Browsing by Author "Liao, W. C."

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Measuring junction temperature of GaAs solar cells using pulse-width modulation photoluminescence
(2010-07-01)
Yang, M. D.
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Liao, W. C.
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Shu, G. W.
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Liu, Y. K.
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Shen, J. L.
A photoluminescence (PL) technique is presented to measure the junction temperature of GaAs solar cells. The technique utilizes the pulse-width modulation of excitation laser and the temperature dependence of PL spectra. The apparent change of PL energy on duty cycle can be advantageously used for the determination of the junction temperature. Varying the duty cycle from 10% to 75% causes an increase of 2.9 Kin the junction temperature of GaAs solar cells. The carrier temperature of the junction layer was studied to confirm the result obtained from the pulse-width modulation PL (C) 2010 Elsevier Ltd. All rights reserved.
Transient behavior of CO poisoning of the anode catalyst layer of a PEM fuel cell
(2006-09-22)
Chu, H. S.
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Wang, C. P.
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Liao, W. C.
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Yan, W. M.
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機械工程學系
A one-dimensional transient mathematical model is applied to simulate the carbon monoxide poisoning effect on the performance of a PEM fuel cell. Based on the CO kinetic model developed by Springer et al. [T.E. Springer, T. Rockward, T.A. Zawodzinski, S. Gottesfeld, J. Electrochem. Soc. 148 (2001) A11-A23], the transient behaviors of the CO poisoning process across the anode catalyst layer is investigated. The results show that the hydrogen coverage, OH, decreases with the time due to CO adsorption on the catalyst sites. A higher CO concentration results in fewer available catalyst sites for hydrogen electro-oxidation and a significant decrease in the response time to reach steady state, t(ss). Increasing the anode overpotential and the gas porosity would result in an increase in the current density, especially at low levels of CO concentration. (c) 2006 Elsevier B.V. All rights reserved.