高速飞行器复合材料隔热层参数化设计

以航天飞行器的复合材料隔热层为研究对象,提出了基于遗传算法和有限元(FEA)参数化分析的优化设计方案.其中,以遗传算法为优化方式,基体材料层、隔热材料层、耐烧蚀陶瓷层的厚度为设计参数,隔热层的组合厚度及各层热应力为优化目标;优化过程中调用ANSYS软件对种群中个体进行有限元参数化分析,并将分析结果返回遗传算法程序中构造...     

定子绕组诊断的分离电压和电流正负序分量法

感应电机早期定子绕组故障表现不明显,并且受到电源和负载等外部条件的影响而难以准确检测,如瞬时功率分解法受转子转速、电流波动和电源频率影响较大;对称分量法处理定子绕组不对称问题的效果不理想;同步速坐标变换法计算复杂.为此引入了分离定子电压和电流正负序分量的方法来提取故障特征.采集到的数据先进行低通滤波处理,减弱高次谐波和噪声的影响.采用电源变换消除对负序分量来源的判断;Park 变换将信号从三维坐标转换到二维坐标中;Hilbert变换的频率相移特性可以分离信号的正负序分量.仿真结果表明:该方法可以消除其他非故障因素的影响,准确提取定子电压和电流的正负序分量,并可根据电源的不对称度,分别采用定子负序电流和负序阻抗来表征故障的严重程度.该方法解决了早期定子绕组故障检测的难题,可应用于实际工程中.     

基于平衡流形展开模型的涡扇发动机传感器容错控制

基于某型涡扇发动机平衡流形展开模型设计了一种传感器容错控制方案。首先,利用非线性系统平衡流形建模理论建立某型涡扇发动机性能仿真模型。然后,利用该模型在线估计传感器输出,并根据解析冗余方法,重构故障传感器的输出。最后,针对传感器常见典型故障进行了故障容错控制过程仿真。仿真结果表明,所研究的方法能及时、有效的检测到故障传感器,并实现容错控制,表明该方案的可行性。     

Diagnosis of leakage faults with I DDQ

Recently there has been renewed interest in fault detection in static CMOS circuits through I _DDQ monitoring. This work shows that, in addition to fault detection, accurate fault diagnosis may be performed using a combination of current and voltage observations. The proposed system combines a simple single fault model for test generation with a more realistic multiple defect model for diagnosis, and as a result requires only minor modifications to existing stuck-at fault ATPG software. The associated hardware is sufficiently simple that on-board implementation is possible. Experimental results demonstrate the effectiveness of the method on a standard-cell ASIC.     

Algorithms for I DDQ measurement based diagnosis of bridging faults

In the absence of information about the layout one is left with no alternative but to consider all bridging faults. An algorithm for diagnosis of a subset of such faults, viz. single two line bridging faults in static CMOS combinational circuits is presented. This algorithm uses results from I _DDQ measurement based testing.Unlike known diagnosis algorithms, this algorithm does not use fault dictionaries, it uses only logic simulation and uses no fault simulation. It also uses SOPS, a novel representation of subsets of two-line bridging faults resulting in an efficient algorithm.In spite of the large number of faults that we consider, our experimental results point to the computational feasibility of I _DDQ Measurement based diagnosis of single two line bridging faults. It also shows the effectiveness of reducing the set of possible faults using I _DDQ measurements.A preliminary version of this work was presented at the 29th ACM/IEEE Design Automation Conference, 1992.Research Partially Supported by NSF Grant No. MIP-9102509.This work was performed when the author was with the Dept. of Computer Science, State University of New York at Buffalo.     

雷达发射机高电压绝缘的分析和实践

根据分子运动理论对真空管雷达发射机中高压引起的放电、打火、击穿的过程和因素进行分析,并根据工程实践经验给出高压电源及高压变压器研制时的注意事项,对各种真空管发射机的设计有普遍意义。     

TiO2/MXene-Assisted LDI-MS for Urine Metabolic Profiling in Urinary Disease

Cancer remains an intractable medical problem. Rapid diagnosis and identification of cancer are critical to differentiate it from nonmalignant diseases. High-throughput biofluid metabolic analysis has potential for cancer diagnosis. Nevertheless, the present metabolite analysis method does not meet the demand for high-throughput screening of diseases. Herein, a high-throughput, cost-effective, and noninvasive urine metabolic profiling method based on TiO₂/MXene-assisted laser desorption/ionization mass spectrometry (LDI-MS) is presented for the efficient screening of bladder cancer (BC) and nonmalignant urinary disease. Combined with machine learning, TiO₂/MXene-assisted LDI-MS enables high diagnostic accuracy (96.8%) for the classification of patient groups (including 47 BC and 46 ureteral calculus (UC) patients) from healthy controls (113 cases). In addition, BC patients can also be identified from noncancerous UC individuals with an accuracy of 88.3% in the independent test cohort. Furthermore, metabolite variations between BC and UC individuals are investigated based on relative quantification, and related pathways are also discussed. These results suggest that this method, based on urine metabolic patterns, provides a potential tool for rapidly distinguishing urinary diseases and it may pave the way for precision medicine.     

用于软X射线光刻的等离子体源及干涉诊断分析

阐述了等离子体的产生机理和影响软 Ｘ 射线产生的因素,利用产生软 ｘ 射线的实验系统,分析了软ｘ 射线转换效率与原子数的关系及其空间相干性。给出了等离子体的干涉诊断方法及几个重要的结论。     

“伤寒派”腹诊法在男科疾病中的应用举隅

摘 要:中医腹诊理论源于《内经》《难经》,发展于仲景《伤寒杂病论》。日本汉方医以《伤寒杂病论》为基础形成了“伤寒派”腹诊。“伤寒派”腹诊法相对客观,尤其对于诊查气、血、水异常及兼夹时更有优势,且可一定程度上提示处方用药。而男科疾病恰有多郁、多瘀、多痰及相兼同病等特点,“伤寒派”腹诊法用于常见男科疾病诸如不射精、阳痿、早泄等的辨治取得了较好疗效。     

基于BP神经网络的某型飞机火控系统故障诊断

根据某型飞机火控系统的特点,给出了BP神经网络数学模型及其学习算法,在此基础上以某型飞机火控系统作为为被诊断对象,运用BP神经网络数学模型及其学习算法对其进行故障诊断。诊断结果表明BP神经网络不仅能识别出样本自身的故障,而且能准确诊断出样本以外数据故障,提高某型飞机火控系统一线维修保障效率。