Browsing by Author "Wang, C. P."

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Contact to ZnO and intrinsic resistances of individual ZnO nanowires with a circular cross section
(2007-05-28)
Lin, Yen-Fu
;
Jian, Wen-Bin
;
Wang, C. P.
;
Suen, Yuen-Wuu
;
Wu, Zhong-Yi
Single crystalline ZnO nanowires (NWs) with a circular cross section and similar to 40 nm in diameter have been synthesized and utilized to fabricate two-contact ZnO NW devices. The electrical properties of the NW devices can be categorized into two classes according to the magnitude of their room-temperature resistances. I-V curves of low-resistance devices exhibit downward bending features and their temperature dependent resistances demonstrate thermal activation transport in the ZnO NWs. The high-resistance NW devices can be modeled as back-to-back Schottky contacts and the electron transport through the contacts reveals a variable-range-hopping mechanism. (C) 2007 American Institute of Physics.
Transient behavior of CO poisoning of the anode catalyst layer of a PEM fuel cell
(2006-09-22)
Chu, H. S.
;
Wang, C. P.
;
Liao, W. C.
;
Yan, W. M.
;
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.