Browsing by Author "Chen, G. Y."

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Quantum-dot exciton dynamics with a surface plasmon: Band-edge quantum optics
(2009-03-01)
Chen, Y. N.
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Chen, G. Y.
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Chuu, D. S.
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Brandes, T.
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電子物理學系
We examine the spontaneous emission of a two-level emitter, quantum-dot exciton, into surface plasmons propagating on the surface of a cylindrical nanowire. The numerically obtained dispersion relations are found to influence the spontaneous emission rate strongly. At certain values of the exciton band gap, the emission rates can go to infinity due to the band-edge feature of the dispersion relations. Borrowing the idea from the photonic crystals, we model the quantum-dot exciton dynamics with a non-Markovian way and demonstrate that the decay can undergo an oscillatory behavior. In addition, we also show that the remote entangled states can be generated via super-radiance by using the one-dimensional propagating feature of the nanowire surface plasmons.
Transient solution for radial two-zone flow in unconfined aquifers under constant-head tests
(2010-05-30)
Chang, Y. C.
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Yeh, H. D.
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Chen, G. Y.
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環境工程研究所
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Institute of Environmental Engineering
The constant-head test (CHT) is commonly employed to determine the aquifer parameters. This test is also applied to many environmental problems such as recovering light nonaqueous phase liquids (LNAPL) and controlling off-site migration of contaminated groundwater in low-transmissivity aquifers. A well skin near the wellbore may be produced due to the well construction or development and its formation properties are significantly different from the original ones. A more appropriate description for the skin effect on the aquifer system should treat the well skin as a different formation instead of using a skin factor. Thus, the aquifer system becomes a two-zone formation including the skin and formation zones. This study presents a mathematical model developed for analyzing a two-zone unconfined aquifer system and the associated solution for CHTs at partially penetrating wells under transient state. The solution of the model may be used either to identify the in situ aquifer parameters or to investigate the effects of the wellbore storage and well skin on the head changes in unconfined aquifers under constant-head pumping. Copyright (C) 2010 John Wiley & Sons, Ltd.