多星混合资料的定轨     

王歆 《天文学报》2014,(6)

在空间目标光学观测资料定轨中常常会遇到多个目标的观测被标记为同一个目标的情况,由于包含了多个目标的数据,定轨过程无法收敛或者完全错误.从极大似然估计角度,采用EM(Expectation Maximum)方法提出一种将轨道改进和识别过程相互融合的处理方法,并在具体实现过程中给出一种稳健估计方法.数值模拟表明方法简便、有效、可行.采用站间差历元差的手段,对当前电离层变化值进行求解与预测,可以将电离层延时误差的变化控制在一定范围,满足频率传递的要求.  相似文献   

A new lunar absolute control point: established by images from the landing camera on Chang'e-3     

Fen-Fei Wang  Jian-Jun Liu  Chun-Lai Li  Xin Ren  Ling-Li Mu  Wei Yan  Wen-Rui Wang  Jing-Tao Xiao  Xu Tan  Xiao-Xia Zhang  Xiao-Duan Zou  Xing-Ye Gao 《中国天文和天体物理学报》2014,(12)

The establishment of a lunar control network is one of the core tasks in selenodesy, in which defining an absolute control point on the Moon is the most important step. However, up to now, the number of absolute control points has been very sparse. These absolute control points have mainly been lunar laser ranging retroreflectors, whose geographical location can be observed by observations on Earth and also identified in high resolution lunar satellite images. The Chang'e-3(CE-3) probe successfully landed on the Moon, and its geographical location has been monitored by an observing station on Earth. Since its positional accuracy is expected to reach the meter level, the CE-3 landing site can become a new high precision absolute control point. We use a sequence of images taken from the landing camera, as well as satellite images taken by CE-1 and CE-2, to identify the location of the CE-3 lander. With its geographical location known, the CE-3 landing site can be established as a new absolute control point, which will effectively expand the current area of the lunar absolute control network by 22%, and can greatly facilitate future research in the field of lunar surveying and mapping, as well as selenodesy.  相似文献   

Data processing and initial results from the CE-3 Extreme Ultraviolet Camera     

Jian-Qing Feng  Jian-Jun Liu  Fei He  Wei Yan  Xin Ren  Xu Tan  Ling-Ping He  Bo Chen  Wei Zuo  Wei-Bin Wen  Yan Su  Yong-Liao Zou  Chun-Lai Li 《中国天文和天体物理学报》2014,(12)

The Extreme Ultraviolet Camera(EUVC) onboard the Chang'e-3(CE-3)lander is used to observe the structure and dynamics of Earth's plasmasphere from the Moon. By detecting the resonance line emission of helium ions(He+) at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius(RE) in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plasmasphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.  相似文献   

Pb distribution and translocation in Jiaozhou Bay     

杨东方  苏畅  高振会  孙培艳  曹丽歆 《中国海洋湖沼学报》2008,26(3):296-299

The trends of distribution, translocation and seasonal change of heavy metal Pb were studied based on the surface and bottom water sampling in Jiaozhou Bay in 1979, and compared with those in 1990＇s. The results showed that the source of Pb in the bay was from wastewater and sewage in the east of Jiaozhou Bay from ocean vessels. Pb concentration was higher in spring and lower in summer and autumn, and remained stable through sedimentation in the bottom layer. The overall water quality was good in 1970＇s. Compared with the environmental monitoring data of 1995-1999, Pb pollution had become serious. Therefore, more efforts should be made to protect the bay from Pb pollution.  相似文献   

Effect of germanium dioxide on growth of Spirulina platensis     

Cao Ji-xiang 《中国海洋湖沼学报》1996,14(4):378-386

This study on the effect of different concentrations of germanium dioxide (GeO₂) on the specific growth rate (SGR), pigment contents, protein content and amino acid composition ofSpirulina platensis showed that Ge was not the essential element of this alga; that GeO₂ could speed up growth and raise protein content ofS. platensis, and could possibly influence the photosynthesis system. The concentration range of GeO₂ beneficial to growth ofS. platensis is from 5–100mg/l. GeO₂ is proposed to be utilized to remove contamination byChlorella spp. usually occurring in the cultivation ofSpirulina.  相似文献   

