空管班组失误分析

实施空中交通管制,是管制员利用无线电语音通讯传达意志,实现航空器在空中快速、有序、安全流动的一项具有责任大、风险高的工作。在复杂的空管系统中,随着硬件设备可靠性不断提高,管制员的失误已经成为诱发事故和不安全事件的因素之一。因此,探讨空管系统的可靠性,必须充分考虑人(管制员)的可靠性因素,特别是班组中人与人之间相互作用对系统可靠性的影响。1996年和1997年,我国空管连续发生了多起因单岗管制席位造成的不安全事件,引起了民航总局空管局的高度重视,于1997年9月制定了双岗制行业要求,并于次年8月全面建立、推行了双岗制。这一…     

Thermal protection mechanism of heat pipe in leading edge under hypersonic conditions

Sharp local structure, like the leading edge of hypersonic aircraft, confronts a severe aerodynamic heating environment at a Mach number greater than 5. To eliminate the danger of a material failure, a semi-active thermal protection system is proposed by integrating a metallic heat pipe into the structure of the leading edge. An analytical heat-balance model is established from traditional aerodynamic theories, and then thermal and mechanical characteristics of the structure are studied at Mach number 6–8 for three refractory alloys, Inconel 625, C-103, and T-111. The feasibility of this simple analytical method as an initial design tool for hypersonic aircraft is assessed through numerical simulations using a finite element method. The results indicate that both the isothermal and the maximum temperatures fall but the von Mises stress increases with a longer design length of the leading edge. These two temperatures and the stress rise remarkably at a higher Mach number. Under all investigated hypersonic conditions, with a 3 mm leading edge radius and a0.15 m design length, the maximum stress exceeds the yield strength of Inconel 625 at Mach numbers greater than 6, which means a material failure. Moreover, both C-103 and T-111 meet all requirements at Mach number 6–8.     

Thermal shock damage behavior of CVD ZnS by oxygen propane flame：A numerical and experimental study

Chemical vapor deposition zinc sulfide （CVD ZnS） is widely used as an infrared window material to transmit infrared signals, keep the aerodynamic shape and protect its imaging system, which often suffers high temperature and complicated thermal stresses. The purpose of this paper is to investigate the thermal shock damage of CVD ZnS through a finite element method and oxygen propane flame experiments. The finite element model is developed to simulate the temperature and thermal stress fields by an oxygen propane flame. Then, the thermal shock experiments are performed to investigate the thermal shock damage behavior. The results show that the temperature rising rate of the shock surface is fast during the initial heating stage resulting in high thermal stress. After the thermal shock experiment, the scanning electron microscope （SEM） photographs shows that the shock surface of the specimen becomes rough and the microcracks occur in the thermal shock zone. Good agreements are achieved between the numerical solutions and the experimental results.     

碳化硼对碳／碳复合材料的催化石墨化作用

本文研究了用Ｂ４Ｃ作催化剂，以降低Ｃ／Ｃ复合材料的石墨化温度，并比较分析了添加Ｂ４Ｃ后，对Ｃ／Ｃ复合材料力学、热物理性能的影响。结果表明，添加Ｂ４Ｃ后，在比通常石墨化温度低４００℃的情况下，石墨化度反而增加了１４％，达到了８５％。Ｃ／Ｃ复合材料的抗热震性能也有提高。同时应用Ｘ射线衍射（ＸＲＤ）、Ｘ射线光电子能谱（ＸＰＳ）等分析手段，分析了Ｂ４Ｃ对Ｃ／Ｃ复合材料的催化石墨化机理。     

耐久性分析技术的发展与改进

阐述了美国空军耐久性设计手册（第二版）所做的发展，并指出其中存在的两个问题，即确定裂纹扩展率参数Ｑ时未考虑裂纹萌生时间的重要作用和没有说明使用期裂纹扩展率标准差σｚ的确定方法。通过研究，改进了裂纹扩展率参数Ｑ的确定方法，补充了确定裂纹扩展率标准差σｚ的途径，并通过了实验验证。     

弹性飞行器纵向稳定性问题

 本文研究考虑气动弹性时飞行器的纵向稳定性问题。首先由弹性飞行器的纵向扰动运动方程出发,导出了便于计算采用的弹性飞行器纵向扰动方程的标准矩阵形式,作出作为控制对象的弹性飞行器在考虑一阶、二阶及三阶振型时的传递函数;其次分析气动弹性对整个飞行器系统的稳定性的影响,并提出对飞行器自动驾驶仪敏感元件的可能合适位置选择的要求。最后还建立了计算气动弹性对飞行器气动导数值影响的理论式。     

剪切电子散斑干涉在蜂窝夹层粘接质量检测中的应用

介绍了激光电子剪切散斑干涉成像系统的原理;用该系统检测了蜂窝结构件的缺陷,缺陷散斑图像清晰可辨。试验表明,该系统可用于复合材料结构和蜂窝夹层结构的无损检测。     

加热炉助燃氧量控制系统

本文介绍了一种以微处理器为基础的助燃氧量控制系统，阐述了用氧化锆为传感元件测量烟气中氧量的原理和应用结果。     

一种快速制备C/C材料方法的探索研究

介绍了一种新的Ｃ／Ｃ材料制备方法－－快速化学液气相渗透致密法。利用该技术,采用碳毡作预制体,以两种液态低分子有机物作碳源前驱体沉积时间在３ｈ内,沉积温度在９００℃￣１１００℃范围内可获得密度达１．７４ｇ／ｃｍ＾３的Ｃ／Ｃ材料。碳纤维表面最大沉积速率可达６４μｍ／ｈ,比传统的等温ＣＶＩ沉积速率（０．１μｍ／ｈ￣０．２５μｍ／ｈ）提高了２００倍以上,并初步分析了该技术快速致密多孔预制体的机理。     

耐高温聚酰亚胺结构胶黏剂的研究

合成了以苯乙炔基封端的系列聚酰亚胺胶黏剂,研究了分子结构、分子量、固化工艺等因素对其耐热和粘接性能的影响规律.结果表明:合成的聚酰亚胺胶黏剂具有优异的耐热和高温粘接性能,对不锈钢试片粘接的剪切强度在316℃下≥10 MPa,在400℃下为3 MPa.