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11.
深层搅拌法技术及其工程应用 总被引:1,自引:0,他引:1
深层搅拌技术是对软土地基进行处理的较常用技术 ,它具有加固效果显著、形式灵活多样、环境无污染、施工机具简单、施工速度快、节省投资等优点 ,目前在地基处理和基坑工程中广泛采用。本文主要阐述该技术特点及在地基处理工程中的应用 ,对同类工程设计具有重要的参考价值。 相似文献
12.
高空高速无人飞行器热控制系统设计 总被引:1,自引:0,他引:1
针对飞行时间短、速度和高度变化快、表面温度波动大的无人飞行器UAV(Unmanned Aerial Vehicles)热控制系统设计难题,提出了一种可解决实际工程问题的热分析计算方法.即把热天工况、冷天工况和标准天工况作为设计/试验工况;采用参考温度法、高超音速工程预测法或计算流体动力学CFD(Computational Fluid Dynamics)数值模拟法,确定了飞行器表面温度分布,并把其作为后续热分析数学模型的外边界条件;分析结构热容量对瞬态热载荷的影响,建立与之相应的边值问题方程,并采用有限差分法求解;根据高空高速飞行特点及瞬态热载荷值,确定仪器设备舱调温系统方案. 相似文献
13.
The rising demand for Unmanned Aerial Systems(UASs) to perform tasks in hostile environments has emphasized the need for their simulation models for the preliminary evaluations of their missions. The efficiency of the UAS model is directly related to its capacity to estimate its flight dynamics with minimum computational resources. The literature describes several techniques to estimate accurate aircraft flight dynamics. Most of them are based on system identification. This paper presents an alternative methodology to obtain complete model of the S4 and S45 unmanned aerial systems. The UAS-S4 and the UAS-S45 models were divided into four sub-models, each corresponding to a specific discipline: aerodynamics, propulsion, mass and inertia, and actuator. The‘‘aerodynamic" sub-model was built using the Fderivatives in-house code, which is an improvement of the classical DATCOM procedure. The ‘‘propulsion" sub-model was obtained by coupling a two-stroke engine model based on the ideal Otto cycle and a Blade Element Theory(BET) analysis of the propeller. The ‘‘mass and the inertia" sub-model was designed utilizing the Raymer and DATCOM methodologies. A sub-model of an actuator using servomotor characteristics was employed to complete the model. The total model was then checked by validation of each submodel with numerical and experimental data. The results indicate that the obtained model was accurate and could be used to design a flight simulator. 相似文献
14.
Mikhail Sachkov Boris Shustov Ana Ines Gómez de Castro 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
During last three decades, astronomers have enjoyed continuous access to the 100–300 nm ultraviolet (UV) spectral range where the resonance transitions of the most abundant atoms and ions (at temperatures between 3000 and 300 000 K) reside. This UV range is not accessible from ground-based facilities. The successful International Ultraviolet Explorer (IUE) observatory, the Russian ASTRON mission and successor instruments such as the Galaxy Evolution Explorer (GALEX) mission or the COS and STIS spectrographs on-board the Hubble Space Telescope (HST) prove the major impact of observations in the UV wavelength range in modern astronomy. Future access to space-based observatories is expected to be very limited. For the next decade, the post-HST era, the World Space Observatory – Ultraviolet (WSO–UV) will be the only 2-m class UV telescope with capabilities similar to the HST. WSO–UV will be equipped with instruments for imaging and spectroscopy and it will be a facility dedicated, full-time, to UV astronomy. In this article, we briefly outline the current status of the WSO–UV mission and the science management plan. 相似文献
15.
This paper presents the novel use of the particle swarm optimization(PSO)to generate the end-to-end trajectory for hypersonic reentry vehicles in a quite simple formulation.The velocitydependent bank angle profile is developed to reduce the search space of unknown parameters based on the constrained PSO algorithm.The path constraints are enforced by setting the fitness function to be infinite on condition that the particles violate the maximum allowable values.The PSO algorithm also provides a much easier means to satisfy the terminal conditions by adding penalty terms to the fitness function.Furthermore,the approximate reentry landing footprint is fast constructed by incorporating an interpolation model into the standardized bank angle profiles.Numerical simulations demonstrate that the PSO method is a feasible and flexible tool to generate the end-to-end trajectory and landing footprint for hypersonic reentry vehicles. 相似文献
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宫自强 《北华航天工业学院学报》2013,23(1):10-14
本文探讨如何通过地源热泵技术实现建筑节能。研究通过地源热泵来实现一机多用,使其既能用于冬季供暖,又可以用于夏季制冷。同时也讨论了如何与太阳能相配合,来实现地热平衡。文中还给出了通过插值法和曲线拟合法对测量数据进行处理获得变温带和增温带的温度-深度曲线的方法。 相似文献
19.
描述电子对抗有效载荷地面测试系统的设计内容,介绍了测试系统的主要组成、功能及测试工作原理,常有的测试项目、测试方法,载荷的数据整理、评估与分析等,为以后电子对抗载荷地面系统搭建提供参考借鉴作用。 相似文献
20.
在程序管制模拟练习中,存在着塔台管制服务、进近管制服务和区域管制服务互不衔接,不能系统地模拟整个管制过程的问题。针对这一情况提出了程序管制一体化模拟练习和程序和管制一体化模拟机的结构设计。 相似文献