纳米薄膜脉冲激光沉积技术

简要介绍了脉丫激光薄膜沉积（PLD）技术的物理原理、独具的特点，介绍了在PLD基础上结合分子束外延（MBE）特点发展起来的激光分子束外延（L－MBE），以及采用L－MBE技术制备硅基纳米PtSi薄膜的结果。     

基于MSG-3的民机维修大纲L／HIRF坊护分析研究

讨论了雷击防护的适航要求,以MSG-3作为分析基础对民用运输类飞机维修大纲L／HIRF防护进行研究,将MSG-3中对于L／HIRF防护的规定分成四个部分进行分析,提出L／HIRF防护敏感度等级、检查间隔以及任务类型确定所采用的方法。本文可为民用飞机初始预定维修大纲的制定提供一定的参考。     

Tolerance of chufa (Cyperus esculentus L.) plants,representing the higher plant compartment in bioregenerative life support systems,to super-optimal air temperatures

Plants intended to be included in the photosynthesizing compartment of the bioregenerative life support system (BLSS) need to be studied in terms of both their production parameters under optimal conditions and their tolerance to stress factors that might be caused by emergency situations. The purpose of this study was to investigate tolerance of chufa (Cyperus esculentus L.) plants to the super-optimal air temperature of 45 ± 1 °C as dependent upon PAR (photosynthetically active radiation) intensity and the duration of the exposure to the stress factor. Chufa plants were grown hydroponically, on expanded clay, under artificial light. The nutrient solution was Knop’s mineral medium. Until the plants were 30 days old, they had been grown at 690 μmol m⁻² s⁻¹ PAR and air temperature 25 °C. Thirty-day-old plants were exposed to the temperature 45 °C for 6 h, 20 h, and 44 h at PAR intensities 690 μmol m⁻² s⁻¹ and 1150 μmol m⁻² s⁻¹. The exposure to the damaging air temperature for 44 h at 690 μmol m⁻² s⁻¹ PAR caused irreversible damage to PSA, resulting in leaf mortality. In chufa plants exposed to heat shock treatment at 690 μmol m⁻² s⁻¹ PAR for 6 h and 20 h, respiration exceeded photosynthesis, and CO₂ release in the light was recorded. Functional activity of photosynthetic apparatus, estimated from parameters of pulse-modulated chlorophyll fluorescence in Photosystem 2 (PS 2), decreased 40% to 50%. After the exposure to the stress factor was finished, functional activity of PSA recovered its initial values, and apparent photosynthesis (P_apparent) rate after a 20-h exposure to the stress factor was 2.6 times lower than before the elevation of the temperature. During the first hours of plant exposure to the temperature 45 °C at 1150 μmol m⁻² s⁻¹ PAR, respiration rate was higher than photosynthesis rate, but after 3–4 h of the exposure, photosynthetic processes exceeded oxidative ones and CO₂ absorption in the light was recorded. At the end of the 6-h exposure, P_apparent rate was close to that recorded prior to the exposure, and no significant changes were observed in the functional activity of PSA. At the end of the 20-h exposure, P_apparent rate was close to its initial value, but certain parameters of the functional activity of PSA decreased 25% vs. their initial values. During the repair period, the parameters of external gas exchange recovered their initial values, and parameters of pulse-modulated chlorophyll fluorescence were 20–30% higher than their initial values. Thus, exposure of chufa plants to the damaging temperature of the air for 20 h did not cause any irreversible damage to the photosynthetic apparatus of plants at either 690 μmol m⁻² s⁻¹ or 1150 μmol m⁻² s⁻¹ PAR, and higher PAR intensity during the heat shock treatment enhanced heat tolerance of the plants.     

燃油气液比对飞机吸力供油的影响研究

吸力供油是民用飞机燃油系统的基本功能,燃油气液状态是影响吸力供油能力的关键性因素。以某型飞机为例,通过严格的试验方法,对吸力供油能力进行了验证,并以试验数据为基础,对燃油气液比进行计算,分析了其产生的影响。研究结果可用于指导飞机燃油系统设计和发动机性能评定。     

单晶高温合金固液界面形状及对凝固组织的影响

ＤＤ８单晶高温合金在高温度梯度宽变速定向凝固装置上进行了单晶定向凝固实验，并在实验基础上系统地分析了凝固条件对固液界面形状及凝固组织缺陷的影响。结果表明，提高冷却速率，限制凝固速率在特定临界速率Ｖ＊以下，可以保持平直的固液界面；当超过这一临界速率Ｖ＊时，固液界面出现下凹，下凹的间液界面将导致形成小角度晶界、显微组织疏松及发散凝固组织，高凝固速率将导致定向凝固过程的个稳定性，制造冷却速率的定向凝固装置是实现快速定向凝固的必要条件。     

