排序方式: 共有43条查询结果,搜索用时 0 毫秒
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缓冲性能是气垫式起落系统的一个重要功能,基于以某型地效飞行器为背景的气垫式起落系统方案设计,建立了气垫式起落系统落震仿真模型.利用有限元理论和LS-DYNA仿真平台对气垫式起落系统缓冲性能进行仿真分析.结果表明气垫式起落系统在落震过程中未出现反弹,气囊最大压缩位移为1.015 m,小于允许最大压缩位移1.502 m;整个落震过程出现的最大过载为2.87 g,小于允许最大过载3 g.验证了气垫式起落系统在落震过程中缓冲行程及缓冲性能满足要求. 相似文献
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L. Habash Krause A. Franz A. Stevenson 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
This paper presents an overview of the mathematical foundations for techniques in Exploratory Data Analysis (EDA) for the purpose of investigating the relationships among the numerous variables in large sets of multivariate space weather data. Specifically, we cover techniques in Principal Components Analysis (PCA) and Common Factor Analysis (CFA). These techniques are illustrated using space weather activity indices collected during the year 2002 and the corresponding noon-time hmF2 data from the International Reference Ionosphere (IRI). A CFA is used to categorize the activity indices, and a PCA is used to derive two macro-indices of activity to ascertain the strength of solar and geomagnetic activity. These macro-indices are then used to compare and contrast IRI’s noon-time hmF2 values at six different geographic stations. It was found that the correlation between hmF2 and the macro-indices more accurately represented the variation of this correlation with latitude found in previous studies than if we used an isolated conventional index, such as SSN and AE. We also found that the daily maximum value of the Polar Cap Index was dependent on both solar and geomagnetic activity, but the closely-related cross-Polar Cap Potential was solely associated with elevated levels of geomagnetic activity, which is a unique result compared to previous studies. We argue that the discrepancy can be explained by the difference in experiment designs between the two studies. This paper demonstrates the usefulness of EDA in space weather studies of large multivariate data sets. 相似文献
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简要分析了传统桥式RTD传感器接口电路所存在的固有缺陷,并提出了几种在高精度采集系统中可以使用的接口方法,也指出了各种方法的优缺点。 相似文献
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介绍了两坐标警戒雷达录取终端中模拟器的设计.该模拟器对雷达真实回波进行模拟仿真,包括运动目标模拟、噪声/杂波模拟等,重点描述运动目标与噪声/杂波的生成模型与软/硬件设计.通过该模拟器可以有效检验两坐标警戒雷达的多目标检测跟踪性能与检测方式,具有一定参考价值. 相似文献
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为了对比空间站和导航卫星共视的性能差异,深入分析影响共视性能的主要误差源特征,推进共视技术进一步发展,以对共视时间比对基本原理的分析为基础,从系统设计和关键误差源影响两个方面对比分析空间站和导航卫星共视的差异。理论研究结果表明,不同于导航卫星共视,轨道误差是影响空间站共视精度进一步提升的主要因素;此外,空间站共视还需考虑地球引力时延等精细误差的影响。最后,设计并实施了仿真实验和实测实验,通过实验数据进一步对比两者的性能差异。实验结果表明空间站和导航卫星共视各有利弊,虽然空间站共视的服务区域和连续性逊于导航卫星共视,但可以实现的共视精度至少比导航卫星高一个数量级。 相似文献
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The common design of serial civil aircraft, an important strategy of modern civil aircraft research and develop-ment, minimizes the whole life cycle cost of civil aircraft through asset reuse and resource sharing. However, the existing estimating model for the R&D cost of civil aircraft ignores the effects of common design, so the value estimated by estimating derivative models is significantly inconsistent with the actual one. To solve this problem, a novel assessment method for civil aircr... 相似文献
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