离子推进器C/C复合材料栅极研究

栅极是离子推进器的关键部件之一,直接影响推进器的可靠性和寿命。由于C/C复合材料栅极具有比较小的热膨胀系数和较强的耐溅射性,可以提高离子推进器的可靠性并延长其寿命。文章通过调研综述C/C复合材料栅极的研究和应用发展状况,针对目前我国离子推进器的研究发展水平,提出开展C/C复合材料栅极研究工作的初步思路。     

质子辐照对防静电热控涂层导电性能影响

文章研究了质子辐照环境对两种防静电热控涂层（ITO/F46/Ag、ITO/OSR/Ag）导电性能的影响,质子总注量选取1×1015 p/cm2,并在不同质子注量下对试样表面电阻率进行了原位测量。试验发现,质子辐照下两种防静电热控涂层的表面电阻率均呈指数衰减趋势,且回至大气中出现明显的“恢复效应”。对涂层导电性能退化的微观机制进行了分析,并建立了相应导电性能演化规律的简化数学模型,可为新型涂层的研制提供理论依据。     

Relationship of the diffuse aurora and SAR arc dynamics to substorms and storms

Investigation results of a diffuse aurora (DA) and stable auroral red (SAR) arc dynamics based on spectrophotometric observations at the Yakutsk meridian (199°E geomagnetic longitude) are presented. The relationship of an equatorward extension of DA in the 557.7 nm emission to a substorm growth phase during the magnetospheric convection intensification after the turn of IMF B_Z to the south is shown. The formation of SAR arc during the substorm expansion phase is investigated. The association of SAR arc dynamics with the development of asymmetric ring current (substorm injection) during the main phase of a storm is analyzed. It is shown how the pulsating precipitations of energetic ring current particles develop in the outer plasmasphere based on photometric observations.     

飞机电网直流电压畸变信号测试方法

随着飞机上非线性负载的增加，它们对电网的影响越来越引起人们的重视。本文采用模拟滤波和数字信号处理技术，完成了对飞机电气系统直流电压畸变的测试，给出了对某型飞机电网的实际测试结果。     

机电产品安全风险评价模型研究

目前，我国的机电产品在其全寿命周期中基本上不做安全风险评价，一个重要的原因是缺乏有效的风险评价模型。为此，本文提出了一种适合于我国机电产品在设计阶段进行风险评价的通用模型。     

GH4169铸锭中夹杂物的类型及分布规律

高温合金中夹杂物是影响合金冶金质量和使用性能的主要因素。采用三联冶炼工艺对GH4169合金进行冶炼，并利用配有能谱仪的扫描电镜系统研究了VAR铸锭边缘及顶端区域夹杂物类型与分布的变化情况，为夹杂物的进一步控制提供参考。结果表明，在横向方向上，随试样所在位置远离铸锭边缘，夹杂物的平均尺寸由3.15 μm递减至2.58 μm，其数量密度由2 291 N/mm²（N代表夹杂物个数）降低至1 429 N/mm²；在纵向方向上，随试样所在位置远离铸锭顶端，夹杂物的平均尺寸由3.47 μm递减至2.84 μm，其数量密度由1 453 N/mm²降低至904 N/mm²，而合金中均包含5种类型的夹杂物，其类型与试样所在位置无关。最终，本实验初步判定φ508 mm的GH4169铸锭较为合适的车削量与切头量分别为30~40 mm和110~120 mm。     

A global solution for robust parameter design of aeronautical electrical apparatus based on interactions analysis and polynomial fitting

Robust Parameter Design (RPD) has been widely applied for improving quality and reliability of products. One of the key drawbacks of applying RPD using Taguchi method is that the stable factors may not be independent of the adjustment factors, resulting in unsatisfactory design. Moreover, the Taguchi method cannot guarantee global optimality since the levels set in the experiment are usually discrete to ensure orthogonal design. In this paper, robust solutions of the stable factors are obtained via a nonlinear model based on polynomial fitting; while the adjustment factors are obtained via interactions analysis so that they are independent of the stable factors. In particular, the values of the adjustment factors are determined by output offset compensation so as to achieve robustness of the design scheme. An example on the design of an aeronautical electrical apparatus is presented to illustrate the procedure. The results show that the proposed method can take full advantage of the nonlinearity in the response and achieve the desired outcome.     

连续短线段空间圆弧转接与插补

针对连续短线段高速加工控制需求,研究了利用空间圆弧转接实现高速插补的方法。建立了圆弧转接数学模型,研究了转接的几何约束和运动约束、转接参数计算、空间圆弧插补等相关理论与算法,并详细分析了算法的使用范围、效率制约因素和计算量等工程实现相关问题。仿真和加工实验表明:该转接算法能显著提高加工效率,减小振动,改善工件表面质量。作为空间圆弧转接算法基础的空间圆弧插补算法对空间任意平面内圆弧插补具有实用价值。本文所有算法已经在自主研发的数控平台上进行了验证,应用效果良好。     

航空电气系统绝缘电阻自动测试系统

针对飞机电气系统绝缘测试部位和设备数量繁多、手动测试效率低、容易造成事故隐患等问题,介绍了一种航空电气系统绝缘电阻的自动化测试方法,设计并实现了通用航空电气系统绝缘电阻自动测试系统、该系统运用工控机自动控制与测试技术,自动完成测试,并实现数据处理、信息存贮等功能。应用表明该系统安全可靠、自动化程度高、测试速度快、可扩展性强。     

TA15钛合金薄板等离子弧对接焊缝疲劳特性研究

为了探索钛合金等离子弧焊接头的疲劳性能,本文依据TA15标准试件和轧制板材试件疲劳试验数据处理结果,采用当量应力集中系数法,在TA15薄板等离子弧焊和对接焊缝磨削组合工艺试件的疲劳试验基础上,确定了中值当量应力集中系数和安全当量应力集中系数,最后建立了该TA15薄板的S-N曲线,给出了应用结论。