I returned to China from the United Kingdom in 1953, then worked in Purple Mountain Observatory. It was the early days of new China. The elder generation of astronomers was undertaking an effort of ＂repairing broken ...I returned to China from the United Kingdom in 1953, then worked in Purple Mountain Observatory. It was the early days of new China. The elder generation of astronomers was undertaking an effort of ＂repairing broken and filling defect＂ during those post-war years, and started planning and lay- ing the foundation of modern astronomy. Under their leadership, I started a journey of astronomy whose main task was construction. The journey has been full of twists and turns. As a result of the ＂Great Leap Forward＂ in 1958 and the 1966 launch of the decade-long ＂Cultural Revolution＂ period, the situation of construction in astronomy was similar to that in other sciences, suffering bad effects. Not until the ＂Reform and Opening up＂ period after those events was construction able to continue, and various disciplines and international connections began to open. A ＂passage＂ had gradually developed. In this new circumstance, I kept pursuing the pioneers to explore a forward direction. Looking back today, this journey has been three periods of a four generation relay. This article is divided into three sections that describe my research work in these times that I recall： （1） Looking back at the beginning of the return and tracing the footprints of the founders. （2） Recalling my radio astronomy tour. （3） Retrospection and expectation of LAMOST.展开更多
Scientific journals usually mirror the development of a country or area in a specific period of time. With the transnational scientific communication model of today＇s world, the internationalization of scientific jou...Scientific journals usually mirror the development of a country or area in a specific period of time. With the transnational scientific communication model of today＇s world, the internationalization of scientific journals not only provides an avenue for researchers to attain their rights to receive and impart information and ideas openly and freely across a global platform, but the increased reach of such publications allows for a broader and stronger voice in regards to academic and scientific debates.展开更多
Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currentl...Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currently,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM prediction.Besides,the weighted LS+AR hybrid method performs well for PM short-term prediction.However,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR model.In this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid method.By using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid method.Compared to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,respectively.Besides,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.展开更多
This paper proposes a semi-empirical model to predict a ship’s speed loss at arbitrary wave heading.In the model,the formulas that estimate a ship’s added resistance due to waves attacking from different heading ang...This paper proposes a semi-empirical model to predict a ship’s speed loss at arbitrary wave heading.In the model,the formulas that estimate a ship’s added resistance due to waves attacking from different heading angles have been further developed.A correction factor is proposed to consider the nonlinear effect due to large waves in power estimation.The formulas are developed and verified by model tests of 5 ships in regular waves with various heading angles.The full-scale measurements from three different types of ships,i.e.,a PCTC,a container ship,and a chemical tanker,are used to validate the proposed model for speed loss prediction in irregular waves.The effect of the improved model for speed loss prediction on a ship’s voyage optimization is also investigated.The results indicate that a ship’s voyage optimization solutions can be significantly affected by the prediction accuracy of speed loss caused by waves.展开更多
'Asahi Kasei China Fashion Designer Creative awards'2017 S/S collection Show was held in Beijing Hotel to announce the theme of the nineteenth award-winning designer Richard Li’s works show on the evening of ...'Asahi Kasei China Fashion Designer Creative awards'2017 S/S collection Show was held in Beijing Hotel to announce the theme of the nineteenth award-winning designer Richard Li’s works show on the evening of October 29,2016.This event is directly hosted by the China Fashion Week Organizing Committee,Asahi Kasei Corporation and Asahi Kasei Textile Corporation and Hong Kong Fashion Designers Association展开更多
Voyagers,the first and the only mission sent by human beings beyond the end of the solar wind,might be out of service in just several years.In the cosmos beyond 2025,very likely no artificial detector will be flying a...Voyagers,the first and the only mission sent by human beings beyond the end of the solar wind,might be out of service in just several years.In the cosmos beyond 2025,very likely no artificial detector will be flying at the outer brim of the solar system.The Interstellar Express,a mission proposed by CAS scientists,might come timely as a possible successor to fill in the gap.Unlike Voyagers,its detectors are expected to fly not only to the nose part of the heliosphere,but also the tail part and the altitude dimension.As planned in the shortterm stage of its three-step layout,the first two detectors will be launched by the end of 2025,if everything goes well.展开更多
文摘I returned to China from the United Kingdom in 1953, then worked in Purple Mountain Observatory. It was the early days of new China. The elder generation of astronomers was undertaking an effort of ＂repairing broken and filling defect＂ during those post-war years, and started planning and lay- ing the foundation of modern astronomy. Under their leadership, I started a journey of astronomy whose main task was construction. The journey has been full of twists and turns. As a result of the ＂Great Leap Forward＂ in 1958 and the 1966 launch of the decade-long ＂Cultural Revolution＂ period, the situation of construction in astronomy was similar to that in other sciences, suffering bad effects. Not until the ＂Reform and Opening up＂ period after those events was construction able to continue, and various disciplines and international connections began to open. A ＂passage＂ had gradually developed. In this new circumstance, I kept pursuing the pioneers to explore a forward direction. Looking back today, this journey has been three periods of a four generation relay. This article is divided into three sections that describe my research work in these times that I recall： （1） Looking back at the beginning of the return and tracing the footprints of the founders. （2） Recalling my radio astronomy tour. （3） Retrospection and expectation of LAMOST.
