钛合金表面抗激光涂层损伤特性及热效应影响研究

实验研究了钛合金和高反射型陶瓷涂层材料抗连续型激光烧蚀的损伤及温度分布特性，并从热效应影响角度对比分析了二者在抗激光损伤效果方面的差异性。研究结果表明：相比于钛合金，高反射型陶瓷涂层材料能有效增强钛合金基底抗激光损伤的能力；在同等激光功率密度辐照下，陶瓷涂层材料能有效提升钛合金基底耐受激光辐照的时间长度。实验结果表明该陶瓷涂层材料的激光损伤阈值比钛合金高约5.8倍。实验发现陶瓷涂层温升速率高于钛合金，但由于陶瓷材料具有较高的反射特性，以及良好的热吸收和热传导特性，因此能使由激光辐照产生的热量在其表面较快地扩散，而降低向基底方向传导的程度，最终提升陶瓷涂层的抗激光损伤阈值。     

Orbit-attitude-vibration coupled dynamics of tethered solar power satellite

A new orbit-attitude-vibration coupled dynamic model of the tethered solar power satellite (Tethered SPS) is established based on absolute nodal coordinate formulation. The Hamilton’s equation of the system is derived by introducing generalized momentum through Legendre transformation. The correctness of the proposed model is verified by an example. The dynamic characteristics of the Tethered SPS are studied using the symplectic Runge-Kutta method. Simulation results show that the orbital radius and the total energy of the system are well preserved. The attitude of the system is unstable when the mass of the bus system is small. However, the attitude stability is dependent on some other parameters of the system, which requires further studies. It is also found that the average tether force/deformation can be roughly estimated by simplifying the solar panel as a particle. The proposed model can be used to study the orbit-attitude-vibration coupled dynamics and control problems.     

Effect of matching between the magnetic field and channel length on the performance of low sputtering Hall thrusters

Discharge characteristics of a non-wall-loss Hall thruster were studied under different channel lengths using a design based on pushing a magnetic field through a double permanent magnet ring. The effect of different magnetic field intensities and channel lengths on ionization, efficiency, and plume divergence angle were studied. The experimental results show that propellant utilization is improved for optimal matching between the magnetic field and channel length. While matching the magnetic field and channel length, the ionization position of the neutral gas changes. The ion flow is effectively controlled, allowing the thrust force, specific impulse, and efficiency to be improved. Our study shows that the channel length is an important design parameter to consider for improving the performance of non-wall-loss Hall thrusters.     

电铸镍Wolter I型光学系统制造技术发展综述

摘要： 为满足未来脉冲星导航和空间天文观测任务对X射线望远镜的载荷需求，Wolter I光学系统的研制正逐渐成为新的研究热点，电铸镍方案是当前国内外X射线光学系统镜筒制造的主要技术方案.文章对电铸镍X射线光学系统制造工艺、国内外研制现状、未来应用需求进行了介绍和整理，梳理了电铸镍X射线光学系统研制遇到的关键技术和难点，提出了后续研究发展建议，以促进中国在 X射线脉冲星自主导航、空间探测领域的快速发展.     

流动阻力及能量损失对注射成型制件的影响

本文分析了在塑料熔体充满型腔的过程中，流动阻力及能量损失产生的形式和物理原因，进而讨论了对塑料制件成型及凝固过程中的影响。并提出降低影响的措施。     

进气道喘振诱发因素及其可靠性分析

针对飞机进气道的典型故障-喘振的诱发因素进行全方位的分析论证，并为从事航空工程的人员提供一种对动力装置整体性能进行可靠性评估方案，篇末对世界上比较先进的进气道气动设计思想及其喘振机理进行分析，可以为飞机设计师在设计飞机过程中具体分析问题提供一定的参考。     

专科英语、本科英语及成人专科英语的定位和相互关系

专科英语在理论上被界定为专门用途英语(ESP)分支下,介于学术英语(EAP)与职业英语(EOP)之间的业务用途英语(EPP)。而本科(大学)英语在理论体系上属于普通英语(GE)。本文从ESP理论的角度探讨了专科英语,本科英语及成人专科英语的定位和相互关系。     

平面形状误差分离方法的比较分析

就十种典型的精密平面形状误差测量－分离方法的权函数及其零点，作了分析比较。按形状误差谐波抑制最小准则，论证了五点式正交逐次三点法、九点式正交逐次三点法、复合三点法、不对称二维混合法和不对称四点法优于其他方法，不对称四点法则较为理想。     

rom 15 sel

with primary goat embryonic fibroblast showed no difference from traditional feederlayer-based culture method used in mouse and human. The putative primary EG colonies were multilayer clumps ofcompact cel     

用于卫星推力室的新型催化剂

卫星上安装有用于轨道和姿态控制的小推力推力室。推力由三氧化二铝基的铱催化剂分解无水肼而产生。铱催化剂的主要缺点是成本高和生产技术复杂。目前的工作是把钼(M)、钨(W)的碳化物与氮化物的合成过程与成型联系起来,形成有大、中孔隙的新型催化剂,来代替昂贵的传统催化剂30%铱——三氧化二铝(即shell-405_(TM))。在这种新的工艺中,首先是制备胶状的钨酸和钼酸;然后把这些材料与有机聚合物混合,使之生成胶体溶液;再挤压成型。其次把生成的这些中间过渡产品送去加热处理,焚烧掉有机聚合物得到所期望的有大、中孔隙的氧化物。最后一步是按照Boudart和Volpi方法利用挤出物制备氮化物和碳化物。本文给出了用2N推力室试验新催化剂的主要试验结果,同时与Shell 405~(TM)的试验结果进行了比较。试验表明新催化剂有如下特点:比表面积大;能承受高达1100K的烧结温度;热试时室压和推力高度稳定,催化剂机械强度高。新催化剂的主要优点是生产工艺更简单而且成本更低。