提高可靠性数据分析精度的一种有效方法

为更加准确地掌握导弹某部件的寿命规律,提高导弹某部件的可靠性数据处理精度,使得可靠性寿命模型更加符合实际情况,本文指出传统的平均秩次法在计算经验分布函数中存在的不足,提出一种改进的平均秩次法,实例结果证实了改进方法的有效性。     

一种基于弱化算子改进的灰色模型故障预测方法

针对航空装备故障预测需求,在对灰色GM(1,1)基本模型分析研究的基础上,通过引入弱化算子对该故障预测模型进行改进,并以某直升机滑油温度控制盒峰值电压数据为对象进行应用分析,结果表明弱化算子改进模型可降低故障预测误差、提高预测精度;同时,将基于弱化算子改进模型的算法分别与序列平均变化率算子、新陈代谢模型两种算法进行组合,也验证了基于弱化算子改进模型可以提高预测精度,这对提高航空装备故障预判与维修保障能力具有重要参考借鉴价值。     

航空磁探中使用边界元法的潜艇磁场建模

为解决航空磁异常探测中潜艇高空磁场分布难以测量的问题,根据Maxwell方程组和边界元法的基本原理,在预测空间基于格林函数,通过矢势分布求得潜艇空间磁场分布,建立潜艇磁场预测模型。使用磁偶极子仿真潜艇目标对预测模型进行初步理论验证,进一步设计实验对预测模型的有效性进行实际检验。根据理论和实验验证,结果表明,使用边界元法的潜艇磁场预测模型的平均绝对误差为0.220 5 n T,平均相对误差为2.368%。     

考虑退化状态的功率器件寿命预测研究

功率变流器是风机系统的核心组件,其可靠性直接影响风电系统的可靠性。风电变流器中主要的失效部件是IGBT模块,因此对IGBT模块进行寿命预测可以提高整个风电系统的可靠性。首先讨论变流器电热耦合模型中的退化参数,然后基于LESIT寿命预测模型和雨流循环计数法提出考虑IGBT模块退化状态的寿命预测方法。文中以1.2 MW风力发电系统为例,预测了网侧风电变流器中IGBT模块的寿命,并对比分析了是否考虑模块的退化状态对寿命预测结果的影响。     

环氧模塑封材料的热-机械疲劳失效分析

封装材料的热疲劳失效是封装器件失效的主要原因之一。对在微电子封装中应用很广的环氧模塑封装材料进行了常温和高温下的拉伸、疲劳实验。基于以疲劳模量作为损伤因子的疲劳寿命预测模型,相应的材料参数通过实验获得。并通过实验得出了该环氧模塑封装材料考虑温度影响的疲劳寿命预测模型,利用该模型可以对微电子封装用高聚物的疲劳寿命进行预测。     

环氧模塑封材料的热–机械疲劳失效分析

封装材料的热疲劳失效是封装器件失效的主要原因之一.对在微电子封装中应用很广的环氧模塑封装材料进行了常温和高温下的拉伸、疲劳实验.基于以疲劳模量作为损伤因子的疲劳寿命预测模型,相应的材料参数通过实验获得.并通过实验得出了该环氧模塑封装材料考虑温度影响的疲劳寿命预测模型,利用该模型可以对微电子封装用高聚物的疲劳寿命进行预测.     

多核相关向量机优化模型的锂电池剩余寿命预测方法

基于相关向量机的剩余寿命预测方法,核函数是影响相关向量机模型预测性能的重要因素.目前的相关向量机预测模型以单核为主,且核函数的选择存在较大主观性,导致所构建的预测模型性能有限.本文提出一种融合多个核函数构建相关向量机预测模型的方法,通过果蝇算法优化多个核函数优化组合的线性方程系数,提高了模型的预测性能,并将该方法应用于预测锂离子电池的循环剩余寿命.分别采用美国NASA和马里兰大学的电池退化数据集,对本文的方法进行了实验验证.实验结果表明：多核相关向量机预测方法的平均绝对误差和均方根误差都小于最优的单核相关向量机预测方法.     

基于改进SVM与WSN的变电站柜内线缆寿命预测模型设计

针对现有的大多数人工智能模型难以适用于变电站柜内电力线缆寿命预测的问题,文中设计一种基于WSN与改进SVM算法的变电站柜内线缆寿命预测模型。该模型利用无线传感网络构建包含同步相量测量单元的变电站柜内环境数据采集传输系统,并将采集到的数据上传至系统管理中心做进一步分析。同时,采用Rao算法对支持向量机算法加以改进,并将改进后的算法用于预测变电站柜内线缆的寿命。通过对比预测值与安全阈值的数据得到最终识别结果,实现了电缆状态的异常识别,从而辅助工作人员采取相应的措施。基于搭建的测试平台对所提模型进行了实验测试,分析所得到的数据可知,预测结果的ME、RMSE和MAPE值分别为78 h,52 h及2.263%,能够准确地预测变电站柜内线缆的寿命。     

基于YOLOv5的航空发动机部件识别

为了实现快速且高精度的识别航空发动机部件,设计了一种采用YOLOv5算法的航空发动机部件识别方法。使用相机拍摄获取真实航空发动机上的部件原始图片,并使用LabelImg标注工具和数据增强方法自建航空发动机部件数据集,经过YOLOv5s模型训练,获得满意的识别效果。实验结果表明,在真实发动机上进行测试,能够有效地识别13种类别的部件,其平均精准率为90.23%,平均检测速度达到76 FPS,能够在使用增强现实设备时达到实时识别航空发动机部件的要求。     

航空、航天与航海工程

0021443“需求拉动式”航空器材需求预测与控制模式[刊,译,英]/吴桐水//南京航空航天大学学报(英文版).—2000,17(1).—78～83(E)提出了“需求拉动式”航空器材库存控制模式,建立了基于可靠性分析的航空器材需求预测模型。该模型通过对航空器材使用信息进行可靠性分析,得出零件可靠性寿命函数,并根据给定可靠度下的零件寿命预测航空器材需求时间。最后对视情维护下的周转件需求预测与库存控制进行了案例分析。参5     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.