带有等压缓冲器的冲击台

本文介绍了等压式缓冲器及带有等压式缓冲器的冲击台的结构及其工作原理，说明了影响冲击加速度的因素及其调整方法。     

实用换能器频谱及声场特性分析

本文从超声检测原理出发 ,针对超声检测中近场区内缺陷难以准确定量的问题 ,利用计算机数字信号处理技术 ,通过对不同换能器进行频谱分析 ,计算各换能器声轴线上声压分布曲线 ,并进行对比实验 ,探讨了超声检测中声轴线上声压分布的一般规律。为提高超声检测的可靠性 ,并最终解决上述问题提供了理论和实验依据     

美国“阿波罗”飞船的振动试验

文章介绍了美国“阿波罗”飞船的振动试验,包括环境预示、计划制定与试验技术。     

基于磁场映像的印制电路板故障诊断方法研究

简要分析了印制电路板的电磁场，提出了用电磁感应法测量磁场的电咱故障诊断新方法，并给出了测试系统组成方案。最后通过验证实验证明了该方法是确实可行的。     

碳/环氧复合材料两次表面镜基板研制

文章介绍了碳/环氧复合材料两次表面镜基板的结构与铺层、选材与成型工艺,性能测试等内容。     

语言测试及设计

在外语教学中，语言测试是不可缺少的环节之一。本文主要论述语言测试理论，如语言测试的目的、语言测试的类型、语言测试的标准；分析并总结了常见的语言测试项目的设计方法，如：多项选择题的设计、词汇测试的设计、完形测试的设计、阅读理解的设计、听力测试的设计、写作测试的设计；并对测试后得分的计算和分析进行解释。最后提出语言教师了解一点语言测试的知识是很有必要的。     

Visual inspection of aircraft skin: Automated pixel-level defect detection by instance segmentation

Skin defect inspection is one of the most significant tasks in the conventional process of aircraft inspection. This paper proposes a vision-based method of pixel-level defect detection, which is based on the Mask Scoring R-CNN. First, an attention mechanism and a feature fusion module are introduced, to improve feature representation. Second, a new classifier head—consisting of four convolutional layers and a fully connected layer—is proposed, to reduce the influence of information around the area of the defect. Third, to evaluate the proposed method, a dataset of aircraft skin defects was constructed, containing 276 images with a resolution of 960 × 720 pixels. Experimental results show that the proposed classifier head improves the detection and segmentation accuracy, for aircraft skin defect inspection, more effectively than the attention mechanism and feature fusion module. Compared with the Mask R-CNN and Mask Scoring R-CNN, the proposed method increased the segmentation precision by approximately 21% and 19.59%, respectively. These results demonstrate that the proposed method performs favorably against the other two methods of pixel-level aircraft skin defect detection.     

Stability analysis of robotic longitudinal-torsional composite ultrasonic milling

Currently, industrial robots are considered as an alternative towards traditional machine tools. Especially for the large-scale parts milling, robotic flexibility and low cost make it possess the irreplaceability. However, the milling chatter caused by its weak rigidity hampers robotic application and promotion severely in aviation industry. Rotary ultrasonic milling (RUM) technology with one-dimensional axial vibration has been proven and approved on avoiding robotic chatter. Based on this, the research of project team demonstrates that longitudinal-torsional composite ultrasonic milling (CUM-LT) involving separation characteristic has a greater advantage than RUM in terms of chatter suppression. Thereby, the CUM-LT as a new means is applied to avoid processing vibration of robotic milling system. And its influence mechanism on stability improvement of weak stiffness processing system is clarified. Meanwhile, the approaches to strengthen separation effect are provided innovatively. Moreover, a new analysis method of robotic CUM-LT (RCUM-LT) stability is proposed on the basis of ultrasonic function angles. The simulation and experimental results indicate that compared with robotic RUM (RRUM), stability regions of separated RCUM-LT (SRCUM-LT) and unseparated RCUM-LT (URCUM-LT) are improved by 124.42% and 39.20%, respectively. The addition of torsional ultrasonic energy has a wonderful effect on the milling chatter suppression of low stiffness robots.     

基于在线调试的串口通信协议测试方法

以测试某型数据传输数字地图子系统中数字地图生成模块软件的RS485通信协议为例,提出了两种基于在线调试的串口通信协议的测试方法。这两种方法不仅简单易行地解决了某些测试环境中无法利用串口调试工具进行串口通信协议测试的问题,还为软件测试领域提出了一种通过在线调试技术解决问题的思路。     

典型民机复合材料损伤分析及敲击检测

只有充分研究民机典型复合材料损伤机理,才能在复合材料的应用中最大限度地减少和避免其损伤,并且为复合材料的损伤修理奠定基础.通过对民机典型复合材料损伤的研究,分别从材料、设计、结构、制造与使用等方面入手,通过细观破坏机制阐述了层合复合材料的损伤.对部件的检测进行理论分析,找到易损伤位置,采用微观破坏机制运用敲击检测法对胶接复合材料就行了损伤检测,验证了二者的结合可提高检测效率及准确率.