熔融石英半球谐振子亚表面缺陷的湿法刻蚀工艺

为了提高半球谐振子的品质因数,提出采用湿法刻蚀的方法去除半球谐振子亚表面的微缺陷。通过研究熔融石英材料的湿法刻蚀机理,在专用半球谐振子湿法刻蚀设备上能够稳定实现半球谐振子亚微米刻蚀精度,半球谐振子经过湿法刻蚀后表面粗糙度优于100nm,半球谐振子Q值能够提高至2000万以上,半球谐振子频差变化小于0.03Hz。     

基于注意力机制和改进YOLOv3的红外弱小目标检测

红外弱小目标检测技术是红外探测系统的核心技术之一。针对远距离复杂场景下红外弱小目标对比度低、信噪比低和纹理特征稀疏分散导致目标检测率低的问题,提出一种融合注意力机制和改进YOLOv3的红外弱小目标检测算法。首先,在YOLOv3的基础上,用更大尺度的检测头替换最小尺度的检测头,在保证推理速度的基础上有效提升了红外图像中小目标的检测概率。然后,在检测头之前设计了Infrared Attention模块,通过通道间的信息交互,抽取出更加关键重要的信息供网络学习。最后,用完全交并比损失（Complete IoU Loss）替代交并比损失（Intersection over Union Loss）来衡量预测框的检测能力,通过梯度回传实现更好的模型训练。实验结果表明,本文提出的YOLOv3-DCA 能完成多种场景下红外弱小目标的检测任务,且检测准确率、召回率、F1和平均准确率分别达到91.84%、88.85%、93%和88.82%,平均准确率比YOLOv3基线提升约7%,与主流的SSD、CenterNet和YOLOv4模型对比平均准确率也取得了目前最优。     

基于变分迭代的航天器相对姿轨耦合动力学解算方法

针对航天器相对姿轨耦合一体化运动,在定义坐标系下利用对偶四元数和旋量表示航天器的一般运动,推导出航天器六自由度运动学和动力学模型,并分别采用Runge-Kutta四阶算法和变分迭代法的配点形式求解该非线性模型。变分迭代法的配点形式是变分迭代法与配点法的复合,本文先给出变分迭代法的迭代方程,再把迭代方程应用到局部时间区间上探讨了局部变分迭代法,然后把变分迭代法与配点法结合得到数值迭代方程。利用对偶四元数所建立的模型相对于其他模型较为简洁,便于分析姿轨耦合特性。仿真结果表明,相比Runge-Kutta四阶算法,变分迭代法的解算精度更高。     

基于改进SSD的风机叶片表面缺陷检测方法

针对无人机对风机叶片表面缺陷检测中出现的多尺度目标问题,本文提出一种基于改进SSD的风机叶片缺陷检测方法。以具有多尺度结构框架的目标检测模型SSD为基础,引入残差网络ResNet50作为其特征提取网络,用以获取更深层次的细节特征信息,从而提升缺陷检测模型的整体效果。在建立的风机叶片表面缺陷图像数据集下进行模型验证,结果表明,该方法的平均精确度mAP@.5为84.29%,与YOLOv3和RetainNet相比,对各类型缺陷的平均精确度分别提高了2.92%和8.69%,同时较传统SSD算法平均精确度提升了2.21%。     

Non-cultural methods of human microflora evaluation for the benefit of crew medical control in confined habitat

Current control of human microflora is a great problem not only for the space medicine but also for practical health care. Due to many reasons its realization by classical bacteriological method is difficult in practical application or cannot be done.To evaluate non-cultural methods of microbial control of crews in a confined habitat we evaluated two different methods.The first method is based on digital treatment of microbial visual images, appearing after gram staining of microbial material from natural sample. This way the rate between gram-positive and gram-negative microbe could be gained as well as differentiation of rods and cocci could be attained, which is necessary for primary evaluation of human microbial cenosis in remote confined habitats.The other non-culture method of human microflora evaluation is gas chromatomass spectrometry (gcms) analysis of swabs gathered from different body sites. Gc-ms testing of swabs allows one to validate quantitative and special microflora based on specific lipid markers analysis.     