走向Internet网际     

季凯帆  宋谦  曹文达 《天文研究与技术》1995,(3)

从１９９５年３月１３日开始，我们开始与中国科学院网络中心和昆明电信局通信处联系，准备建立云南天文台Ｅｍａｉｌ系统。到３月２１日本系统技术上已基本调试完成。本文介绍了这一系统的建立过程和通过这一系统可以得到的网络资源。  相似文献   

激光时间传递技术的进展   总被引：4，自引：0，他引：4  

李鑫  杨福民 《天文学进展》2004,22(1):10-22

激光时间传递技术是通过激光脉冲在空间的传播来实现地面与卫星时钟或地球上远距离两地时钟的同步，它具有很高的准确度和稳定度。一些国家已经成功进行了激光时间传递的试验，结果证明利用激光进行时钟之间的同步是有效可行的。介绍国内外已有的激光时间传递试验的情况和结果，重点介绍美国地面与机载原子钟之间的激光时间比对，以及法国的LASSO(LAser Synchronization from Stationary Orbit)和T2L2(Time Transfer by Laser Link)计划。  相似文献   

.Net环境下空间数据缓存方案的设计与实现     

李滨  侯小牛  常德海  陈欣 《海洋测绘》2009,29(3):34-37

空间数据查询效率的优劣决定着三层体系结构空间信息系统的应用效果。空间数据缓存技术是提高空间数据查询效率的有效方法之一。在数据缓存技术逐渐成熟的今天，如何利用数据缓存技术来构建空间数据缓存是目前研究的热点。基于Microsoft新的数据缓存技术，借助常用的格网索引，在客户端和应用服务器端开辟空间数据缓存区，以降低数据的传输量，减少用户的请求响应时间，从而提高空间数据查询效率。在利用版本控制技术实现空间数据缓存的同时，解决客户端、应用服务器和数据库服务器的数据一致性问题，确保空间数据的有效性和可用性。  相似文献   

对广东省高校教师工资统发工作的思考     

徐英起  黄欣  黄雪洪 《广东海洋大学学报》2002,22(2):93-96

分析了广东省高校教师工资统发过程中存在统发工资与地方保险局扣缴的养老金无法达到一致、统发工资与地方税务局扣缴的个人所得税的起征标准不一致、后勤改革与工资统发尚不配套、人事分配制度改革与统发工资尚不配套等问题 ,提出了解决问题的建议与对策  相似文献   

A Catalog of Luminous Infrared Galaxies in the IRAS Survey and Second Data Release of SDSS     

Chen Cao  Hong Wu  Jian-Ling Wang  Cai-Na Hao  Zu-Gan Deng  Xiao-Yang Xia  Zhen-Long Zou National Astronomical Observatories  Chinese Academy of Sciences  Beijing  Graduate School of Chinese Academy of Sciences  Beijing College of Physical Sciences  Graduate School of Chinese Academy of Sciences  Beijing Department of Physics  Tianjin Normal University  Tianjin 《中国天文和天体物理学报》2006,6(2):197-209

We selected a sample of luminous infrared galaxies by cross-identification of the Faint Source Catalogue (FSC) and Point Source Catalogue (PSC) of the IRAS Survey with the Second Data Release of the SDSS. The size of our sample is 1267 for FSC and 427 for PSC by using the 2σ significance level cross-section. The "likelihood ratio" method is used to estimate the individual's reliability and for defining two more reliable subsamples (908 for FSC and 356 for PSC). A catalog of infrared, optical and radio data is compiled and will be used in further work. Some statistical results show that luminous infrared galaxies are quite different from ultra-luminous infrared galaxies. The AGN fractions of galaxies at different infrared luminosities and the radio-infrared correlations are consistent with the previous studies.  相似文献