Conceptual design and flight test of two wingtip-docked multi-body aircraft

To overcome the drawbacks such as large wing deformations, poor performance encountering gusts, limits in taking off and landing, inconvenience of transportation of High-Altitude Long-Endurance (HALE) Unmanned Aerial Vehicles (UAVs), a new conceptual aircraft called wingtip-docked Multi-Body Aircraft (MBA) has attracted lots of attentions. Aiming to investigate the feasibility of this concept, two UAV models were designed, manufactured and connected by a wingtip-docking mechanism, which only allows the relative roll motion between the two aircraft. The trim solution of the two connected aircraft is firstly obtained by solving the developed nonlinear flight dynamic equations, followed by the stability analysis based on the linearized model. The results show that the connected aircraft is inherently unstable and cannot fly without a reasonable flight control system. A set of Proportional-Integral-Derivative (PID) control laws was then developed and implemented in the two experimental aircraft. The success of the flight tests show that the flight control can effectively eliminate the unstable motion and the wingtip-docked MBA is controllable and feasible.     

迎角过载边界限制器的设计方法

介绍了迎角过载边界限制器的意义、设计要求和一些有代表性的国内外飞机的边界限制器设计方法。边界限制经历了硬限制、软限制、反馈限制和比较逻辑反馈限制几个阶段。分析了这些设计方法的优缺点,并对比较逻辑反馈限制器的设计方法进了理论推导,提出了这类边界限制器重要参数的确定方法。     

边缘检测技术在火箭发动机实验诊断中的应用

对高速运动分析仪拍摄的Ｕ型燃气发生器固体装药燃烧和双组元液体喷嘴雾化图像进行了边缘检测图像分析,根据被分析实物边缘层次性较强的特点,在简单边缘检测的基础上采用自动门限、二次门限和最佳滤波的方法,获得了固体燃气发生器在燃烧过程中的内部结构、推进剂瞬态燃速、绝热隔板烧蚀率等参数,获得了双组元液体喷嘴的雾化角、粒子分布等特性。     

深空探测对航天器热控技术的推动

工程热物理学广泛应用于航天领域,一方面解决了具体航天工程问题,另一方面逐步发展成为交叉学科——空间热物理。随着我国在深空探测领域不断拓展,以深空探测器研制中的工程热物理问题为需求背景,推动着航天器热控制技术、防热技术等取得新的发展。文章在介绍深空探测器技术体系的基础上,分析了热设计、热分析、热试验、热控硬件、防热等方面的技术进步,并就深空探测领域进一步拓展对工程热物理发展的牵引进行了展望,分析了工程热物理学与航天技术间相互促进、相互推动的关系。     

国内氰酸酯树脂增韧改性新技术研究进展

从增韧改性CE角度出发,介绍了近几年增韧改性氰酸酯树脂的方法,包括纳米粒子(SiO2、SiC)改性、笼型倍半硅氧烷(POSS)改性、热固性树脂(EP、BMI)改性、热塑性树脂改性及其他改性方法,并且着重阐述了增韧机理..     

Ionospheric electron density over Resolute Bay according to E-CHAIM model and RISR radar measurements

In this study, predictions of the E-CHAIM ionospheric model are compared with measurements by the incoherent scatter radars RISR at Resolute Bay, Canada, in the northern polar cap. Reasonable coverage was available for all seasons except winter for which no conclusions were drawn. It is shown that ratios of the model-to measured electron densities are close to unity in the central part of the F layer, around its peak. This is particularly evident for summer daytime. Distributions of the ratios are wider for other seasons indicating larger number of cases when the model underestimates or overestimates. E-CHAIM underestimates the electron density at ionospheric topside and bottomside by ～ 10–20 %. At the bottomside, the underestimations are strongest in summer and equinoctial nighttime. At the topside, the underestimations are strongest in autumn nighttime. Model overestimations are noticeable in the middle part of the F layer during dawn hours in autumn. Overall, the model tends to not predict highest-observed peak electron densities and the largest-observed heights of the peak.     

论袁世凯小站练兵背后的保荐者

西法练兵,是甲午战后晚清朝廷上下的一致呼声,袁世凯顺应历史潮流成为改练新军的倡议者和支持者,凭借自己的才能、经历、政治关系,以及不懈的奔走和钻营,终于取得了督练新军的大权。然促成这一事者,当数刘坤一、李鸿藻、荣禄三人出力最多,之所以举荐袁世凯是基于其各自不同的政治立场和目的,但这一事实无疑是顺应当时的发展趋势的,具有一定的进步意义。     

基于产业支撑的社会主义新农村建设研究

建设社会主义新农村是我国现代化进程中全党工作的重中之重,是全面解决“三农问题”的切入点,是实行工业反哺农业、城市支持农村的落脚点。要实现这一宏伟的目标与历史重任,必须重视农业、农村和农民问题,完成三大战略转变：一是农业的产业化转变,二是农村社会向现代社会形态的转型,三是农民向产业工人及市民的转变。     

国外燃烧诊断技术的新进展

对近十几年来国外燃烧流场参数的非接触式激光光学诊断技术的进展作了简要回顾和评述。     

新型航天器太阳电池阵基板的质量控制

影响新型航天器太阳电池阵基板的质量因素较多,且很复杂。文章着重介绍了基板的质量控制内容,还对一些突出的质量问题作了简述。