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911.
简要地介绍了CARIA校准箱的基本构成和应用,并给出了该校准箱和荷兰NLR校准箱的一些比较。在这个校准箱中、推力和流量的测量精确度可分别达到0.2%和0.3%。 相似文献
912.
Sketching is traditionally associated withdoodling simple strokes on a piece of paper.Only few professionals outside of design andthe fine arts have recognized the expressivepower of this intuitive modality. However,sketching seems particularly well suited tocapture objects and situations in a spatialenvironment, such as geographic space. To learnmore about the techniques and strategies peopleuse when sketching, a survey of sketching wasconducted. The study showed that paper andpencil sketches contain mostly simple andabstract objects that are composed of only fewstrokes. The spatial configuration of a sceneis primarily expressed through the topologicalordering of objects relative to each other.Metric relationships are used to refine spatialconfigurations. These and other findingssuggest that sketching is an appropriatemodality to interact with a computer where onewants to describe and capture objectconfigurations in a spatial environment, suchas a geographic information system (GIS). 相似文献
913.
XP方法测试驱动和多版本发布的实践,决定了软件产品集成测试也是一个增量迭代的过程。用户使用测试对提高产品的可靠性有重要作用。本文探讨XP测试过程对软件缺陷的影响及其缺陷改正效率的度量。 相似文献
914.
介绍了一种用VXI总线技术组建的机载火控系统远程测试装置 ,以及该装置的硬件配置和在LabWindows/CVI环境下的软件模块化设计 相似文献
915.
高频角振动台中某些特殊问题的研究 总被引:2,自引:0,他引:2
以最近研制成功的一种高频角振动台为例,详细阐述了这种台子的执行元件、驱动电路和控制系统的特殊问题和解决方法。提出了可供实用的陀螺测试方法。 相似文献
916.
917.
《中国航空学报》2022,35(9):314-332
An accurate and reliable turbofan engine model which can describe its dynamic behavior within the full flight envelop and lifecycle plays a critical role in performance optimization, controller design and fault diagnosis. However, due to the performance differences caused by the tolerance of engine manufacturing and assembly, and performance degradation during continuously stringent environmental regulations, the model accuracy is severely reduced. In this paper, an adaptive modification method of turbofan engine nonlinear Component-Llevel Model (CLM) based on Long Short-Term Memory (LSTM) Neural Network (NN) and hybrid optimization algorithm is pro-posed. First, a dynamic compensator with a combined LSTM NN architecture is constructed to compensate for the initial error between the experimental data and CLM of a turbofan engine under health condition. Then, a sensitivity analysis approach based on the entropy coefficient and technique for order preference by similarity to an ideal solution integrated evaluation is developed to choose the unmeasurable health parameters to be adjusted. Finally, a parallel hybrid optimization algorithm is developed to complete the adaptive model modification when the performance degrades. The proposed method is verified on a military low-bypass twin-spool turbofan engine, and the experimental results show the effectiveness of the proposed method. 相似文献
918.
对MB8变形镁合金超声疲劳试样进行设计计算.为了减小试样振幅,使试样产生较少的热量,减轻冷却系统压力的同时防止试样产生相变等组织变化,将试样设计成变截面形状.根据试样振动位移方程、边界条件和位移连续条件推导出试样谐振长度与其他尺寸的关系,计算出一系列超声疲劳试样的尺寸.结果表明:变截面圆柱和板状试样随着圆弧过渡段长度增大,谐振长度减小,圆弧过渡半径增大;对于无中间等截面段试样,位移应力系数Cs和应力放大系数M随着圆弧过渡段长度减小而减小;对于含有中间等截面段试样,位移应力系数Cs和应力放大系数M随着中间等截面段长度减小而减小. 相似文献
919.
Daniele Bortoluzzi John W. Conklin Carlo Zanoni 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
In the LISA Pathfinder mission, the grabbing positioning and release mechanism will perform a critical phase, which is the injection of a test mass into a perfect free-fall condition (also called geodesic trajectory). A possible failure is the test mass remaining adhered to the mechanism or released with an excessive velocity, which would hinder the subsequent capacitive control to the desired geodesic status. 相似文献
920.