首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到8条相似文献,搜索用时 0 毫秒
1.
Lightning strikes are one of the main natural causes of damages to ancient buildings, and have attracted a great deal of attention to the problem of lightning strike disasters. In this study, the lightning strike damage mechanism of ancient building timber and the related damage degrees are investigated, based on the representative timber materials. A lightning-strike simulation device with a 10/350 μs lightning current waveform was adopted for the experiments. The experimental results showed that the lightning strike damages to ancient building timber mainly included timber heating caused by lightning arc heat and current, as well as the air shock wave effects of the lightning, which led to various effect modes under different conditions. The correlations between the damage degree of timber and the water content of timber, timber thickness, as well as the lightning current intensity, are obtained. The current peaks of lightning and the timber water content are the main external and internal causes which influence the damage degrees of ancient timber.  相似文献   

2.
为了验证大型结构体的设计合理性和产品可靠性,掌握结构体负荷承载能力,给出科学评价依据和指导意见,需要科学有效的试验手段为受试对象施加载荷,获取结构体应变、位移等信息,为力学分析提供必要数据支撑。分析了试验平台的主要功能需求,研究了由荷载测控系统、应变测量系统、位移观测系统、试验管理系统和图像监控系统组成的试验平台方案,重点论述了平台的核心关键技术,通过具体应用实例和试验数据,指出了试验平台的应用领域及所能解决的实际问题,最后总结了试验平台的特点和意义。  相似文献   

3.
After the first report of this phenomenon by Apollo 11 astronauts, experiments conducted in space and on the ground confirmed the creation of phosphenes by the interaction of energetic radiation with the human visual system. The aim of this Letter is to show that the energetic radiation generated in the form of X-rays, gamma rays, electrons and neutrons by thunderstorms and lightning is strong enough for the creation of phosphenes in humans. It is also pointed out that some of the visual observations reported during thunderstorms might be attributable to phosphenes excited by this energetic radiation.  相似文献   

4.
5.
采用直径为700nm的二氧化硅微球,通过垂直沉积法在玻璃基片上制备了位于光通讯波段的禁带胶体光子晶体。研究了不同蒸发温度、湿度条件、干燥过程对样品晶体质量的影响。用扫描电子显微镜(SEM)对其形貌进行了观测。实验结果表明,在温度为65℃,相对湿度为70%,缓慢干燥条件下制备出的样品具有较好的晶体质量,晶体在大范围内保持了面心立方(FCC)单晶结构,其(111)面平行于生长基片。  相似文献   

6.
王学水  马贺凯  王岩庆 《大学物理》2011,30(5):43-46,49
介绍了一种新的测量刚体转动惯量的实验方法与实验装置,在实验中,通过增加标准刚体试件,把细线拉力对转轴摩擦力矩的影响考虑进去,大幅度地提高了实验测试精度,另外,利用电力线载波通讯网络,将转动惯量测量仪采集的时间数据传输到PC机中,再经过PC机端数据处理软件,快速准确地将待测刚体的转动惯量以及其它与刚体有关的物理量计算、显...  相似文献   

7.
8.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号