Resonance transitions associated to weak capture in the restricted three-body problem

An interesting dynamics is studied in the restricted three-body problem where a particle abruptly transitions between resonance states, called a resonance hop. It occurs in a region about the secondary mass point which supports weak capture. This region, called a weak stability boundary, was recently proven to give rise to chaotic dynamics. Although it was numerically known that the resonance hop was associated with this boundary, this process was not well understood. In addition, the dynamical structure of the weak stability boundary has not been well understood. In this paper, we give a way to reveal the global structure of the weak stability boundary associated to resonance motions. This structure is shown to be surprisingly rich in resonant periodic motions interconnected by invariant manifolds. In this case, nearly all the motions are approximately resonant in nature where resonance hops can occur. The correlation dimension of orbits undergoing resonant motions, associated to the weak stability boundary, is also examined. The dynamics analyzed in the present paper is related to that studied by J. Marsden et al. under the perspective of Lyapunov orbits and the associated invariant manifolds. Applications are discussed.     

高超声速粘性干扰效应相关性研究

探讨了高超声速粘性干扰效应的相关性理论,采用CFD数值模拟方法对轨道器再 入阶段的粘性干扰效应进行了研究,以此为基础考察了粘性干扰相关参数〖AKν-5〗′ ∞的关联特性。对计算结果的分析表明：〖AKν-5〗′∞能够将轨道器外形气动力 的地面风洞试验数据和飞行试验数据进行有效关联,从而为建立轨道器外形再入气动力天地 换算方法奠定了基础。
     

相关分析法辨识时域离散数学模型的频率特性

本文提出利用经典过程辨识法中的相关分析法,求取时域离散数学模型的频率特性。通过实例验证了此方法的有效性。此法误差小,能满足研究和设计上的要求。它适用于线性系统,也适用于非线性系统。     

固体火箭发动机实际燃速常数的计算

根据试车数据，对全尺寸发机和标准发机瞬时燃速进行了计算，利用参数辨识技术，确定了维也里燃公式（ｒ＝ａｐ＾ｎ）里的常数，计算结果表明：对应用在不同发动机中的同一种推进剂来说，其燃速系数α和压强指数ｎ是不同的。探讨了不同发动机燃速常数变化的原因以及规律性，提供了分析全尺寸发动机，标准发动机之间燃速相关性的新方法。     

发动机性能量与输入量的相关性研究

展开了相关性研究，讨论了一种相关性分析的算法，并在此基础上进行了大量的数字仿真实验，结果表明通过相关性分析不但可减少计算工作量，而且即使在传感器有限的情况下，模型也可很好的跟踪发动机，两者的匹配效果较好     

合成射流流场数值模拟及激励器参数分析

建立了将合成射流激励器腔体、出口喉道及外部受控流场作为单连域计算处理的全流场计算模型———X L模型,并进行了二维数值计算。基于数值计算获得的激励器出口数度分布,对合成射流激励器结构参数及驱动因素对合成射流的影响进行了分析,得到了表示激励器参数和出口最大速度关系的相关函数,为设计强劲且高效率的合成射流激励器提供参考。     

舰载机机身加筋壁板屈曲疲劳试验

舰载机弹射起飞和拦阻着舰的张力场屈曲波在机身壁板上产生附加的拉伸或弯曲应力,从而显著降低结构疲劳强度、改变疲劳破坏部位。以张力场梁形式的三点弯曲试验开展了反复屈曲下的疲劳特性研究。通过疲劳试验测得的临界屈曲载荷与按工程张力场理论得到的临界屈曲载荷对比,吻合较好。根据3级不同载荷水平下的疲劳试验结果,给出了张力场梁屈曲疲劳试件的无量纲载荷比-寿命曲线及载荷比-张力场系数曲线。根据张力场系数与载荷关系、载荷寿命曲线及飞机寿命指标可控制张力场的严酷程度来开展机身壁板轻量化设计。本项工作为舰载机机身壁板在弹射起飞和拦阻着舰过程中的反复屈曲疲劳问题评定积累了数据。     

OBSCA谱相关分析器的实现研究

文章研究了一比特谱相关算法（OBSCA）,简化了相关运算环节,进一步研究了其数字实现方法,并设计了一种OBSCA高效并行实现方案,大大提高了谱相关函数的计算效率。     

扩频信号角跟踪带宽分析与优化

扩频信号由于带宽宽、信噪比低,难以实现对信号的角跟踪。本文在和差信号相关法提取角误差电压的基础上,利用小部分带宽法的一些原理,提出了和差信号小部分带宽相关的方法,提高了输出信噪比。     

Correlation-weighted least squares residual algorithm for RAIM

The Least Squares Residual (LSR) algorithm, one of the classical Receiver Autonomous Integrity Monitoring (RAIM) algorithms for Global Navigation Satellite System (GNSS), presents a high Missed Detection Risk (MDR) for a large-slope faulty satellite and a high False Alarm Risk (FAR) for a small-slope faulty satellite. From the theoretical analysis of the high MDR and FAR cause, the optimal slope is determined, and thereby the optimal test statistic for fault detection is conceived, which can minimize the FAR with the MDR not exceeding its allowable value. To construct a test statistic approximate to the optimal one, the Correlation-Weighted LSR (CW-LSR) algorithm is proposed. The CW-LSR test statistic remains the sum of pseudorange residual squares, but the square for the most potentially faulty satellite, judged by correlation analysis between the pseudorange residual and observation error, is weighted with an optimal-slope-based factor. It does not obey the same distribution but has the same non-central parameter with the optimal test statistic. The superior performance of the CW-LSR algorithm is verified via simulation, both reducing the FAR for a small-slope faulty satellite with the MDR not exceeding its allowable value and reducing the MDR for a large-slope faulty satellite at the expense of FAR addition.