半导和非半导性BaTiO_3陶瓷电声像衬度来源的差异

利用ＳＥＡＭ技术对半导和非半导性的ＢａＴｉＯ３陶瓷材料进行了电声成像观察研究．在半导性的这种材料电声成像中，由于掺杂的作用削弱和屏蔽了样品本身电学性能参数变化对电声像衬度的贡献，使得热波耦合机制起到主要作用；在非半导性的这种材料电声成像中，其电学性能参数的变化决定了电声像衬度的不同．     

THE DESIGN OF A SENSITIVE LOW FREQUENCY COUPLED RESONANT PHOTOACOUSTIC CELL

This paper describes the structure and characters of a coupled resonant photoacoustic cell whichhas a smaller volume and operates at the modulation frequency of several hundred Hz.By the adop-tion of transverse exciting light and differential receiving the detection SNR is increased.Its detec-tion sensitivities for concentration of CH_3OH and C_2H_4 have reached 1.2×10~(-9)/W Hz~(1/2) and4.2×10~(-9)/W Hz~(1/2) respectively.