文摘Scientific journals usually mirror the development of a country or area in a specific period of time. With the transnational scientific communication model of today＇s world, the internationalization of scientific journals not only provides an avenue for researchers to attain their rights to receive and impart information and ideas openly and freely across a global platform, but the increased reach of such publications allows for a broader and stronger voice in regards to academic and scientific debates.
基金supported by National Natural Science Foundation of China,China(No.42004016)HuBei Natural Science Fund,China(No.2020CFB329)+1 种基金HuNan Natural Science Fund,China(No.2023JJ60559,2023JJ60560)the State Key Laboratory of Geodesy and Earth’s Dynamics self-deployment project,China(No.S21L6101)。
文摘Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currently,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM prediction.Besides,the weighted LS+AR hybrid method performs well for PM short-term prediction.However,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR model.In this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid method.By using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid method.Compared to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,respectively.Besides,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.
基金Open access funding provided by Chalmers University of Technology.The authors acknowledge the financial support from the European Commission(Horizon 2020)project EcoSail(Grant Number 820593)We are also grateful to the support from the Swedish Foundation for International Cooperation in Research and Higher Education(CH2016-6673)+1 种基金National Natural Science Foundation of China(NSFC-51779202)The second author thanks the funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie(Grant Number 754412)and VGR MoRE2020.
文摘This paper proposes a semi-empirical model to predict a ship’s speed loss at arbitrary wave heading.In the model,the formulas that estimate a ship’s added resistance due to waves attacking from different heading angles have been further developed.A correction factor is proposed to consider the nonlinear effect due to large waves in power estimation.The formulas are developed and verified by model tests of 5 ships in regular waves with various heading angles.The full-scale measurements from three different types of ships,i.e.,a PCTC,a container ship,and a chemical tanker,are used to validate the proposed model for speed loss prediction in irregular waves.The effect of the improved model for speed loss prediction on a ship’s voyage optimization is also investigated.The results indicate that a ship’s voyage optimization solutions can be significantly affected by the prediction accuracy of speed loss caused by waves.
文摘'Asahi Kasei China Fashion Designer Creative awards'2017 S/S collection Show was held in Beijing Hotel to announce the theme of the nineteenth award-winning designer Richard Li’s works show on the evening of October 29,2016.This event is directly hosted by the China Fashion Week Organizing Committee,Asahi Kasei Corporation and Asahi Kasei Textile Corporation and Hong Kong Fashion Designers Association
文摘Voyagers,the first and the only mission sent by human beings beyond the end of the solar wind,might be out of service in just several years.In the cosmos beyond 2025,very likely no artificial detector will be flying at the outer brim of the solar system.The Interstellar Express,a mission proposed by CAS scientists,might come timely as a possible successor to fill in the gap.Unlike Voyagers,its detectors are expected to fly not only to the nose part of the heliosphere,but also the tail part and the altitude dimension.As planned in the shortterm stage of its three-step layout,the first two detectors will be launched by the end of 2025,if everything goes well.
