千兆赫横电磁室（GTEM）的原理和计算方法

GTEM是几年前才发明的EMC/EMI测量装备,具有很大的重要性。文章重点论述以下几个问题:(1)传统的横电磁传输室(TTC)的缺点;(2)GTEM的原理及可能达到的技术指标;(3)特性阻抗的无穷级数公式;(4)对特性阻抗进行编程计算的方法,以及计算实例。最后,讨论了准静态分析所存在的问题,从而明确了进一步研究的方向。     

Numerical investigation on the shock wave transition in a three-dimensional scramjet isolator

The scramjet isolator, which is used to prevent the hypersonic inlet from disturbances that arise from the pressure rise in the scramjet combustor due to the intense turbulent combustion, is one of the most critical components in hypersonic airbreathing propulsion systems. Any engineering error that is possible in the design and manufacturing procedure of the experimental model, and the intense heat release in the scramjet combustor, may cause the performance of the isolator to decrease, leading to its lack of capability in supporting the back pressure. The coupled implicit Reynolds Averaged Navier–Stokes (RANS) equations and the two-equation standard k?ε turbulent model have been employed to numerically simulate the flow fields in a three-dimensional scramjet isolator. The effects of the divergent angle and the back pressure on the shock wave transition and the location of the leading edge of the shock wave train have been estimated and discussed. The obtained results show that the present numerical results are in very good agreement with the available experimental shadow-pictures, and the numerical method is more suitable for capturing the shock wave train and predicting the location of the leading edge of the shock wave train in the scramjet isolator than the present two-dimensional numerical methods. This is due to the small width-to-height ratio of the isolator and the intense three-dimensional flow structures. On increasing the divergent angle of the scramjet isolator, the static pressure along the central symmetrical line of the isolator decreases sharply. This is due to the strong expansion wave generated at the entrance of the isolator, and when the divergent angle of the isolator is sufficiently large, namely 1.5°, a zone of negative pressure is formed just ahead of the leading edge of the shock wave train. At the same time, the shock wave train varies from being oblique to being normal, and then back to oblique. With an increase in the prescribed back pressure at the exit of the scramjet isolator, the leading edge of the shock wave train moves forward towards the entrance of the isolator, and when the back pressure is sufficiently large, unstart conditions in the hypersonic inlet can take place if the shock train reaches the inlet.     

强5E型飞机颤振特性分析

根据强5飞机以往型号的颤振计算结果，对强5E型飞机的两种外挂状态（全机＋2×LS－500J激光弹。全机＋2×LS－500J激光弹＋2×4001副油箱）作了颤振特性分析。     

大迎角体涡,翼涡干扰的Euler方程数值模拟

本文用Ｅｕｌｅｒ方程的简化区算法计算翼－身组合体绕流。当大迎角时，计算能自动捕捉到大后掠前缘的分离涡，机射的分离涡由强加Ｋｕｔｔａ条件生成，形成体涡与翼涡的相互干拢。本文对加长前机身的ＡＧＡＲＤ－Ｂ翼－射组合体模型，给出机射有分离和无分离时，横流截面的速度矢量分布、法向力和压力中心，分析体涡的影响。     

燃烧室内壁数字化加工技术研究

针对火箭发动机燃烧室内壁型槽复杂、加工效率低和质量不稳定的难题,利用加工中心数字仿真技术,对加工中心整体装配建模,进行数字化加工工艺过程整体仿真,研究五轴棒铣刀加工技术,革新了原有的螺旋槽片铣刀加工工艺方案,提出薄壁螺旋槽燃烧室内壁零件加工中心高效加工工艺技术方案,加工质量显著提高,加工效率提高近3倍,工艺改进后的零件经过装配热试车考核满足要求.     

定标系统光源控制电路设计

文章介绍了某型号定标系统光源控制电路的设计。     

The accuracy of ionogram-derived N(h) profiles

At the Millstone Hill station the Incoherent Scatter Radar (ISR) and a Digisonde 256 are simultaneously operating. Some characteristic true heights determined by both instruments are compared with each other, possible reasons for observed difference are indicated.     

横电磁传输室理论与技术的若干问题

横电磁传输室(TEM cell)由于其全封闭式结构,不会污染环境或影响操作人员的健康,因而比敞开式带状线测试室优越。从内部场分布看,扁结构(矩形截横面)优于方结构(方形横截面)。电磁场数值解法(先求导积分方程然后化为矩阵代数方程)不仅对传统结构有效,而且可用来计算一些可想象的新结构。文中给出了作者针对小型室和中型室进行大量测试得到的实验结果。并据此导出了最高可用频率(UUFL)的经验公式。最后,提出了在今后研究工作中应优先解决的问题。     

中、小城市城中村现象形成原因分析

本文旨在对我国城市化进程中出现的“城中村”现象形成的原因进行分析，并分析由此带来的危害，促进我国城镇发展战略的健康发展。     

同轴线的时域并矢格林函数及特性分析

本文利用Ohm-Rayleigh法导出了同轴线的时域并矢格林函数,并修正了[1]的错误。同时也指出了[2]在修正[1]时的不足。文中还讨论了理想探针激励下同轴线的瞬变特性,分析了高次模的时域波形性质。这对进一步分析同轴线在时域中工作的特点有一定的指导意义。