Preface: Key technologies for enhancing the performance of FAST     

Peng Jiang  Zhi-Qiang Shen  Ren-Xin Xu 《天文和天体物理学研究(英文版)》2020,(5):63-64

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)passed its national acceptance inspection on 2020 January 11.This special issue includes a total of 15 papers,which are selected to introduce the status of FAST’s performance and demonstrate the key technologies applied to FAST.The presented performance parameters can provide an important reference for scientists to propose observations with FAST.The key technologies presented in these papers include design and implementation in the measurement and control system,electromagnetic compatibility system,and receiver system.Finally,scientific achievements obtained by FAST during the commissioning phase are also reported.  相似文献   

A Kinematical Calibration of the Galactocentric Distance     

Ming Shen  Zi Zhu Department of Astronomy  Nanjing University  Nanjing   《中国天文和天体物理学报》2007,7(1):120-128

1 INTRODUCTION The distance to the Galactic center R0 is a fundamental constant for astronomy and astrophysics. Most determinations of astronomical quantities are directly connected with the Galactic distance scale, e.g., the rotational speed of our Galax…  相似文献   

The impact of human activities on the flushing properties of a semi-enclosed lagoon: Xiaohai, Hainan, China   总被引：1，自引：0，他引：1  

Gong W  Shen J  Jia J 《Marine environmental research》2008,65(1):62-76

In this study, a Lagrangian particle tracking model driven by hydrodynamic fields was used to investigate the changes of flushing properties in Xiaohai Lagoon resulting from natural evolution and influences of human activities. Comparisons of residence times between 1936 and 2001 indicate that the flushing efficiency of the lagoon has deteriorated greatly during the past seven decades. Over this period, the average residence time of the lagoon has increased from 45 to 71 days, an increase of 59%. The Lagrangian residual velocity has decreased from 1936 to 2001 in the large portions of the lagoon, and the spatial distribution pattern of the residual current has changed significantly. The well-developed horizontal circulations in 1936 disappeared. Instead, the horizontal Lagrangian residual velocity showed uniformly seaward motion with reduced velocity in 2001. Human activities have incurred great impacts on the deterioration of flushing efficiency. The reduction of river inflow imposed the most significant impact, causing an increase of average residence time by 33%. The land reclamation in the lagoon came as the second most significant factor, causing an increase of 15%. Closure of the North Opening had posed minor impact. The model results suggest that restoring the river inflow, as well as the dredging of the tidal channel and the inner lagoon, should be the top proprieties for future water quality management.  相似文献   

Rotation Periods of Nine ROSAT Selected Solar-Type Stars     

Li-Feng Xing Shuang-Yi Zhao Wei Su Yan Shen Xiao-Bin Zhang Jian-Yan Wei 《中国天文和天体物理学报》2007,7(4):551-557

We monitored 16 X-ray selected young solar-type stars for light variation and found appreciable periodic light variability with amplitudes of a few hundredths of a magni-tude in nine of the objects. Using the method of Phase Dispersion Minimization (PDM) and Fourier analysis (software PERIOD04), the rotation periods of these stars were determined from the photometric data. The rotation periods of all nine stars are shorter than about 3days. It is suggested that, as with the Pleiades cluster, small amplitude light variations are quite common among young solar-type stars with rotation periods around 3 days or less. This gives further evidence for the spin up of solar-type stars predicted by models of angular momentum evolution of pre-main sequence stars.  相似文献   

Probabilistic Estimation of Hazard on Engineering Site Based on the Intensity of Historic Earthquakes and A Preliminary Comparison with Seismic Hazard Analysis     

Zhang Jie  Shen JianwenSeismological Bureau of Anhui Province  Hefei  China 《中国地震研究》1995,(1)

This paper introduces a new method to estimate the seismic hazard on engineering site.The method is mainly based on intensity data of historical earthquakes.The obvious feature of the method is to use some ideas of seismic hazard analysis and considering regional seismicity tendency.The authors depict the comprehensive method to estimate the related parameters and predict the seismic hazards for 14 sites as practical examples.Some problems are also discussed.Compared with seismic hazard analysis,this method has certain advantages,such as simpler computation,lower uncertainty and smaller sensitivity factor.Moreover total hazard P(I≥i)of a site can be examined with real historic data.The result given by the method in this paper can be more stable than that given by seismic hazard analysis nowadays.  相似文献   

Establishment of the GPS Crustal Deformation Monitoring Network in North China   总被引：1，自引：0，他引：1  

Li Yanxing  Shen Jianhua  and Wang MinFirst Crustal Deformation Monitoring Center  SSB  Tianjin ChinaDepartment of Scientific Programming  Earthquake Monitoring  SSB. Beijing China 《中国地震研究》1995,(3)

The Global Positioning System (GPS) is a new method to monitor the crustal deformation for earthquake prediction.Now a four-dimensional crustal deformation monitoring network applying GPS techniques has been established in North China,which is an important seismic monitoring area.Results with high precision have been achieved in the first measurement since a series of advanced methods and measures were adopted,and thus a good foundation has been laid for future researches on earthquake prediction and geodynamics.  相似文献   

Cretaceous-Eogene Ostracod Assemblages in Henan and Their Evolutionary Features     

Zhang Shen Jidong Oil Exploration &. Development Corp.  Tanghai  Hebei Fei Zhenbi 《《地质学报》英文版》1995,69(1):99-110

This paper studies a large number of Cretaceous-Eogene ostracod fossils in the Meso-Cenozoic Nanyang, Zhoukou, Rendian, Luoyang, Lingbao, Tantou and Kaifeng basins of Henan. Eight ostracod assemblages have been recognized. This paper discusses their geographical distribution and geological ages as well as their features and evolutional trends. Besides, it also deals with the palaeoclimate under which the various assemblages lived and the significance in petroleum exploration.  相似文献   

APS系列解析测图仪精度分析     

胡Shen 《测绘科技》1993,(1):33-39

  相似文献   

Palinspastic Reconstruction for Tectonics of Northeast China and Its Vicinity     

Liu Xianwen Meng Xiangang Institute of Geomechanics  Chinese Academy of Geological Sciences  Beijing Tamaki Kensaku Ocean Research Institute  University of Tokyo  Tokyo  Japan Shen Ninghua Ge Xiaohong Department of Earth Sciences  Cha 《中国地质大学学报(英文版)》1998,9(3)

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＮｏｒｔｈｅａｓｔＣｈｉｎａａｎｄｉｔｓａｄｊａｃｅｎｔｒｅｇｉｏｎｐｒｅｓｅｎｔａｕｎｉｑｕｅｔｅｃｔｏｎｉｃｐａｔｅｒｎ,ｗｈｉｃｈｉｓｄｉｓｔｉｎｇｕｉｓｈｅｄｂｙｌａｒｇｅｓｃａｌｅＮＥｔｒｅｎｄｉｎｇｇｒａｎｉ...  相似文献   

青岛观象台海尔—波普慧星观测     

孙寿Shen  张春生 《紫金山天文台台刊》1998,17(3):53-57

中国科学院紫金山天文台青岛观象台从1996年4月开始到1995年5月1日结束,在138个观测夜,共拍摄Hale-Bopp彗星底片508张。发现:Hale-Bopp彗星在1996年9月24日的一次爆发,1996年10月26日,11月13日的两次可能爆发。在1996年9月23日的底片上,Hale-Bopp呈现巨大的喷流。在1997年2月8日至5月1日期间,Hale-Bopp彗星彗头内存在大量壳层结构。  相似文献