空间目标态势行为与事件本体设计与构建

针对空间目标态势威胁响应和预警研究不完善的问题，为实现空间目标行为和事件的智能推理、实时响应和主动预警，保障航天活动和空间利益，提出面向行为与事件的空间目标态势本体模型(BEO-SO2)。基于基本形式本体(BFO)，构建空间目标态势行为与事件本体模型。在统一时空框架下建立空间目标关系模型，实现空间目标行为执行和事件发生过程的动态推演。以空间目标碰撞威胁为背景，设计对象实体等级体系和碰撞威胁行为与事件要素，建立碰撞威胁推理规则，基于空间目标态势行为与事件本体进行实现、验证与展示。结果表明,空间目标态势行为与事件本体能够实现空间目标碰撞威胁的等级推理与预警，并指导进一步的空间活动，为航天任务与空间活动提供有效保障。     

Characteristics of solar particle events at Mars relative to Earth

While not specifically designed to detect solar energetic particle radiation, the Electron Reflectometer onboard Mars Global Surveyor (MGS/ER) collected such data from January 1999 through October 2006. Energetic protons (?25 MeV) and other ions penetrated the MGS/ER shielding and registered counts within the instrument’s electronics. During solar particle events (SPE’s), prolonged enhancements in the particle background were observed at Mars with time intensity profiles similar to Earth based SPE observations. Throughout the lifespan of MGS/ER, 85 distinct SPE’s were observed. Basic characteristics of Mars based SPE observations and the frequency of SPE occurrences at Mars are compared to corresponding Earth based observations. Approximately 22% of SPE’s that occurred during MGS/ER operation were observed at Earth but not Mars. Similarly, 19% of SPE’s were observed at Mars but not Earth. Time intensity profiles at Earth and Mars match predictions provided in the literature, based on the physical location of the detector with respect to the motion of the interplanetary shock wave. Note: The work described herein was largely conducted as part of a doctoral dissertation produced by the author.     

Investigations of tip-jet and exhaust jet development in a ducted fan

The major aim of this work is to investigate the tip-jet and exhaust jet development in a ducted fan as well as the impact on the fan’s performance. The flow field of the ducted fans under the solidity varied from 0.2 to 0.7 are simulated by using the shear-stress transport k-ω turbulence model with a refined high-quality structured grid. The exhaust jet trajectory, expanding range and the flow intersection of the jet and mainstream in the blade passage are analyzed. As the results suggest, the flow direction of the exhaust jet is deflected by the downwash and Coanda effect. The major decay region of the exhaust jet can extend at least 2 times the blade chord downstream from the blade trailing edge. The blade circulation is impacted by the tip-jet rather than the exhaust jet from the upstream when the blade tip pitch angle is 8°, and the fan solidity is less than 0.7. The blade tip thrust is reduced by the interruption from the exhaust jet when the blade tip pitch angle is 2°, and the fan solidity is larger than 0.3.     

高温不锈钢的磨削温度测量与烧伤现象分析

针对高温不锈钢1Cr11Ni2W2MoV磨削过程中磨削区内部瞬时温度、磨削表面平均温度的测量方法以及工件表面平均温度与烧伤程度之间的关系进行了研究,分析了工件表面烧伤程度对材料金相组织的影响.通过研究得到了陶瓷结合剂CBN砂轮磨削1Cr11Ni2W2MoV时磨削区内部瞬时温度,证明工件表面的烧伤最直接因素是磨削表面的平均温度,在不同的磨削参数下,表面平均温度超过540℃就形成黄色的微烧伤,随着温度的升高,烧伤程度不断加重.同时,表面烧伤会使马氏体晶格变成细小的退火微晶变质层,烧伤越严重,微晶变质层的厚度越大.     

考虑耦合损伤的燃气轮机叶片材料高低周复合疲劳寿命研究

燃气轮机叶片在实际工作过程中,受到高低周载荷共同作用而易发生疲劳失效.针对高低周复合疲劳损伤演化和寿命预测比较复杂这一问题,考虑高低周载荷叠加形成的耦合损伤,建立了一种新的高低周复合疲劳寿命预测模型,在此基础之上,引入弱化函数描述某些低幅高周载荷对复合损伤的弱化作用,建立了具有低载强化寿命效应的高低周复合疲劳寿命预测模...     

开放式FADEC系统的数据总线研究

研究了容错数据总线这个从集中式向开放式架构过渡的关键技术.在深入研究确定性、一致性、开放性、拓扑结构、调度策略、容错机制和传输带宽等开放式FADEC(全权限数字电子控制)数据总线关键特征的基础上,分析了总线数据传输的时间不确定性问题.从性能、可靠性和可用性的角度深入研究了TTP/C(time-triggered protocol/automotive class C),ARINC659,TTCAN(time-triggered controller area network)和FlexRay这4种时间触发架构数据总线的关键特征.研究结果表明:TTP/C总线是开放式FADEC的最佳选择,最后提出了一种基于TTP/C总线的航空发动机模块化DEEC(digital electronic engine controller)硬件架构.      

一种串并转换器件单粒子效应试验研究

针对型号用新型器件抗辐射能力评估的需要,研制了串并转换器件单粒子效应检测系统,并对卫星型号中准备使用的一款26位串并转换器件进行了单粒子效应评估试验,得到了器件抗单粒子锁定的阈值,并发现该器件在单粒子辐照下会出现连续位输出错误。结合器件版图、结构分析了单粒子效应造成连续位错误的原因,为器件厂家后续设计改进和卫星型号进行系统级抗辐射加固设计提供了依据。     

国产数字信号处理器在轨验证技术研究

文章通过研究某国产数字信号处理器（XX-DSP）体系结构、DSP地面测试方法和空间环境对DSP的典型影响,设计了一种针对国产DSP类器件的在轨验证方法。验证系统硬件平台采用1∶1热备份设计,提高系统可靠性;验证方法借鉴当前地面应用广泛的功能测试方法,覆盖DSP的全部功能单元;另外考虑空间环境中的电离总剂量效应和单粒子效应影响,对DSP的片内RAM和内部寄存器的单粒子翻转（SEU）进行统计,并最终给出单粒子翻转率,同时检测DSP单粒子锁定（SEL）;最后通过运行DSP典型应用算法——有限长单位冲激响应（FIR）滤波算法验证DSP的系统功能,全面考核国产DSP的空间环境适应性。     

航天器单粒子防护薄弱点的识别

针对当前航天器研制中日益突出的单粒子防护量化设计问题,分析了单粒子软错误对航天器影响的特征,建立了评估器件或设备单粒子软错误对航天器影响的危害时间模型,给出了航天器单粒子防护薄弱点的识别方法和步骤,为改进航天器单粒子防护设计提供了客观依据。     

视频处理芯片ADV212单粒子翻转影响分析及故障预案

ANALOG DEVICES公司生产的ADV212可以实现JPEG2000静止图像压缩编码的集成运算,由于其为工业级COMS器件,若用在空间领域,属于单粒子效应的影响对象.文章针对此器件的内部结构和特性,具体分析了其在发生单粒子翻转时所受到的影响,并针对不同的错误类型提出对应的解决措施,形成完整的故障预案.