X-Ray Emission from Flare Collapsing Trap

An acceleration process in the collapsing magnetic trap, formed in the flare with cusp magnetic field topology, is described. Computations show that high-energy electrons are accumulated in the central part of the collapsing magnetic trap due to an increase of their pitch angles. The effect explains in a natural way the formation of X-ray loop-top sources. Then, using the model with the collapsing trap and considering only the adiabatic heating process, a possible explanation for the motion of the X-ray loop-top source observed at the beginning of some cusp-type flares is presented.     

中国空间大功率微波部件微放电抑制表面处理技术最新进展

材料表面的二次电子发射会触发和维持空间高功率射频器件的共振雪崩放电现象,这种现象又被称为微放电效应。微放电效应是限制空间大功率微波部件应用的关键问题之一。从微放电作用的机理出发,首先介绍了两种微放电类型（单表面与双表面）的基本物理机理;然后总结了当前主流的微放电抑制方法并给出各自应用于空间大功率微波部件时的限制。针对空间大功率微波部件微放电抑制的特殊问题,综述了国内近5年来在表面处理法抑制微放电领域的研究成果并预测了微放电抑制技术的发展趋势。     

1992年10月27日耀斑的多波段观测和分析

利用１９９２年１０月２７日耀斑极为完整的高质量观测资料,通过对可见光、软Ｘ射线和硬Ｘ射线图像和光谱的综合分析,诊断耀斑过程中的热与非热性质,结果表明,在这个事件中,热与非热过程并存且在时空演化上呈现不同的特征     

原子氧对航天器表面材料作用的数值模拟

对氏地球轨道环境对航天器表面材料的影响和航天器表面材料的低地球轨道环境寿命评定方法进行了介绍;并对低地球轨道环境和地面试验环境下,有无保护涂层的业胺所受冲蚀作用进行了成功的数值模拟,获得了具有工程应用价值的数值计算结果。该工作对航天器的设计具有指导意义。     

原子氧环境对聚合物及其复合材料性能的影响

在选择卫星结构材料时,必须要对所选材料在宇宙空间环境中的可靠性进行评定,重要的是了解空间环境对材料性能的影响。文章阐述了空间低地球轨道环境中原子氧对聚合物及其复合材料性能的影响;介绍了模拟评定试验材料性能的方法;分析了作用原理、防护措施及选择聚合物复合材料应考虑的原则。     

乙酸铈晶体的红外光谱与热分析

本文制备了乙酸铈品体,EDTA络合滴定法测定其中铈的含量,利用傅立叶变换红外光谱仪对其进行了红外光谱分析,利用高温综合热分析仪对其进行了热重和差热分析,讨论了乙酸铈晶体在空气气氛中的热分解机理。     

Structure of the Program of Short-term Prediction of Powerful Solar Flares

Input data of the system are two-dimensional images and one-dimensional distributions of total and polarized solar emission at 5.2 cm wavelength obtained with SSRT. Together with photoheliograms, magnetograms, Hα-filtergrams and characteristics of active regions received from other sources, they form the initial database. The first stage includes superimposing the images, identifying microwave sources with active regions, assigning NOAA numbers to the sources, and determining for each active region the heliolatitude, extent, and inclination angle of the group's axis to the equator. These data are used to calculate the boundaries of longitude zones for each active region. A next stage involves determining the brightness temperatures of microwave sources less than the polarization distribution, the degree of polarization, and microwave emission flux, as well as calculating the parameters of microwave sources. Each parameter is assigned its own value of the weight factor, and the sum of values is used to draw the conclusion about the flare occurrence probability in each active region and on the Sun in general.      

Experimental Study on Emission Performance of an LPP/TVC

A key issue in the commercial aircraft engine design is environmental acceptability, and designers are continually challenged to reduce emissions. In this paper, an experimental investigation is performed to evaluate the emission performance of a liquid-fueled trapped vortex combustor (TVC) under lean premixed prevaporized (LPP) mode. When operating as an LPP system, a TVC is fueled both in the cavities and in the main stream. The correlations between the emission performance and the total excess air ratio, the positions (4 positions) of the fuel injectors in the main stream, and the inlet temperature are obtained. Experi- mental results show that both the volume concentrations of unburnt hydrocarbon (UHC) and NOx (NO, NO2 usually grouped together as NOx) increase with the increase of total excess air ratio from 1.5 to 3.0; the emission performance relies heavily on the position of the main stream injector, and the best performance is achieved at Position 4 in the experiments; the increase of the inlet temperature impacts on the emission performance positively; the smallest volume concentrations of UHC and NOx obtained in the experiment are 94×10 6 and 2.3×10 6 respectively. This paper validates the feasibility of low emissions for an LPP/TVC and provides a reference for further optimization of TVCs.     

高空环境下喷嘴参数对航空活塞发动机燃烧与性能的影响

以一台四缸四冲程压燃式航空煤油活塞发动机为研究机型,运用工程系统高级建模和仿真平台软件(AMESim)仿真软件建立了发动机的整机模型,并使用台架实验的采集数据对该仿真模型进行了验证。在高空环境中,仿真分析了飞行器起飞工况、最大巡航工况下发动机喷油器的不同喷孔数、孔径对发动机燃烧过程、性能和NOx排放特性的影响。计算结果表明:稳态工况下,随着喷孔数的增加,最高燃烧压力和温度增加,瞬时放热率增长速度快且峰值上升;同时,缸内预混燃烧得到强化,燃烧始点提前,滞燃期和燃烧持续期缩短,燃烧重心前移,循环热效率增高,但同时会提高NOx的生成量;在飞行器瞬态变海拔的起飞工况下,多喷孔数、小孔径的喷油嘴有利于航空活塞发动机在高空环境下恢复发动机功率,提升飞行器的动力性和续航性能。