基于自适应网格的钝头体激波诱导燃烧现象数值模拟研究

钝头体激波诱导燃烧是爆震研究的一个基本问题。针对化学恰当量比的H2/Air预混气在Ma=4.79和Ma=6.46时的激波诱导燃烧现象开展数值模拟研究，采用基于有限体积法的块结构自适应网格加密程序AMROC对带化学反应源项的轴对称Euler方程解耦求解，考察了数值模拟中不同形式的MUSCL重构格式、限制器类型以及化学反应机理等重要因素对模拟结果的影响。结果表明，程序能够根据设定的加密判据较好地实现网格自适应加密，减小总网格量，实现高效数值模拟。通过与实验数据的对比，表明非定常激波诱导燃烧算例的准确程度不仅取决于化学反应机理，也取决于限制器类型，而采用两种不同形式的MUSCL重构格式获得的振荡频率则几乎一致，与试验结果的误差分别为1.17%和0.97%。模拟对比经典的Jachimowski机理和近年来新发展的几种包含压力相关反应步的氢/氧反应机理，模拟结果表明：对于Ma=4.79时的非定常激波诱导燃烧模拟，经典的Jachimowski机理仍然是能够给出与实验结果最接近的反应机理；而对于Ma=6.46时的定常激波诱导燃烧模拟，几种反应机理均能给出与实验吻合较好的结果。     

基于等效电路模型与CDKF的锂离子电池荷电状态(SOC)估计

锂离子电池在社会生产各领域应用广泛,由于其复杂的电化学系统,状态检测难度较大,给供电保障带来不利影响.结合Thevenin等效电路与中心差分卡尔曼滤波法(CDKF),构建了一种聚合物锂离子电池的荷电状态(SOC)估计模型.MATLAB仿真验证表明,该模型能有效防止安时计数误差累积,电池SOC估计误差不超过5%.     

环氧树脂基复合材料加筋板结构吸湿行为研究

环氧树脂基复合材料的性能对湿热环境敏感，掌握该材料所组成结构的吸湿行为对其实际应用具有重要意义。通过以碳纤维环氧树脂基复合材料层合板的non-Fickian吸湿模型为基础，建立环氧树脂基复合材料加筋板结构的non-Fickian吸湿模型，在70℃/85% RH湿热条件下开展加筋板结构的吸湿实验，对所建立模型进行验证，并与已有的加筋板吸湿模型进行对比，通过所建立模型给出了加筋板沿厚度方向的吸湿量分布规律。结果表明:所建立加筋板non-Fickian吸湿模型的计算结果与实验结果吻合良好，在整个吸湿阶段相对误差小于5%，模型的预测精度高于传统Fick模型。所建立的加筋板non-Fickian吸湿模型可用于环氧树脂基复合材料加筋板层合结构吸湿量的准确预测。      

磁浮飞行风洞试验技术及应用需求分析

随着高速、超高速轨道交通的快速发展,需要发展新型的风洞设备,实现风洞性能和试验能力的突破.磁浮飞行风洞是利用真空管道列车概念结合动模型试验技术提出的一种新概念风洞设备,可以构建出更加接近真实状态的测试环境.本文从磁浮飞行风洞基本概念、国内外研究现状及发展趋势、试验技术、应用需求等几个方面开展论述.首先论述了国内外传统风洞和动模型设备的现状及发展趋势,指出了发展磁浮飞行风洞的必要性;其次,重点对磁浮飞行风洞需要发展的试验技术进行了分析;最后,对磁浮飞行风洞在超高速轨道交通及其他领域的应用需求进行了展望.     

Scientific objectives and payloads of Tianwen-1, China’s first Mars exploration mission

This paper describes the scientific objectives and payloads of Tianwen-1, China’s first exploration mission to Mars. An orbiter, carrying a lander and a rover, lifted-off in July 2020 for a journey to Mars where it should arrive in February 2021. A suite of 13 scientific payloads, for in-situ and remote sensing, autonomously commanded by integrated payload controllers and mounted on the orbiter and the rover will study the magnetosphere and ionosphere of Mars and the relation with the solar wind, the atmosphere, surface and subsurface of the planet, looking at the topography, composition and structure and in particular for subsurface ice. The mission will also investigate Mars climate history. It is expected that Tianwen-1 will contribute significantly to advance our scientific knowledge of Mars.     

