem,we propose the multiframe blind deconvolution combined with non-rigid alignment(MFBD-CNRA)method for solar image reconstruction.We consider image distortion caused by atmospheric turbulence and use non-rigid alignment to correct pixel-level distortion,thereby achieving nonlinear constraints to complement image intensity changes.After creating the corrected speckle image,we use the linear method to solve the wavefront phase,obtaining the target image.We verify the effectiveness of our method results,compared with others,using solar observation data from the 1 m new vacuum solar telescope(NVST).This new method successfully reconstructs high-resolution images of solar observations with a Fried parameter r0 of approximately 10 cm,and enhances images at high frequency.When r0 is approximately 5 cm,the new method is even more effective.It reconstructs the edges of solar graining and sunspots,and is greatly enhanced at mid and high frequency compared with other methods.Comparisons confirm the effectiveness of this method,with respect to both nonlinear and linear constraints in solar image reconstruction.This provides a suitable solution for image reconstruction in ground-based solar observations under strong atmospheric turbulence.
基金supported by the National Natural Science Foundation of China(Grant Nos.10903014 and10778709)supported by the Young Researcher Grant of National Astronomical Observatories,Chinese Academy of Sciences
文摘We present seeing measurements of the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope- LAMOST） site at Xinglong station during the period from 2007 March 12 to April 25. The measurements were carried out with the Differential Image Motion Monitor （DIMM）, and a total of 9259 data sets was obtained. The median seeing was measured to be 1.1″, with 25% being better than 0.8″and 75% better than 1.5″. The experiment shows that the DIMM exposure time has significant effects on the results of seeing measurements. An SBIG Polaris seeing monitor, which had been planned to be installed on the LAMOST site for long-term monitoring, was also employed during the DIMM observations. The results show that the SBIG seeing monitor is easily affected by gusty wind, resulting in larger seeing values. Considering the previous seeing measurements at Xinglong station over the last 15 yr, we conclude that an acceptable seeing condition at Xinglong station is around 1″-2″.
基金supported by the China Polar Science Strategy Research Fund project (Grant no. 20120314)the National Natural Science Foundation of China (Grant no. 11190013)
文摘Site testing results indicate that Antarctic Dome A is an excellent ground-based astronomical site suitable for observations ranging from visible to infrared wavelengths. However, the harsh environment in Antarctica, especially the very low temperature and atmospheric pressure, always produces frost on the telescopes＇ mirrors, which are exposed to the air. Since the Dome A site is still unattended, the Antarctic telescope tubes are always designed to be filled with dry nitrogen, and the outer surfaces of the optical system are heated by an indium-tin oxide thin film. These precautions can prevent the optical surfaces from frosting over, but they degrade the image quality by introducing additional mirror seeing. Based on testing observations of the second Antarctic Survey Telescope （AST3-2） in the Mohe site in China, mirror seeing resulting from the heated aspheric plate has been measured using micro-thermal sensors. Results comparing the real-time atmospheric seeing monitored by the Differential Image Motion Monitor and real-time examinations of image quality agree well.
基金supported by theNational Nature Science Foundation of China(Grant Nos.11873081 and 11603065)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administered by the Chinese Academy of Sciences。
文摘In this article,we present a detailed analysis of the statistical properties of seeing for the Muztaghata site which is a candidate site for hosting the future Chinese Large Optical/infrared Telescope(LOT)project.The measurements were obtained with differential image motion monitors(DIMMs)from April2017 to November 2018 at different heights during different periods.The median seeings at 11 m and6 m are very close but significantly different from that on the ground.We mainly analyzed the seeing at11 m monthly and hourly,having found that the best season for observing was from late autumn to early winter and seeing tended to improve during the night only in autumn.The analysis of the dependence on temperature inversion,wind speed and direction also was made and the best meteorological conditions for seeing are given.
文摘The Seeing observation at Gaomeigu station, Lijiang, Yunnan during March, 1995—December, 1996 is introduced in this paper, On the average Fried parameter is equal to 15 34cm (FWHM=0 72″). In the same time, the seeing observation in the 46 nights that the observation time was more than five hours is introduced. On the average Fried parameter is r 0=16 5cm (FWHM=0 67″). For the best seeing on an average r 0=22 36cm (FWHM=0 49″). The mininum on an average is r 0=12 95cm (FWHM=0 85″).
文摘China is the manufacturing hub of the world, and its huge market demands have contributed to the large inflow of foreign capital. As the Chinese economy has entered the ＂new normal＂, the market has seen both an inflow and exodus of foreign capital. Is the exodus of foreign capital from China really under way？
文摘“Kan”and“Jian”are both sense verbs in Chinese,but they can develop into multiple meanings and usage.In order to prove that the language in communication assumes the collective cultural experience and historical background,this article attempts,from the connection and differentiation between various meanings,to sort out how the semantic structure is defined in accordance with the situations where the words are used.In addition,based on the methods of the diachronic research and synchronic research,this article also observes the semantic evolution and the extensive concepts of imitation and implication.
文摘LIU GUIJIN is a Chinese face familiar to many African TV viewers. The 67-year-old has been involved with the continent for more than 30 years as a Chinese diplomat. He＇s the first Special Representative of the Chinese Government for African Affairs.
文摘WHEN I grew up in Ghana, the only information children within my age bracket （10-15） had about China was that it is a populous country with rice as the staple food for its people. Therefore those of us who were always crying for rice were referred to as ＂Chinese.＂ We were also fascinated by the few Chinese names we heard on air and how some news presenters fumbled to mention names such as Wang, Chen, Sun, Li among others, which we considered as following the pattern of a rhyme.
文摘The expansion of China-Africa relations in recent years has led to a deepening of connections between the Chinese and African peoples. Important events in China and Africa are attracting a lot of interest from both sides. One of these events is the annual sessions of the National People＇s Congress （NPC） and the Chinese People＇s Political Consultative Conference （CPPCC）,
文摘为了进一步研究后张预应力装配耗能框架(Post-Tensioned Energy Dissipating,PTED框架)的抗震性能,开展了基于增量动力分析方法(IDA)的地震易损性分析和抗倒塌研究。以直接基于位移设计的四层三跨PTED框架为基本原型,建立了Open SEES非线性分析模型,并选取10条地震动记录对其进行IDA分析。结果表明,不同于普通钢筋混凝土框架的单项损伤指标,PTED结构需考虑最大预应力筋合力和最大层间位移角的双项损伤指标。结合IDA分析结果建立了地震需求模型,得到了结构模型的易损性曲线和抗倒塌概率曲线。PTED框架在设防大震作用下倒塌概率为0.2%,表明其具有较好的抗倒塌能力。
