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变光天体之回光测距
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作者 赵君亮 《科学》 北大核心 2013年第6期26-29,共4页
利用变光天体的回光效应测定辐射源距离的思想,至今仅有30多年的历史,它为天体距离的绝对测定提供了一条独立的途径,并已就个别银河系和近距河外星系中的变星测距取得了颇有价值的结果。
关键词 变光天体 变星 回光测距 造父变星 活动星系核 超新星
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Combined Method of Datum Transformation Between Different Coordinate Systems 被引量:4
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作者 王晓妮 张洁 《Geo-Spatial Information Science》 2002年第4期5-9,共5页
The similarity transformation model between different coordinate systems is not accurate enough to describe the discrepancy of them.Therefore,the coordinate transformation from the coordinate frame with poor accuracy ... The similarity transformation model between different coordinate systems is not accurate enough to describe the discrepancy of them.Therefore,the coordinate transformation from the coordinate frame with poor accuracy to that with high accuracy cannot guarantee a high precision of transformation.In this paper,a combined method of similarity transformation and regressive approximating is presented.The local error accumulation and distortion are taken into consideration and the precision of coordinate system is improved by using the recommended method 展开更多
关键词 coordinate transformation similarity transformation regressive approximating
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Some Suggestions Improving Apollo Lunar Laser Retroreflector Arrays 被引量:1
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作者 LIU Jiyu 《Geo-Spatial Information Science》 2007年第1期1-3,共3页
According to our engineering research on satellite-borne laser retroreflector array, some suggestions are proposed on how to manufacture a new Apollo LLRA that can make us measure one illuminating point and unillumina... According to our engineering research on satellite-borne laser retroreflector array, some suggestions are proposed on how to manufacture a new Apollo LLRA that can make us measure one illuminating point and unilluminating area on the moon's surface. These suggestions are: to control the dihedral angle offset within ± 0.1″; to use the larger aperture of the transparent face of cube corner prisms; to investigate how to separate out Apollo's reflected laser from mixed beam hitting on the LLR system. 展开更多
关键词 lunar laser retroreflector array cube corner prism dihedral angle offset lunar laser ranging
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