实时脉冲光声法用于分子弛豫时间的测定(英文)

Real-time pulsed photoacoustics-molecular relaxation time measurements

脉冲光声光谱法一个重要的应用是确定气体分子的振动-平动弛豫时间τV-T.因激光光束的空间分布R(r)对光声测量有显著影响,我们发展了同时测定R(r)和τV-T的方法.本方法基于光声脉冲的实时信号和一种用于光声成像的数学运算法则.本文讨论了智能计算用于多原子气体分子的R(r)和τV-T同时和实时测定的可能性.进一步利用前馈多层神经网络的离线批训练法,结合一个理论光声信号对R(r)和τV-T进行了同时和实时分析.本方法可明显缩短确定上述参数所需时间.

Determination of the vibrational to-translational relaxation time rv-r in gases is one of the applications of pulsed photoacoustic spectroscopy. Because the spatial profile of the laser beam R （r）can significantly influence the accuracy of the photoacoustic measurements, we developed the method for simultaneous determination of the R （r） and rv T. It is based on the temporal shape of the photoacoustic pulse and utilizes a mathematical algorithm developed for photoacoustic tomography. The possibilities of computational intelligence application for simultaneous and real-time determination of R（r）and rv T values of polyatomic molecules in gases by pulsed photoacoustic are also discussed. Feed forward multilayer perception networks are trained in an offline batch training regime to estimate simultaneously,and in real-time,R（r）（profile shape class）and rv x from a given（theoretical）photoacoustic signals. Proposed method significantly shortens the time required for the simultaneous determination of the afore- mentioned quantities.