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基于等方性系数的地形可导航性的方向性研究 被引量:2
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作者 张国忠 沈林成 常文森 《国防科技大学学报》 EI CAS CSCD 2000年第4期102-106,共5页
地形可导航性分析的研究中 ,当飞行器从不同方向进入特定区域时 ,怎样评价该区域提供的可导航性能力一直是地形匹配中的重要问题。本文建立了地形本质特征的数学过程描述———分数布朗运动 ;基于分形几何理论 ,通过分析地形表面的轮廓... 地形可导航性分析的研究中 ,当飞行器从不同方向进入特定区域时 ,怎样评价该区域提供的可导航性能力一直是地形匹配中的重要问题。本文建立了地形本质特征的数学过程描述———分数布朗运动 ;基于分形几何理论 ,通过分析地形表面的轮廓谱矩和表面谱矩的特性 ,提出一种地形特征度量值———等方性系数 ;并且分别得出了等方性好与差时 ,适配区域的匹配概率与方向之间的定性关系 ,有助于提高地形可导航性分析的效率。 展开更多
关键词 地形形貌 分数布朗运动 分形几何 等方性系数 匹配概率
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A 3D evaluation method of cutting surface topography of carbon/carbon(C/C) composite 被引量:1
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作者 周鹏 Zhao Fuling 《High Technology Letters》 EI CAS 2010年第4期366-372,共7页
This paper aims to establish a 3D evaluation method for cutting surface topography of C/C composites. The cutting surface is measured by Talyscan 150, using 3D non-contact measurement. By evaluating 2D and 3D roughnes... This paper aims to establish a 3D evaluation method for cutting surface topography of C/C composites. The cutting surface is measured by Talyscan 150, using 3D non-contact measurement. By evaluating 2D and 3D roughness of C/C composite and Duralumin, the 2D evaluation method of the cutting surface topography of C/C composite loses a lot of information, and the characteristics of the surface topography of C/C composite can be comprehensively and authentically evaluated only by the 3D evaluation method. Furthermore, 3D amplitude and spatial parameters are adopted to evaluate the surface and the results show that: the topography of the C/C composite is anisotropy and there are no obvious feeding textures but abrupt peaks and valleys on surface of the C/C composite, which indicates that the machining mecha- nism is different from that of the metal. In conclusion, The C/C composite surface is evaluated using a 3D evaluation method, the roughness error is small, and the unique topography characteristics earl be au- thentically evaluated. 展开更多
关键词 C/C composite surface topography 3D evaluation method
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Geomorphological Features of Ancient Volcanic Terrain of Mars
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作者 Svetlana Pugacheva Vladislav Shevchenko 《Journal of Environmental Science and Engineering(A)》 2014年第4期204-210,共7页
The article considers geological and morphological features of a volcanic relief of a surface of a planet Mars. Effusive magmatism processes at early stages of planet crust forming come out in structure of solidified ... The article considers geological and morphological features of a volcanic relief of a surface of a planet Mars. Effusive magmatism processes at early stages of planet crust forming come out in structure of solidified relief forms of Mars. Volcanic relief of a planet represents relic ancient line oriented forms, areal and central lava flooding. Linear forms generate shield volcanoes, chains of volcanic mountains and radial-concentric faults. This article deals with geological and morphological characteristics of the volcanic terrain of Mars. Hypsometric altitude profiles of volcanoes have been built based on the MOLA (Mars orbiter laser altimeter) of the spacecraft MGS (Mars global surveyor). The gradient of volcano flanks has been calculated. The relative age of the volcanic terrain was estimated by the classical method of counting of the density of impact craters. Names of the volcanic landforms of Mars are given in the article in accordance with the name nomenclature system approved by the International Astronomical Union. Research results make it possible to compare the scientific and technical information about the planet and analyze the materials of satellite imagery of Mars. 展开更多
关键词 MARS volcanic terrain dry river valleys a great catastrophe on Mars
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