本文讨论了在流行的CAD环境下进行零件和装配件公差分析。介绍了公差分析中的两个重要的分析方法。并用公差分析工具CE/TOL对某一行星减速箱中的一个间隙值进行了公差分析。极限状态分析法给出的结果是最保守的,而统计分析法从概率的角度出发,给出了更现实的结果。
A 1.5 Ma sporopollen record was obtained from a continuous loess-paleosol sequence at Chaona in the central Chinese Loess Plateau. It shows that (1) arid herbs of largely Artemisia and Chenopodiaceae
This paper takes Zhexi hydraulic region in Taihu Basin as a study area. On the basis of hydraulic analysis function of Arcgis8.3, the drainages were delineated by selecting the monitoring points and d
Quantitatively determining the sources of dune sand is one of the problems necessarily and urgently to be solved in aeolian landforms and desertification research. Based on the granulometric data of s
KARST, the Chinese SKA concept, consists of some 30 individual FAST-type elements to be set up in a karst region of Guizhou Province. A crucial question is how to select 30 optimized sites from hundre
根据山地研究现状和相关学科发展,提出山地系统科学概念、科学问题、研究方法,建立山地系统科学的框架.山地系统科学,以地球系统科学理论作为理论指导,以"3S"集成等新方法和技术体系为支撑,从时间序列、空间结构、动态过程和耦合关系等多维度入手,对山地系统的动态过程、演变规律、形成机制、耦合关系等展开全方位的研究.从时间序列上,重点研究不同时期自然及人为作用下山地系统的环境演变与山地资源灾害的时空响应机理
介绍了Unigraphics(UG)软件的主要建模特点,结合利用CAD软件建立标准零件库的一般原则,介绍了几种基于UG建立标准零件库的方法,以及建模需要注意的问题,对利用该软件进行设计的工程人员,有一定的参考意义。
The purpose of this article is to identify the effect of land use pattern on rainfall runoff and runoff sediment relations in Zichang Watershed of the Loess Plateau. From 1986 to 1997, many farmlan