共查询到20条相似文献,搜索用时 31 毫秒
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In this letter, we are trying to resolve the electromagnetic problem for the movements of the superconducting particles of the protoplanetary cloud in the magnetic field of Saturn. The force of levitation (Meissner-Ochsenfeld phenomenon) is introduced to the field of planetary science for the first time. It is shown from our theoretical analysis that rings of Saturn might have a superconducting origin, and rings might levitate within magnetic equator plane of the planet. 相似文献
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《International Journal of Digital Earth》2013,6(1):80-87
Abstract Cultures throughout the world are associating with the rivers. People depend upon the rivers and their tributaries for food, water, transport, and many other aspects of their daily lives. Unfortunately, human beings have not calculated the accurate lengths for the great rivers even today. The lengths of the rivers are very different in popular textbooks, magazines, atlases and encyclopedias, etc. To accurately determine the lengths of the principal rivers of the world, the combination of satellite image analysis and field investigations to the source regions is proposed in this paper. The lengths of the Nile, Amazon, Yangtze, Mississippi, Yellow, Ob, Yenisey, Amur, Congo and Mekong, with lengths over or close to 5000 km, were calculated using the proposed method. The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable. 相似文献
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常同元 《测绘与空间地理信息》2016,(10)
在不动产测量中,计算外墙体一半面积的数学模型,只有针对四边形直角房屋的数学模型,而对于多边形直角房屋计算外墙体一半面积的数学模型还没有发现,这给分析多边形直角房屋外墙体一半面积的精度带来困难,本文通过研究分析,推导出了多边形直角房屋外墙体一半面积的数学模型,供研究面积精度者参考。 相似文献
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当目标面与像片平面不平行时,圆形标志的像将为椭圆,椭圆的中心与标志中心的像存在偏差。当标志较大时,此偏差将显著影响求解的精度。揭示了偏差的方向性,导出了求解偏差的方程,给出了偏差的解算步骤 相似文献
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本文主要阐述经典的最小二乘间接平差和秩亏自由网平差的基准,并据此讨论秩亏自由网平差的实际应用。 相似文献
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对流层是影响GNSS信号传播的主要因素之一。利用中国境内及周边IGS站URUMLHAZ(乌鲁木齐-拉萨)、BJFS-PIMO(北京房山-菲律宾)的南北基线和URUM-BJFS(乌鲁木齐-北京房山)、BJFS-DAEJ(北京房山-韩国)的东西基线数据,分别计算其对流层改正前后基线长,总结改正前后基线变化规律,分析对流层改正时影响基线长波动的因素,对探究对流层对基线影响及改进GNSS定位精度具参考意义。 相似文献
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Demosthenes C. Christodoulidis 《Journal of Geodesy》1979,53(1):61-77
Seasonal and latitude dependent corrections to the gravity and height anomalies are developed in order to account for the
neglect of the atmospheric masses outside the geold, when using Stokes’ equation. It is shown that the atmospheric correction
to gravity at sea level is almost constant, equal to0.871 mgals with a variation of2 μ gals whereas the height anomaly correction varies between −0.1 cm and −1.3 cm. Further, when the combined latitudinal/seasonal dependence is neglected in the atmospheric corrections, the maximum error
introduced is of the order of40 μ gals for the gravity corrections and0.7 cm for the height anomaly corrections. 相似文献
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刘玉成 《测绘与空间地理信息》2003,26(1)
各位领导、各位来宾:在这北国冰封万里雪飘的季节里,我们欢聚一堂,在此庆祝《东北测绘》创刊25周年,出刊100期。我受省科技厅、省科技期刊编辑学会的委托前来参加会议,谨代表黑龙江省科技厅和省科技期刊编辑学会向《东北测绘》的主管、主办单位和《东北测绘》编委会及编辑部的同志们表示衷心地祝贺,向全国各地前来参加此次庆祝活动的领导、专家和学者们表示热烈地欢迎和诚挚地谢意。《东北测绘》的前身是《黑龙江测绘》,是由黑龙江测绘局主管,黑龙江省测绘学会主办的技术性期刊。她创刊25年来,始终遵循“宣传、贯彻党和国家有关测绘科技的方… 相似文献
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论真误差拟准解的基本特性 总被引:6,自引:0,他引:6
本文将回答这样一个问题:为什么拟准检定法能准确地定位粗差并估计出粗差大小?首先从理论上论证真误差的估值的重要特性:真误差拟准解的大小完全由它对应的观测值中的粗差决定,因此它能直接反映粗差的位置和大小。本文还用算例验证了这一结论。 相似文献