Gas-coupled acoustic techniques show advantageous capability in analyzing gas mixtures. It is still a challenge to identify the intrinsic characteristics of gas compositions from the acoustic measurements. In this work, we propose an acoustic method to extract the intrinsic internal specific heat of gas composition from molecular relaxation for gas sensing. The internal specific heats of multi-relaxation process in a gas mixture are fast synthesized using measurements of sound speed and absorption at several fixed frequencies. The relative change of internal specific heat due to variation of environmental temperature is employed to identify gas species, and the ratio of the internal specific heat of mixture to that of corresponding pure gas determines the composition concentration. The robustness of the proposed gas sensing method is validated with multi-component mixtures. The acoustic sensing method provides an effective route to identify the intrinsic characteristics of gas compositions in unknown complex gas mixtures.

气体耦合声学技术在分析气体混合物中显示出优越的能力。从声学测量中识别气体成分的内在特征仍然是一个挑战。在这项工作中，我们提出了一种声学方法，可以从分子弛豫中提取气体成分的固有内部比热，以进行气体传感。使用多种固定频率下的声速和吸收率测量，可以快速合成气体混合物中多弛豫过程的内部比热。使用由于环境温度变化而引起的内部比热的相对变化来识别气体种类，并且混合物的内部比热与相应的纯气体的内部比热之比决定了组成浓度。所提出的气体传感方法的鲁棒性已通过多组分混合物得到验证。声波传感方法提供了一种有效的途径，可以识别未知复杂气体混合物中气体成分的内在特征。