共查询到20条相似文献,搜索用时 375 毫秒
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根据傅科第一类回转仪的设想模型,本文用分析力学的方法研究了单自由度陀螺寻北仪的定向原理,分析了陀螺轴的运动规律,建立了多种因素如陀螺力矩,常阻尼力矩和空气阻尼等影响下的运动微分方程,分别求出对应解,并用小扰动理论研究了稳定性。 相似文献
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为了在西部大开发中更好地为四川的经济的发展提供测绘保障,四川省测绘局决定重新编制《四川省地图集》。本文从几个方面探讨了新版《四川省地图集》的编制,主要包括编制背景,如何选择使用现势性资料,出版方式,装帧设计,结构设计,重点探讨了各图组内容表示的设计。 相似文献
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《测量评论》2013,45(18):241-242
AbstractIn working out vertical heights on the Akuse-Kete Krachi chain of triangulation in the Gold Coast a fairly considerable difference was found between values of the coefficient of refraction obtained from observations taken during the day and those taken at night, the mean values being 0.069 for daylight observations to heliographs and 0.087 for night observations to lamps. This difference no doubt is due mainly to the condition of the atmosphere during the day differing from its condition during the night rather than to any effect due to different sources of light. A new chain has recently been observed in Western Ashanti, and the index of refraction for the daylight observations again gave a lower value than that obtained from the night observations, the figures being 0.073 and 0.099 respectively. For the night work three different sources of light were used, hurricane lamps for short lines, Tilley vapour-pressure lamps for lines of intermediate length, and McCaw acetylene signalling lamps by Watts for long lines. It occurred, therefore, to the writer to examine the results to see if the mean values of the index of refraction showed any variations for the different light sources, since it seemed reasonable to suppose that the constitution of the light emitted from each source would be different and hence that the coefficient of refraction might vary. 相似文献
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Ye. V. Fadeyeva 《地理信息系统科学与遥感》2013,50(1):19-23
A method is proposed for the calculation, based on the Goudriaan model, of estimates of various combinations of spectral radiance coefficients Pi which are optimal for interpretation of soil color and moisture, vegetation cover density, above-ground reserves of phytomass, and color and orientation of phytoelements. These estimates correspond rather closely with actual measurements obtained from the field. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1986, No. 4, pp. 75-79. 相似文献
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Two general approaches for compiling maps of components of the water-ice budget in regions of glacier nourishment are compared and the resulting maps are analyzed. The compilation of raw data is based on field measurements rather than remote sensing information. Translated by Edward Torrey, Alexandria, VA 22308 from: Materialy glyatsiologicheskikh issledovaniy, 1991, No. 72, pp. 94-102. 相似文献
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本文对只在陀螺力矩作用下傅科第一类回转仪的运动规律进行了扰动级数分析,推导了其运动周期公式,并与其线性解进行了比较,同时用动能法分析了该系统的稳定性. 相似文献
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《测量评论》2013,45(38):480-481
AbstractIn a letter published in a recent issue of Nature, Prof. L. F. Bates and Mr J. C. Wilson, of University College, Nottingham, have described a new and novel method of determining the coefficient of thermal expansion of invar. Although this method is hardly likely to be applied to the measurement of the coefficient of expansion of long invar tapes, such as are used by surveyors, yet it is so novel and ingenious in itself that a short reference to it may not be out of place in this Review. One extremely interesting thing about it is that no measurements of a length, or of changes of length, are involved. 相似文献
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本文首先概述了国外大地网平差的现状和我国1954年北京坐标系局部平差及1980年国家大地坐标系整体平差情况,然后论述了我国天文大地网重新平差的必要性,最后,提出了重新平差的初步设想和建议。 相似文献
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A. Y. Levintanus 《地理信息系统科学与遥感》2013,50(1):83-84
The author describes the contents and participation of former Soviet republics in the compilation of a global atlas of desertification, published under the auspices of the United Nations. Translated by H. L. Haslett, Leamington Spa, UK, from: Izvestiya Akademii Nauk SSSR, seriya geograficheskaya, 1991, No. 6, p. 130. 相似文献
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IGS精密钟差精度分析 总被引:1,自引:0,他引:1
对比了IGS官方提供的5 min和30 s间隔的精密钟差变化规律,分析了利用8阶滑动式Lagrange多项式插值和线性插值将精密钟差内插至30 s间隔的精度及可行性,得出了一些国内文献未论及的结论。 相似文献
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