| Popis: |
The quartz crystal microbalance (QCM) is a quartz crystal resonator vibrating in thickness-shear mode, in which a minute mass is measured in terms of the resonant frequency change as an mass loading on the resonator surface decreases the resonant frequency [1]. In most applications, however, an adsorbing film layer is formed on the surface, which adsorbs the micro-mass material. The presence of the thin film affects not only the resonance but also its damping, which can not simply be ignored in most QCM applications [2]. That is, the film should be considered as a viscoelastic layer, which must be included in the modeling. In the present paper, the viscoelastic layer is characterized from the measurement of the multiple resonant frequencies and the corresponding resonant resistance by virtue of the overtone operation of the quartz crystal plate. |
