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舰载机机载产品在服役过程中故障率高,故障机理复杂,制约了舰载机作战效能发挥,而传统设计生产阶段的可靠性鉴定试验方法,不能有效推断产品在服役环境下的真实可靠性水平。加速试验是解决高可靠性、小样本产品可靠性评估和验证问题的有效方法,具有低成本、短周期等特征。系统分析了加速试验方法在机载电子产品全寿命周期中的应用现状,包括电子产品加速试验的基本模型、存在问题和发展趋势,从而为有效开展机载电子产品的加速试验提供借鉴。 相似文献
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催化燃烧能提高航空煤油的燃烧效率,其生成的小分子气体也对后期的航空煤油点火燃烧特性起重要作用。以航空煤油一元替代燃料正癸烷为对象,研究了催化燃烧及其气相产物特性,在Pt/ZSM-5和石英砂上进行了催化/无催化燃烧的对比实验,分析了温度 (100~600℃)、当量比 (Φ=0.6/1/2) 和催化剂 (Pt/ZSM-5) 对正癸烷转化率和气相产物特性的影响。研究发现:Pt催化条件下,正癸烷的燃烧启动温度降低约110℃。催化反应在200℃左右就可以实现较高转化率:Φ=0.6~1时,转化率在75%以上。催化反应产物中的CO显著减少,正癸烷转化率和完全氧化程度提高。Φ=0.6~2时,CO2始终是最主要产物。低温下(<150℃)正癸烷催化裂解生成丁烯的反应对催化反应启动有重要影响。烃类气相产物由C3/C4大分子向C1/C2小分子转化和气相氧化产物由CO2向CO转化则是富燃高温(>500℃)下正癸烷催化反应的两个重要特征。 相似文献
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利用HPC系统强大的运算能力和高速数据传输带宽,通过网络互连所构成的网络拓扑结构,再结合基于具有可靠的工作性能和较低的成本,并且具有标准化、同类器件可替换的COTS技术的产品作为计算节点,构建了一种标准化、模块化的软件雷达硬件体系结构。 相似文献
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商用现货器件在卫星中的应用 总被引:1,自引:0,他引:1
在卫星设计过程中,采用商用现货(COTS)电子器件替代传统卫星研制中昂贵的高等级产品来降低研制成本是行之有效的方法。文章总结了商用现货器件在卫星中应用时所面临的空间环境干扰,并针对单粒子翻转问题提出冗余设计和特定电路设计等策略。对当前国内外卫星中采用的各种COTS器件设计方法进行了论述,分析了各种提高商用现货器件可靠度方法的优缺点,并结合已经发射的BIRD、ARGOS等卫星和正在研制的容错结构,综述了COTS器件在卫星中的应用,分析了COTS器件的作用和使用方法。文章内容可为工程实践提供一定的参考。 相似文献
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Mohamed Khalil Ben-Larbi Kattia Flores Pozo Mirue Choi Tom Haylok Benjamin Grzesik Andreas Haas Dominik Krupke Harald Konstanski Volker Schaus Sándor P. Fekete Christian Schurig Enrico Stoll 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(11):3620-3637
Recent developments have seen a trend towards larger constellations of spacecraft, with some proposals featuring constellations of more than 10.000 satellites. While similar concepts for large constellations already existed in the past, traditional satellite deployments hardly ever feature groups of more than 100 satellites. This trend towards considerably larger satellite numbers originates from non-traditional design and operations of spacecraft by non-traditional space companies. The evolution in the space sector, precipitated by new players, is often referred to as “Space 4.0” or “New Space”. It necessitates a rethinking of the way satellites and satellite constellations are planned, designed, and operated. New operational paradigms are needed to enable automatic, optimal task definition, and scheduling in a holistic approach.This is the second of two companion papers that investigate the operations of distributed satellite systems. This second article investigates the classification of distributed satellite systems and evaluates commercial tools for automated spacecraft operations, whereas the first article performed a survey of conventional and “new space”operations of spacecraft constellations.Classification metrics for constellations are derived and evaluated with respect to their informative value concerning the operation, the automation, and the scalability of the constellation. The proposed classification system is applied to the Dove and RapidEye constellation and allows for a comparison between the presented automation approaches. Commercial tools for automated spacecraft operations are evaluated for several mission task elements, such as orbit control, orbit maintenance, and collision avoidance. Subsequently, the trends, benefits, and standardization needs for operational automation are identified. 相似文献
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《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(11):2586-2594
Precise point positioning with ambiguity resolution (PPP-AR) is a useful tool for high-precision geodetic and geophysical applications, while phase bias products are the prerequisite to implement PPP-AR. Wuhan University has been providing the final (the best operationally post-processing solution based) phase clock/bias products with a latency of two weeks since March of 2019, while a dedicated open-source software package PRIDE PPP-AR is released to leverage these products for high-precision positioning. In order to satisfy some both time and precision critical applications, such as rapid earthquake response, Wuhan University also released rapid (with comparable quality but with much shorter delivery latency) phase clock/bias products with a latency of less than 24 h and updated PRIDE PPP-AR in July 2019. We first introduce the phase clock/bias generation and validation schemes and the maintenance of routine products provision. Then, with 14 days (July 2 to July 15 in 2019) of GPS data collected from 146 globally distributed IGS (International GNSS Service) stations, we evaluated the positioning performance of the rapid products with respect to their final counterparts. It is found that positioning precision of PPP-AR using rapid products is comparable to that using final products, especially in kinematic positioning mode. When rapid products are used, the RMS of PPP-AR in static mode with respect to IGS weekly solutions can reach 1.7 mm, 1.8 mm and 5.5 mm in the east, north and up components, respectively. Furthermore, the RMS of epoch-wise positions with respect to daily solutions for the east, north and up components are 0.51 cm, 0.57 cm and 1.51 cm for PPP-AR with rapid products in kinematic mode. It demonstrates that the rapid phase clock/bias products can sufficiently meet the precision requirement of most geodetic and geophysical applications yet with much shorter time delay. Finally, we study the July 6th M7.1 2019 Ridgecrest, California earthquake using the rapid phase clock/bias products and demonstrate their comparable performance against the final products. 相似文献
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为了在Internet网上共享产品数据 ,基于Java语言实现了STEP标准数据读取接口SDAI.该实现包括几个部分 :EXPRESS信息模型向Java语言的映射 ,JavaSDAI会话模式的实现和JOS Part2 1文件、JOS STEP数据库两个映射 .基于该JavaSDAI接口的STEP应用系统 ,可采用Browser Server三层体系结构 ,客户端用户通过通用的Internet网浏览器即可操作异地的STEP产品数据 ,该JavaSDAI接口既与Part 2 1文件又与关系型数据库 (SQLServer)相连接 .通过一个演示实例 ,对JavaSDAI的优、缺点进行了总结 相似文献
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