Design and Measurement of Quartz Crystal Microbalance as Gas Sensor for Ethyl Alcohol
| Autor: | Yih-Chien Chen, 洪裕杰 |
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| Rok vydání: | 2000 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 88 This search determines the possibility of using Quartz Crystal Microbalance, (QCM) as a gas sensor by measuring its resonant frequency shift in ethanol vapor. For a piezoelectric material, like quartz, the inner dipoles in the crystal would induce electric potential on the surface by mechanical strains, or cause mechanical deformation by electric fields. Because of the piezoelectric effect, an AT-cut quartz crystal vibrates in thickness-shear mode of a certain frequency. The resonant frequency is determined by the thickness of the quartz plate and the mass loading on its electrodes. By measuring the change of resonant frequency of QCM, the physical characteristic of the substance deposes on the surface of the electrodes can be understood. This is the basic principle of a QCM gas sensor. The frequency shift of QCM deposited with stearic acid is six times larger then bare QCM in the experiment. The response time and sensitivity of QCM will be improved by the research of the sensing material, film-deposition technique, and measurement system. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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