Countermeasure Against Regenerative and Forced Chatter of Flexible Workpieces in Milling Processs Using Bi-directional Excitation

A novel extended methodology for chatter suppression in milling process by applying external forced vibrations to the workpiece in two orthogonal directions which are the feed and cross-feed directions.Both the regenerative and forced chatter suppression during the milling process of flexible workpieces are investigated.Here,the workpiece is subject to a sinusoidal periodic force in the feed direction to disrupt the regenerative effect.Additionally,to minimize the forced chatter,the workpiece is subject to the periodic excitation force in cross-feed direction.This force is proportional to the magnitude of the estimated cutting force in cross-feed direction and has a phase opposite to the cutting force to minimize the vibration amplitudes.The effectiveness of the proposed method is evaluated numerically and experimentally,for the spindle speed located in both the local minima and local maxima of the stability lobe diagram.The numerical simulations indicate significant suppression effect in terms of vibration amplitudes,resulting in suppression of both the regenerative chatter and the forced chatter.Experiments were conducted by using a workpiece-mounted active stage composed of flexure hinges and driven by piezoelectric actuators.The experimental results agree qualitatively with the numerical simulations.The proposed method indicates a remarkable vibration reduction effect for both regenerative and forced chatters.     

Design of Interplanetary Transfers with Passive Gravity Assists and Deep Space Maneuvers

In the paper, the problem of designing interplanetary trajectories with several swing-bys and deep-space maneuvers is solved using the method of virtual trajectories developed by the authors. The algorithms for the calculation of both heliocentric and planetocentric trajectory arcs are presented, including the case of resonant trajectories. The results of applying the method of virtual trajectories to the problem of designing an interplanetary transfer to Jupiter are given and compared with the baseline trajectories for the Juno, Europa Clipper, and Laplace missions.     

eLoran系统ASF网格应用算法研究

ASF网格是提高增强型罗兰（Enhanced Long Range Navigation，eLoran）系统精度的重要方法。根据所在网格四个顶点的附加二次时延（Added Secondary Factor，ASF）值通过网格应用算法得到待测试点的ASF值，一定程度上比公式计算的ASF值更准确。在计算过程中，用户四个顶点ASF值的测量误差会传递给用户，同时内插算法本身也会引入误差，此时内插算法的选择尤为重要。本文通过仿真、分析比较几种常用的内插算法，得出结论：反距离插值算法引入的误差最大，双线应插值算法引入的误差最小，而且误差呈现一定层次感，网格从内到外误差逐渐减小。     

基于DLatLRR与VGG Net的红外与可见光图像融合

针对红外与可见光图像融合中特征损失严重、显著目标不突出的问题，提出了一种低秩表示分解与深度神经网络相结合的图像融合算法。首先，对源图像进行潜在低秩表示分解（DLatLRR），得到相应的低秩部分、显著部分及稀疏噪声。然后，分别采用16层的VGG Net模型和联合特征加权算法对低秩部分与显著部分进行融合，舍弃二者的稀疏噪声。最后，对融合得到的低秩部分和显著部分进行图像重建，得到最终的融合图像。实验结果表明:与其他算法进行比较，所提算法能够对图像的深层次细节特征进行融合，突出场景中的感兴趣区域，且融合图像的相关差异和、结构相似性、线性相关度等多种客观指标均有所提升，提升最大值分别为0.73、0.15、0.11，噪声产生率的最大缩减值为0.041 2。      

Solution of the Problem of Optimal Spacecraft Launching into Orbit Using Reactive Acceleration and Solar Sail in Kustaanheimo–Stiefel Variables

Cosmic Research - Using the Pontryagin maximum principle and the Kustaanheimo–Stiefel variables, the spatial problem of optimal launching into a given orbit of a spacecraft (SC) controlled by...