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171.
采用显微CT(micro-computed tomography)对阻尼器结构分段进行了三维观察,成像分辨率为91.89 μm。通过三维分割成功提取了橡胶层空隙、开裂缺陷,并定量分析空隙缺陷的直径、总体积等几何特征参数。为了提高成像分辨率,对单个空隙缺陷进行局部高分辨显微CT成像及三维可视化分析,获取单个空隙形貌信息。结果表明:黏弹阻尼器以产生脱黏、空隙、开裂缺陷为主,上、下段橡胶层空隙最大直径分别为13.12、12.21 mm,发现上、下段端部存在开裂现象,环状裂纹体向上延伸至橡胶层表面,向下延伸至铝合金内筒外壁。局部显微CT三维成像分辨率为20.85 μm,结果显示单个空隙表面形貌存在褶皱、凹坑现象,但未发现微小裂纹。DR(digital radiography)成像实验结果表明通过X射线切向照相检测黏弹阻尼器橡胶层脱黏、空隙缺陷是可行的。 相似文献
172.
Ji Wu Weiying Sun Jianhua Zheng Cheng Zhang Hao Liu Jingye Yan Chi Wang Chuanbing Wang Shui Wang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Coronal mass ejections (CMEs) represent a great concentration of mass and energy input into the lower corona. They have come to be recognized as the major driver of physical conditions change in the Sun–Earth system. Consequently, observations of CMEs are important for understanding and ultimately predicting space weather conditions. This paper discusses a proposed mission, the Solar Polar Orbit Radio Telescope (SPORT) mission, which will observe the propagation of interplanetary CMEs to distances of near 0.35 AU from the Sun. The orbit of SPORT is an elliptical solar polar orbit. The inclination angle between the orbit and ecliptic plane should be about 90°. The main payload on board SPORT will be an imaging radiometer working at the meter wavelength band (radio telescope), which can follow the propagation of interplanetary CMEs. The images that are obtained by the radio telescope embody the brightness temperature of the objectives. Due to the very large size required for the antenna aperture of the radio telescope, we adopt interferometric imaging technology to reduce it. Interferometric imaging technology is based on indirect spatial frequency domain measurements plus Fourier transformation. The SPORT spacecraft will also be equipped with a set of optical and in situ measurement instruments such as a EUV solar telescope, a solar wind ion instrument, an energetic particle detector, a magnetometer, a wave detector and a solar radio burst spectrometer. 相似文献
173.
非接触式超声兰姆波方法能够对大面积复合材料板材进行快速检测,在自动成像检测上有着突出的优势。针对碳纤维/树脂基复合材料(CFRP)层压板采用空气耦合超声探头激励出A0模态兰姆波。在含冲击损伤的层板试样的同一侧激发和接收兰姆波进行扫描检测,针对冲击损伤区域以互相正交的两个方向进行兰姆波扫查,获得了不同位置的检测信号。对比在有无缺陷处板材中兰姆波传播信号的特征,对采集信号进行频域分析,以无缺陷处信号值为基准,利用信号差异系数(SDC)作为特征值,将扫查信号数据采用特征值全加和全乘的数据融合方法进行了缺陷形貌重构成像。成像结果能够良好的体现出冲击损伤的位置和两个方向的尺寸大小。 相似文献
174.
175.
光从光密媒质射向光疏媒质时,若入射角大于临界角,则发生全反射,但在光疏媒质中仍有电磁波存在,这个电磁波称为消逝波。本文介绍了一种装置,使从光疏媒质一侧成象在界面上的红外象,转换成可见光象,从而间接证明了消逝波的存在;同时探讨了如何利用这种装置构成新型热象仪。 相似文献
176.
In short wavelength case ultrasound propagation through woven carbon fiber-rein-forced composite (CFRC) materials essentially depends on their microstructure.Fiber bundle and weaving ply can be considered as basic structural elements of woven CFRC laminates.These structural units provide effective reflectors when ultra-short impulse high frequency ultrasound impinges on woven laminates.The reflection coefficient R0 achieves level of 3%-15% at ply-ply interface,0.2-0.4 in resin pocket region.This magnitude of reflection coefficient offers reasonable acoustic contrast to see packing,lay-up and resin pockets in woven laminate body by acoustic imaging methods.Microacoustic imaging technique is based on time-resolved echoes from reflections in woven CFRC laminates.A focal system with low aperture angle is used to generate 20-40 probe ultrasonic pulse wave.Its spatial resolution is up to 60mm at 50MHz in woven CFRC laminate.The results presented in this paper demonstrates the possibility and potentiality of characterization of microstrueture of woven CFRC laminates.Packing,lay-up,weaving nature,fiber bundle,resin pocket as well as their topology are exhibited clearly in the acoustic images by using microaeoustic technique. 相似文献
177.
沈笑云 《中国民航学院学报》1994,12(3):50-56
本文介绍了计算机三维成像系统的结构及工作原理,并着重讨论计算机三维成像系统互补色体视图,偏振光体视图及随机点体视图的程序设计方法。 相似文献
178.
179.
T. G. Tsuru T. Tanimori A. Bamba K. Imanishi K. Koyama H. Kubo H. Matsumoto K. Miuchi M. Nagayoshi R. Orito A. Takada S. Takagi M. Tsujimoto M. Ueno H. Tsunemi K. Hayashida E. Miyata 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(12):2688-2690
We propose a new type of wide band X-ray imaging spectrometer as a focal plane detector of the super mirror onboard on future X-ray missions including post Astro-E2. This camera is realized by the hybrid of back illumination CCDs and a back supportless CCD for 0.05–10 keV band, and a Micro Pixel Gas Chamber detecting X-rays at 10–80 keV. 相似文献
180.
Peter W. A. Roming Thomas E. Kennedy Keith O. Mason John A. Nousek Lindy Ahr Richard E. Bingham Patrick S. Broos Mary J. Carter Barry K. Hancock Howard E. Huckle S D. Hunsberger Hajime Kawakami Ronnie Killough T Scott Koch Michael K. Mclelland Kelly Smith Philip J. Smith Juan Carlos Soto Patricia T. Boyd Alice A. Breeveld Stephen T. Holland Mariya Ivanushkina Michael S. Pryzby Martin D. Still Joseph Stock 《Space Science Reviews》2005,120(3-4):95-142
The Ultra-Violet/Optical Telescope (UVOT) is one of three instruments flying aboard the Swift Gamma-ray Observatory. It is designed to capture the early (∼1 min) UV and optical photons from the afterglow of gamma-ray
bursts in the 170–600 nm band as well as long term observations of these afterglows. This is accomplished through the use
of UV and optical broadband filters and grisms. The UVOT has a modified Ritchey–Chrétien design with micro-channel plate intensified
charged-coupled device detectors that record the arrival time of individual photons and provide sub-arcsecond positioning
of sources. We discuss some of the science to be pursued by the UVOT and the overall design of the instrument. 相似文献