用线性曲线拟合判断固态功率放大器饱和点

在自动化测量系统中,软件需要根据测量数据自动寻找并判断功率放大器的饱和点。在受噪声影响较大的在轨测试中,这是个难点。本文根据固态功率放大器AM/AM特性曲线的特点,提出一种使用多项式线性曲线拟合测量数据建立增益曲线预测关系式,并通过增益趋势线准确判断饱和点的方法。经过真星在轨测试验证,该方法与实际特性吻合很好。     

APU飞机级控制系统设计研究

为充分发挥APU（辅助动力装置）在民用飞机上的作用,设计一个好的APU控制系统显得尤为重要。对APU飞机级控制系统的设计进行了相关研究,论述了APU控制板、APU控制器供电、燃油控制、应急停车、APU引气、起动／发电、风门控制和指示告警等控制子系统在设计时所要考虑的因素,并给出了相应的设计样例,然后从功能实现和电气原理的角度进行了详细地分析,可为APU飞机级控制系统的方案设计提供参考。     

民用飞机配电网络过流保护分析方法研究

飞机配电网络过流保护分析是验证飞机电网设计合理性、可靠性和安全性的重要内容之一.因此,主要对飞机配电网络过流保护分析方法进行了研究,并提出了一种特性曲线法.该特性曲线法基于导线载流特性曲线和电网保护装置过流保护动作特性曲线,分析方法简单、实用,可用于支持合格审定阶段飞机配电网络设计验证.     

Energy-efficiency maximization for fixed-wing UAV-enabled relay network with circular trajectory

With the development of Unmanned Aerial Vehicles (UAVs), the applications of UAVs have been extensively explored. In the field of wireless communications, the relay nodes are often used to extend network coverage. However, traditional fixed ground relays cannot be flexibly deployed due to their low heights and fixed locations. Hence, deploying UAV as relay node is a promising solution and has become a research hotspot. In this paper, we consider an UAV-enabled relaying network in which a fixed-wing UAV is deployed between the Base Station (BS) and Ground Users (GUs). We study the energy-efficiency gap between the link “BS-UAV-GUs” and the link “BS-GUs”, and jointly optimize UAV relay transmission power and flight radius to achieve the highest energy-efficiency. Firstly, the UAV/BS-GUs channels models and the UAV energy consumption model are built. Secondly, the optimization objective function is formulated to maximize the energy-efficiency gap. Then, the solution of the optimization problem is divided into a two-step iteration process, in which the UAV relay transmission power and flight radius are adjusted to maximize the energy-efficiency gap. Finally, the experimental results under different simulation scenarios (such as cities, forests, deserts, oceans, etc.) are shown to illustrate the effectiveness of the proposed algorithm. The results show that the proposed algorithm can always find the optimal UAV relay transmission power and flight radius settings, and achieve the largest energy-efficiency gap. The convergency speed of the proposed algorithm is fast, and can obtain the optimal solution within only a few iterations.     

基于LNOI的集成化光纤陀螺用功率分束器研究CSCD

设计了一种基于绝缘体上铌酸锂(LNOI)的片上多模干涉(MMI)波导功率分束器,在5μm×45μm的小尺上实现了1×2的片上分束功能,且满足集成化光纤陀螺的光路应用要求。通过理论公式和有限时域差分法对器件进行了关键参数计算和光场仿真,MMI干涉区长度为20μm,优化输出分支间距并增加宽度为1.7μm的锥型波导后,在100nm的光谱宽度中,功率分束器的归一化输出光强较为平坦,最低规一化输出光强为0.965,两输出分支的光功率不均匀度仅为10量级。     

民用飞机短舱防冰系统冻雾天试验方法研究

民航规章25部1093(b)(2)条款要求短舱防冰系统在冻雾天环境中性能满足要求,通过构建开放式结冰条件模拟装置,对民用飞机短舱防冰系统在特定的地面冻雾条件下的性能进行了验证,试验对象是装机后的短舱防冰系统,在真实的飞机发动机运转条件下进行适航验证试验,表明短舱防冰系统对民航25部适航规章1093(b)(2)条款的符合性,详细给出了民用飞机短舱防冰系统地面冻雾天试验的方法。该试验方法成功在某型飞机上实施,试验方案科学合理,试验方法可以为其他型号飞机地面冻雾天试验提供参考。     

汽车动态测试-DVT

介绍了DVT测试这一先进的汽车动态测试和诊断手段的发展，并结合生产实际介绍了DVT测试的全过程，同时列举了一些典型的故障分析诊断实例，阐释了DVT测试的优点，它能够方便、快速地诊断出汽车的故障，保证汽车的装配质量，提高汽车出厂安全系数。     

Effects of space weather on high-latitude ground systems

Geomagnetically induced currents (GIC) in technological systems, such as power grids, pipelines, cables and railways, are a ground manifestation of space weather. The first GIC observations were already made in early telegraph equipment more than 150 years ago. In power networks, GIC may saturate transformers with possible harmful consequences extending even to a collapse of the whole system or to permanent damage of transformers. In pipelines, GIC and the associated pipe-to-soil voltages may enhance corrosion or disturb surveys associated with corrosion control. GIC are driven by the geoelectric field induced by a geomagnetic variation at the Earth’s surface. The electric and magnetic fields are primarily produced by ionospheric currents and secondarily affected by the ground conductivity. Of great importance is the auroral electrojet with other rapidly varying currents indicating that GIC are a particular high-latitude problem. In this paper, we summarize the GIC research done in Finland during about 25 years, and discuss the calculation of GIC in a given network. Special attention is paid to modelling a power system. It is shown that, when considering GIC at a site, it is usually sufficient to take account for a smaller grid in the vicinity of the particular site. Modelling GIC also provides a basis for developing forecasting and warning methods of GIC.     

返回式卫星的供配电系统

供配电系统是卫星的一个重要分系统。卫星飞行任务的圓满完成,依赖于供配电系统的正确和可靠地工作。供配电系统包括电源的产生、电源的分配和控制、电源的贮存和电缆网等。文章首先讨论返回式卫星的任务和特点,然后给出供配电系统的设计方法。特别对配电准则、配电方案(集中制、分散制和混合制)和配电器的设计作了详细的描述。     

航空发动机成附件振动环境试验剖面确定方法研究

针对航空发动机成附件振动环境试验需求,论述了发动机成附件的可靠性试验、功能性试验、耐久性试验以及强化试验的功用与实施流程,明确了各振动环境试验剖面制订中的基本要求.阐述了四类振动环境试验剖面的详细确定步骤、分析方法以及应遵循的基本原则,发展和完善了基于环境测试数据(功率谱密度样本)的振动环境试验剖面确定方法.通过工程实例分析,使读者对试验剖面确定流程形成直观认识,对位于风扇机匣位置的成附件而言,试验剖面的各频段分别用以反映低压转子不平衡激励、高压转子不平衡激励、风扇气动激励以及随机噪声的振动能量.