用热图法检查复合材料中粘结层和层间的缺陷

本文报导用液晶热图法对复合材料中粘结层和层间缺陷的检查研究。此法已成功地用于三种复合材料(E 玻璃纤维/环氧、石墨/环氧及 HMC)中缺陷的检查。将热图法的检查结果与超声 C-扫描法相比较,以评价这种新技术的效果。此外,还用显微照相来证实所测得的各种缺陷,并查明实际损伤的类型和大小。     

A Method of Inversing the Peak Density of Atomic Oxygen Vertical Distribution in the MLT Region From the OI (557.7nm) Night Airglow Intensity

In this paper, using the MSISE-90 model as the reference atmosphere, we discuss the feasibility and method of deducing the peak densities of the undisturbed atomic oxygen profiles in the MLT region (the mesosphere and lower thermosphere region) from OI (557.7 nm) night airglow intersities. The peak densities for different seasons, latitudes and longitudes are deduced from OI (557.7nm) airglow intensities through this expression. We analyze the features of inversion relative errors and discuss the influence of the variations in temperature on inversion errors. The results indicate that all inversion errors are less than 5% except for those at high altitudes in the summer hemisphere. And the impact of the variations in temperature on errors is not significant.      

齿轮传动风扇旨在降低费用和简化结构

普惠公司的PW8000发动机的主要特点是采用齿轮传动风扇的结构,这种结构将使发动机的转子级数和叶片数分别比现有相当推力级的常规发动机的少40%和50%.该发动机的初步设计正在进行中,其详细设计在6月以前开始.因此,PW8000的一些特点将在今夏最后确定,预计合格证将从6月份以后用30个月时间取得.对于一种典型的涡扇发动机而言,其高压涡轮驱动高压压气机,而低压涡轮驱动低压压气机和风扇,然而最有效的风扇转速比低压涡轮的转速低,这导致都不是特别有效的折衷转速.对于齿轮驱动的风扇系统而言,减速     

2090Al-Li合金的氢脆

众所周知,在其它传统高强铝合金已观察过的浸蚀环境中,氢气在 Al-Li 合金力学性能降低上扮演着一个重要的角色。在本研究中,通过充氢样品的拉伸试验,检测了氢对2090Al-Li 合金力学性能的影响。在 HCl 溶液中,对拉伸样品采用阴极充氢并在不同的温度和应变速率下进行试验。发现:氢的影响随着充氢的时间增加而增大,但随试验温度下降而减小;还发现:在293K 处,随着应变速率的下降,氢的影响增加。