机内自检和综合诊断技术及其在现代军用飞机上的应用

论述了机内自检技术的概念及在现代开口系统上的应用概况、机内自检技术在保障开口系统的战备守好性所超的作用及在使用过程中所显露出的虚敬率高、论断能力不足、诊断模糊等问题。为了解决这些问题,提出了应采用上前流行的综合诊断技术,同时介绍了综合诊断技术的概念,原理、特点、典型代表及实现方法。     

Intermittent failure process and false alarm interaction modelling of threshold-based monitoring built-in tests (BITs)

Built-in tests (BITs) are widely used in manufacturing and production systems to find whether system failures occur, whereas the problem of BIT false alarms caused by intermittent failures adds to much trouble for the precise failure detection and diagnosis. Fighting with false alarms caused by intermittent failures is an urgent issue. However, the nature and temporal regularity of intermittent failures are not fully exploited, as well as the relationship between intermittent failure and BIT false alarms. The present paper introduces the method of constructing failure test profile for false alarm assessments. Probabilistic models are proposed of the failure evolution process, as well as the interactions between intermittent failures and false alarms. The false alarm time expectation is derived with the given model, serving as the foundation for the optimisation problem to find the best test threshold to enable the highest BIT capability. A numerical analysis is made to illustrate the proposed model and examine the threshold determination method. An application study is also carried out to show how the model can be applicable in real engineering practices.     

装备系统BIT权衡分析与选择技术研究

根据不同的系统结构特性及测试任务需求,机内测试( BIT)存在多种分类方法.首先通过BIT 工作流程分析明确了不同类型BIT之间的关系.然后,针对两种典型的系统级BIT分类方法——BIT运行模式与实现方式的权衡与选择方法进行了系统地研究.对于前者,在系统故障特性分析与BIT测试性指标要求基础上,结合问题特点设计合理的染色体编码方式和适应度函数,并利用遗传算法对BIT运行模式进行权衡与选择；对于后者,通过分析BIT对系统综合保障水平的影响,分别给出相应的定量计算方法,建立基于改进超效率DEA的BIT实现方式权衡与选择计算模型.最后通过案例验证本文所提出方法的可行性和有效性.通过上述分析过程,可以为装备系统BIT详细设计与应用奠定基础.     

利用BIT提高二次雷达系统任务可靠性的新方法

利用一种机内测试( BIT)设计提高了二次雷达系统的任务可靠性,将二次雷达集成系统中原本独立的雷达敌我识别( IFF)和航管( ATC)二次雷达通道变为互备份通道,在一路通道正常的情况下就能成功执行两种二次雷达任务,无需人工干预,切换时间为微秒级,大大提高了任务实时、可靠的完成能力。同时,系统BIT设计中采用了集中-分布式相结合的BIT设计方式,融合两者的优势,完成通道状态的准确判断,能够将故障定位到现场可更换单元( LRU)。这种BIT设计方法的优点在于提高故障检测率的同时有效降低了系统的虚警概率,提高了系统的测试性和维修性;在不增加硬件资源的情况下,提供了一种简单灵活的热备份方法,大大提高了系统的任务可靠性。这种设计方法已成功应用于实际工程,提高了系统的综合性能。     

火控雷达BIT设计研究

现代火控雷达的发展趋势要求系统内部具有BIT能力,本文在分析现代火控雷达发展趋势的基础上,阐述了火控雷达BIT的设计思想,并介绍了具体的实现方法.     

Synthesis, structural analysis and electrochemical performances of BLSITCFx as new cathode materials for solid oxide fuel cells (SOFC) based on BIT07 electrolyte

BaIn_0.3Ti_0.7O_2.85 (BIT07) is a suitable electrolyte for Solid Oxide Fuel Cell (SOFC) but half cells based on La_0.58Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) as a cathode material show a degradation of the Area Specific Resistance (ASR) at 700 °C with time. This study deals with the characterization of alternative cathode materials showing a better compatibility with BIT07 than LSCF. A new solid solution, Ba_xLa_0.58(1−x)Sr_0.4(1−x)In_0.3xTi_0.7xCo_0.2(1−x)Fe_0.8(1−x)O_3−δ, with 0 ≤ x ≤ 1, also called BLSITCFx, with in this case x expressed in molar %, derived from BIT07 and LSCF, has been synthesized at 1350 °C in air using BIT07 and LSCF powders. Two compositions, BLSITCF12 and BLSITCF25, have been selected due to their thermal expansion and conductivity properties. Symmetrical half cells based on these two new materials deposited on BIT07 electrolyte have been studied by complex impedance spectroscopy in air versus temperature and time. Their behaviour is comparable to LSCF's, with ASR values never exceeding 0.2 Ωcm² at 700 °C, and moreover their less important Thermal Expansion Coefficient (TEC) mismatch with BIT07 lead to a better mechanical compatibility with time. These new compounds are therefore better candidates than LSCF as cathode materials for SOFC based on BIT07 electrolyte.     

一种抑制BIT虚警的双限阈值选择与算法实现

本文针对BIT运用中的虚警问题进行了机理分析,并从测试阈值和诊断决策方面入手提出了抑制虚警的措施——双限阈值选择及其算法。双限阈值对应于实际系统的软故障和硬故障,运用概率统计的方法,用详尽的数据和概率图形对该方法进行了详细的理论分析,在满足虚警率远小于百分之一的前提下,找到了相应阈值的选择范围和对应的诊断算法。最后通过实验数据对算法进行了验证,证明了本文所提出的双限阈值选择及其算法实用有效,其思想及结论对其它研究领域亦有借鉴意义。     

高效液相色谱外标法测定杀菌防腐剂BIT

建立了高效液相色谱法测定杀菌防腐剂BIT（1,2-苯并异噻唑啉-3-酮）含量的方法。采用Kromasil C18色谱柱（250×4．6mm）,流动相为甲醇-含0．5mol／L磷酸二氢钾的水溶液（体积比为1：1）;流速为0．6mL／min;紫外检测波长为225nm;外标法定量。样品的平均加标回收率为99．5％-100．10％,相对标准偏差（RSD）为0．20％—0．86％,检出限为0．01mg／kg（S／N=-3）。     

BIT技术的发展现状与应用分析

BIT技术的性能主要从故障探测、故障定位（针对单一的外场可更换单元）、虚假警报、以及错误诊断等方面加以说明。对于正确隔离故障来说，BIT所制定的目标会随着BIT等级的不同而有所变化。BIT等级越低，正确隔离故障的总体能力就越低；BIT等级越高，正确隔离故障的总体能力就越高。     

测试技术与军机维修体制变革

近年来，随着测试技术飞速发展及其在航空领域的应用，特别是ATE和BIT技术的日益成熟，测试设备性能逐步提高，使军机维修工作有了很大变化。同时军机维修体制的变革也不断进行，其中两级维修的实现即为一项重大进步，从美军F-22和F-35飞机成功实施两级维修可知，维修体制变革与测试技术的发展分不开．