With the rapid development of modern industries, the high-temperature piezoelectric sensors that can work in extreme environments are in great demand. In this work, langasite (La₃Ga₅SiO14, LGS), as a high-temperature piezoelectric crystal with stable electro-elastic performance, is used as core element, and air and porous Al₂O₃ are selected as backing layers respectively to prepare two kinds of high-temperature acoustic emission (AE) sensors. The detection sensitivities at 25–500^∘C are analyzed by the ball falling test and Hsu–Nielsen experiment. Under the condition of 25–500^∘C, the received amplitude signals by both sensors are maintained above 90dB stimulated by the ZrO₂ ceramic ball dropping. In the Hsu–Nielsen experiment, as the temperature rising from 25^∘C to 500^∘C, the signal amplitude of sensor with air backing layer decays from 447mV to 365mV, while the signal amplitude varies from 270mV to 203mV for the sensor with porous Al₂O₃ backing layer. Significantly, compared with the bandwidth of the air-backing sensor (37–183kHz), the sensor with porous Al₂O₃ backing layer broadens bandwidth to 28–273kHz. These results show that both these AE sensors have strong and stable response ability to AE signals at high-temperature of 500^∘C. Therefore, piezoelectric AE sensor based on LGS has great potential application in the field of high-temperature structural health monitoring.

针对标准泡法在远距离SO₂监测定标不准确的实际问题，开展定标误差校正方法研究。首先，基于标准泡定标法原理以及大气辐射传输理论，提出消除光稀释效应影响的图像校正方法；然后，在充分分析窗片与滤光片反射以及气溶胶散射效应的基础上，对反射效应及散射特性对定标结果的影响进行量化；最后，综合上述影响因素计算得到光稀释效应校正及散射特性修正的定标曲线，并比较误差校正的标准泡定标法与DOAS定标法在反演SO₂柱密度图像以及SO₂排放速率之间差异。结果表明，所提出的校正方法可将标准泡法与DOAS法的定标结果差异从59%降低至7%，验证了该误差校正方法的有效性和准确度。