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一种非接触式微小飞片速度原位测量技术 被引量:2
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作者 牛锦超 龚自正 +4 位作者 陈荣 曹燕 李宇 杨继运 夏开文 《航天器环境工程》 2013年第4期426-430,共5页
文章提出了一种新的微小飞片平均速度原位测量技术,并研制了速度测量装置。在飞片的飞行路径上设置片激光,通过测量飞片经过片激光的时间间隔及对应的飞行距离,便可获得飞片的平均速度。测量装置的主要部件是高频激光器和高灵敏度光电... 文章提出了一种新的微小飞片平均速度原位测量技术,并研制了速度测量装置。在飞片的飞行路径上设置片激光,通过测量飞片经过片激光的时间间隔及对应的飞行距离,便可获得飞片的平均速度。测量装置的主要部件是高频激光器和高灵敏度光电接收器,无其他复杂或者大型设备,易于与激光驱动微小飞片发射装置等配套衔接,操作方便,成本低。大量试验数据表明,测量装置工作稳定可靠,对厚度不小于3μm、速度不大于10 km/s的飞片,速度测量精度优于5%。 展开更多
关键词 激光驱动飞片 飞片速度 速度原位测量 非接触式测速装置
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Relationship between in situ sound velocity and granular characteristics of seafloor sediments in the Qingdao offshore region
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作者 张严心 郭常升 +2 位作者 王景强 侯正瑜 陈文景 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第3期704-711,共8页
The sound velocity of seafloor sediments from shallow seas can provide important information for harbor design, and ocean and seacoast engineering projects. In this study, in situ measurements were used to obtain accu... The sound velocity of seafloor sediments from shallow seas can provide important information for harbor design, and ocean and seacoast engineering projects. In this study, in situ measurements were used to obtain accurate sediment sound velocities at 45 stations offshore of Qingdao. The relationships between the sound velocity and granular properties of the seafloor sediments were analyzed. Sound velocity showed an increase with the sand content, sand-clay ratio, and sorting coefficient; and a nonlinear decreasing trend with increasing mean grain size and clay content. We plotted a sound velocity distribution map, which shows that the sound velocity was closely related to the geological environment. Previous empirical equations suggested by Hamilton, Anderson, and Liu were used to calculate the velocity with grain size. A comparison between the measured and calculated velocities indicates that the empirical equations have territorial limitations, and extensive data are essential to establish global empirical equations. Future work includes the calibration of the laboratory acoustic measurements with an in situ technique. 展开更多
关键词 sound velocity granular properties empirical equation
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