Welding-packaged accelerometer based on metal-coated FBG

A fiber Bragg grating-based accelerometer with a fully metalized package is presented. Magnetron sputtering and electroplating techneques are successively adopted to metalize bare SiO 2 fiber with a single Bragg grating. Laser welding techneque is adopted to fix the metal-coated fiber on the sensor component to obtain a fully metallized package without adhesives. Vibration test results demonstrate that the accelerometer has a flat frequency response over a 1-kHz bandwidth, with a resonance frequency of 3.6 kHz, wide linear measurement range of up to 8 g, and sensitivity of 1.7 pm/g .     

EFPI-FBG hybrid sensor for simultaneous measurement of high temperature and large strain

We report an extrinsic Fabry–Perot interferometer-fiber Bragg grating(EFPI-FBG) hybrid sensor in this letter. The interferometric cavity of the proposed hybrid sensor is composed of a glass capillary tube, a section of single-mode fiber, and a section of single-mode metal fiber with one FBG. The FBG processed by high-temperature annealing is used to measure temperature, whereas the fiber EFPI is adopted for strain measurement. One of the two aligned fibers is free along the axial direction, which is different from the traditional structure that both the fibers are fixed to glass capillary tube. Experimental results show that the sensor can measure high temperature and large strain simultaneously. The measuring range of temperature and strain for the hybrid sensor is up to 500 °C and 10,000 με, respectively. Effective temperature compensation of the hybrid sensor is realized, too.     

Hybrid fiber Bragg grating sensor for vibration and temperature monitoring of a train bearing

We report a fiber Bragg grating(FBG)-based sensor for the simultaneous measurement of a train bearing's vibration and temperature. A pre-stretched optical fiber with an FBG and a mass is designed for axial vibration sensing. Another multiplexed FBG is embedded in a selected copper-based alloy with a high thermal expansion to detect temperature. Experiments show that the sensor possesses a high resonant frequency of 970 Hz, an acceleration sensitivity of 27.28 pm/g, and a high temperature sensitivity of 35.165 pm/℃. A resonant excitation test is also carried out that demonstrates the robustness and reliability of the sensor.     

粉尘质量浓度的光纤光栅传感测量技术

粉尘质量浓度是粉尘爆炸的关键因素,针对目前对本质安全、可实时监测预警的粉尘质量浓度测量技术的迫切需求,提出一种基于光纤光栅和光纤准直器的新型测量技术,在阐述其测量理论的基础上,搭建测量和实验装置实物。对200、300和400目这3种粒径规格的小麦粉尘分别开展实验测量,结果表明：所提出的测量技术的光功率输出和粉尘质量浓度呈线性关系;并与标准的称重法得到的粉尘质量浓度开展对比,验证了光纤光栅测量技术的有效性。

     

锂离子电池用酚醛树脂热解炭材料的研究

以酚醛树脂为前驱体制备锂离子电池负极用热解炭材料.采用热失重分析方法研究了酚醛树脂在热处理过程中的变化.采用XRD、BET及电化学方法研究了所得热解炭材料的结构与性能.随着热解温度升高和恒温时间增加,所得热解炭材料的结构有序性增加,比表面积减小,首次充电容量和放电容量均减少,充放电效率增大.其中1050℃下恒温2小时所得热解炭材料的电化学性能较好,首次充电容量、放电容量和充放电效率分别为560mAh/g、387mAh/g、69.1%.