光纤Bragg光栅液氦环境下温度传感特性的研究

进行了液氦温度（4．2K）到室温（298K）温区内光纤Bragg光栅（FHG）温度传感性能的实验研究。重点分析了液氦温度（4．2K）到液氮温度（77K）FBG的温度传感特性。实验表明：FHG传感特性与温度相关。在50K以下，温度响应基本没有变化；50K-77K，波长偏移量随温度上升变化不规律；150K-298K传感特性近似成线性。对比裸光栅与涂敷光栅，涂敷光栅的温度灵敏度远大于裸光栅的温度灵敏度。选用外加热膨胀系数大的聚合物封装，可以显著提高FHG的温敏系数和线性度。

Single curved fiber sedimentation under gravity

Dynamics of single curved fiber sedimentation under gravity are simulated by using the lattice Boltzmann method. The results of migration and rotation of the curved fiber at different Reynolds numbers are reported. The results show that the rotation and migration processes are sensitive to the curvature of the fiber. (c) 2007 Elsevier Ltd. All rights reserved.