大功率高效率星载固态功率放大器研究

针对卫星系统对于微波大功率放大器的需求,研制了L频段200W高效率固态功率放大器,对其设计方法和关键技术进行了详细论述。应用低温共烧多层陶瓷技术,实现了射频电路的高集成和小型化;基于第三代半导体器件,应用波形赋形及线性补偿技术,提升了射频电路的功率和效率;采用移相全桥拓扑,研制了高效率、大功率二次电源。在1.45~1.55GHz的频带范围内,固放整机输出功率大于200W,效率高于60%,3阶交调优于18dBc,同时具备30dB增益可调,360°内步进5.6°的相位可调能力。试验结果表明,该固放为目前国内星载领域连续波功率和效率最高的单机。     

Effects of mineral nutrition conditions on heat tolerance of chufa (Сyperus esculentus L.) plant communities to super optimal air temperatures in the BTLSS

The use of mineralized human wastes as a basis for nutrient solutions will increase the degree of material closure of bio-technical human life support systems. As stress tolerance of plants is determined, among other factors, by the conditions under which they have been grown before exposure to a stressor, the purpose of the study is to investigate the level of tolerance of chufa (Cyperus esculentus L.) plant communities grown in solutions based on mineralized human wastes to a damaging air temperature, 45 °C. Experiments were performed with 30-day-old chufa plant communities grown hydroponically, on expanded clay aggregate, under artificial light, at 690 μmol m⁻² s⁻¹ PAR and at a temperature of 25 °C. Plants were grown in Knop’s solution and solutions based on human wastes mineralized according to Yu.A. Kudenko’s method, which contained nitrogen either as ammonium and urea or as nitrates. The heat shock treatment lasted 20 h at 690 and 1150 μmol m⁻² s⁻¹ PAR. Chufa heat tolerance was evaluated based on parameters of CO₂ gas exchange, the state of its photosynthetic apparatus (PSA), and intensity of peroxidation of leaf lipids. Chufa plants grown in the solutions based on mineralized human wastes that contained ammonium and urea had lower heat tolerance than plants grown in standard mineral solutions. Heat tolerance of the plants grown in the solutions based on mineralized human wastes that mainly contained nitrate nitrogen was insignificantly different from the heat tolerance of the plants grown in standard mineral solutions. A PAR intensity increase from 690 μmol m⁻² s⁻¹ to 1150 μmol m⁻² s⁻¹ enhanced heat tolerance of chufa plant communities, irrespective of the conditions of mineral nutrition under which they had been grown.     

空间目标距离像畸变分析及运动参数估计

针对卫星目标的宽带雷达回波信号,从理论上详细分析了目标运动产生的多项式相位模型,指出三次以上的相位对一维距离像的畸变可以忽略。以频谱主瓣的展宽程度为判据,推导了二次相位需补偿时的目标速度边界条件。结果表明,在典型参数条件下卫星目标的径向速度远大于该临界速度（约560m/s）,需在成像前予以补偿。最后,结合雷达目标散射中心的稀疏分布特性,提出了基于L1范数的空间目标运动参数估计算法。结果表明,该算法对速度的估计误差接近克拉美-罗下界,且远小于临界速度,可用于卫星目标成像。     

含热诱发扰动的挠性卫星L_1自适应控制

为了揭示挠性帆板的热诱发运动机理及其对卫星本体姿态机动的影响,采用拉格朗日能量法建立了主刚体带挠性梁模型受到突加热流时系统的动力学模型,分析了帆板热诱发运动的特性。假设系统的模型参数未知,设计了L1自适应控制器,仅卫星的姿态角和姿态角速度作为反馈量,将帆板热致振动和变形作为未建模动力学特性,实现卫星考虑帆板热扰动力矩的快速姿态机动控制。数值仿真结果表明,环境温度突然变化引起的帆板运动包括准静态变形和振动两部分,同时引起的姿态误差也包括常值偏差和姿态振动,所设计的控制器在系统考虑热引起的扰动时仍可以有效地实现卫星的快速姿态机动,且系统各阶挠性模态稳定,参数估计收敛。     

基于改进半阈值算法的电容层析成像滑油监测方法研究

针对航空滑油检测过程中电容层析成像（Electrical Capacitance Tomography,ECT）存在的病态性和欠定性问题,将稀疏正则化中基于L1/2正则化的半阈值迭代算法应用到ECT图像重建,加入L2范数的惩罚项,构造新的泛函模型,并在迭代过程中设计一种新的约束项以优化解向量。仿真实验采用Comsol5.3搭建系统模型,Matlab2014a处理采集数据。实验结果表明,与Landweber迭代算法相比,改进算法成像误差降低37.33%,相关系数提升33.67%;与半阈值迭代算法相比,改进算法成像误差和相关系数分别降低12.31%和提升11.86%,图像误差降低至0.24、相关系数提升至0.92,且成像时间依然保持在0.06s。实际滑油监测的实验系统采用现场可编程门阵列（Field Programmable Gate Array,FPGA）直接数字频率生成模块生成数字量的正弦激励信号,通过D/A转化为正负交流信号对测量电极进行激励。实验结果表明,基于ECT系统的改进半阈值迭代算法可以满足航空发动机滑油监测的实时性和准确性的要求。