【摘要】 压电光声光谱法研究样品热扩散率的实验中,仪器贡献位相的影响使得实验结果远离理论预测结果。在分析仪器贡献位相产生因素后认为,由于光声池本身引起的位相贡献可以忽略,在同一检测系统内如果保持其他实验条件不变,可按稀土固态配合物配体和中心离子的光声位相计算得到仪器位相贡献,并以铝制样品为参考对热扩散率进行测算。实验结果和真实值的匹配说明在一定频率范围内通过差减仪器贡献位相可以得到比较满意的结果,但在低频率范围,公式的简化没有充分根据,所以带来结果上的偏差。此外,还把压电光声法应用到植物叶片的检测中。并根据实验获得的压电光声仪器贡献位相计算莲花玉兰叶片的热学参数。更多还原

【Abstract】 Piezoelectric photoacoustic phase information can be applied to determine the thermal diffusivity of sample.In actual experiments,the results of phase versus modulation frequency deviate from the theory heavily because of the disturbance of instrumental contribution from the whole detecting system.Considering that the instrumental contribution of phase from PA cell can be ignored reasonably, there will be no additional phase contribution after the piezoelectric PA cell has been replaced by microphone PA cell while the other experimental conditions have been kept invariable.Based on this hypothesis,the conventional photoacoustic cell with microphone is employed to determine the instrumental contribution of whole detecting system by studying the PA phase of solid rare earth complexes.The instrumental contribution of phase was considered to be constant for that the same detecting system was used in both the microphone PA method and piezoelectric PA method.This method has been proved by detecting the thermal diffusivity of aluminium sample.The corrected results of experiments match the theory well,showing that the method of subtracting the instrumental contribution from the original experimental phase can be applied reasonably in relevant chopping frequency region.While in lower chopping frequency region,there will be a little deviation from the theoretical results.The method has been also employed to the photoacoustic detection of leaf,and the thermal diffusivity of leaf can be acquired by studying the piezoelectric photoacoustic phase.更多还原