基于控制系统工作原理的视线角速度获取方法

针对红外成像导引头弹目视线角速度获取精度较差,无法满足导弹制导指标要求的问题,根据红外导引头角跟踪原理,比较研究了直接微分法、基于马尔科夫模型的方法和基于控制系统工作原理的方法3种弹目视线角速度提取方案。利用试验数据进行了仿真分析。仿真结果表明:直接微分法和基于马尔科夫模型的方法均不适用于红外成像导引头弹目视线角速度提取。将控制系统设计为二阶无静差系统,并以此建立了基于控制系统工作原理的弹目视线角速度提取模型。仿真分析表明:该方法适用于红外导引头弹目视线角速度提取。     

基于灰度预测的无刷直流电机控制

针对传统PID控制器抗干扰能力差，参数调节繁琐等问题，提出了灰度预测控制器。对灰度预测算法进行了详细的理论分析和数学建模，利用最速梯度法对控制器参数进行调整，设计了参数自适应调整的控制器；对飞轮使用的无刷直流电机进行了较为准确的模型建立，并在此基础上设计了基于灰度预测控制器的电机控制仿真模型。通过仿真分析了两种控制器在正常加速和受到干扰两种情况下的不同表现，验证了灰度预测控制器在调节效果和稳定性等方面的优越性。     

基于波前编码的红外光学系统低成本无热化设计

波前编码技术通过特殊面型的相位板对光束进行编码，拓展系统焦深，使之对热离焦不敏感，再结合数字图像处理，解码获得清晰图像，实现无热化设计。将波前编码技术应用在某一长波红外光学系统无热化设计中，对比了原光学系统和波前编码系统的点扩散函数、光学传递函数、模拟成像质量及公差分析。结果表明，波前编码技术可以为红外成像系统提供具有价格竞争力的无热化方案，可使红外光学系统在-40℃至60℃范围内获得良好且稳定的工作性能。     

高精度星敏感器热设计研究及仿真验证

为实现某高精度星敏感器在空间复杂热环境下的可靠应用,对该星敏感器的热设计进行了分析研究,并选取典型的高温工况和低温工况进行讨论。基于热网络模型对高温工况和低温工况计算及仿真分析,提出了星敏感器与卫星舱体在导热和隔热2种安装情况下的热控措施。分析结果表明:当星敏感器导热安装时,将安装面温度控制在-15～0℃,在其外表面包覆多层隔热组件,可使整机温度适宜;当星敏感器隔热安装时,在其盖板外表面喷涂热控白漆,将遮光罩与盒体隔热安装,设置用于温度补偿的电加热片,将安装面温度控制在-60～-30℃。     

A new chapter in doctoral candidate training: The Helmholtz Space Life Sciences Research School (SpaceLife)

In the field of space life sciences, the demand of an interdisciplinary and specific training of young researchers is high due to the complex interaction of medical, biological, physical, technical and other questions. The Helmholtz Space Life Sciences Research School (SpaceLife) offers an excellent interdisciplinary training for doctoral students from different fields (biology, biochemistry, biotechnology, physics, psychology, nutrition or sports sciences and related fields) and any country. SpaceLife is coordinated by the Institute of Aerospace Medicine at the German Aerospace Center (DLR) in Cologne. The German Universities in Kiel, Bonn, Aachen, Regensburg, Magdeburg and Berlin, and the German Sports University (DSHS) in Cologne are members of SpaceLife. The Universities of Erlangen-Nürnberg, Frankfurt, Hohenheim, and the Beihang University in Beijing are associated partners.In each generation, up to 25 students can participate in the three-year program. Students learn to develop integrated concepts to solve health issues in human spaceflight and in related disease patterns on Earth, and to further explore the requirements for life in extreme environments, enabling a better understanding of the ecosystem Earth and the search for life on other planets in unmanned and manned missions.The doctoral candidates are coached by two specialist supervisors from DLR and the partner university, and a mentor. All students attend lectures in different subfields of space life sciences to attain an overview of the field: radiation and gravitational biology, astrobiology and space physiology, including psychological aspects of short and long term space missions. Seminars, advanced lectures, laboratory courses and stays at labs at the partner institutions or abroad are offered as elective course and will provide in-depth knowledge of the chosen subfield or allow to appropriate innovative methods. In Journal Clubs of the participating working groups, doctoral students learn critical reading of scientific literature, first steps in peer review, scientific writing during preparation of their own publication, and writing of the thesis. The training of soft skills is offered as block course in cooperation with other Helmholtz Research Schools. The whole program encompasses 303 h and is organized in semester terms. The first doctoral candidates started the program in spring 2009.