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- Chen, L., et al.
(författare)
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Analysis for the propagation of evanescent waves and the photo tunneling effect in a multi-layered structure containing materials with negative refractive index
- 2003
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Ingår i: Wuli xuebao. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 52:10, s. 2386-2392
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Tidskriftsartikel (refereegranskat)abstract
- The propagation properties of evanescent waves in a multi-layered structure containing materials with negative refractive index are analyzed. The decay or magnification of the amplitude of evanescent waves in different situations is explained analytically in detail. In particular, the influence of the dissipation of the negative refractive index medium on the photon tunneling effect is discussed. The propagation and energy storage of evanescent waves are shown clearly by using the incidence of a Gauss beam.
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| 2. |
- Lu, W., et al.
(författare)
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Application of combinatorial material chip method on the improvement of quantum dots emission efficiency
- 2004
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Ingår i: Proceedings of the SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 5277:1, s. 99-108
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Konferensbidrag (refereegranskat)abstract
- The combinatorial material chip method has been used to study the emission efficiency of InAs/GaAs quantum dots. The photoluminescence spectroscopy is performed to obtain the rule of emission efficiency on the proton implantation dose. A pronounced enhancement of room temperature emission efficiency has been obtained by the optimized quantum dots process condition. The increment of emission efficiency up to 80 itmes has been observed. This effect may be resulted from both the proton passivation and carrier capture enhancement effects. The maximum photoluminescence peak shift is about 23 meV resulted from the intermixing of quantum dots. A linear dependence behavior has been observed for both the non-radiative recombination time and carrier relaxation time on the ion-implantation dose. The maximum enhancement of the photoluminescence is observed in the proton implantation dose of 1.0 x 1014 cm-2 followed by rapid thermal annealing at 700°C. These effects will be useful for the QDs' optoelectronic devices.
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| 5. |
- Ackermann, N.L., et al.
(författare)
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Local scour around circular piers under ice covers
- 2002
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Ingår i: Ice in the environment. - Dunedin : Dep. of Physic, Univ. of Otago. - 1877139521 ; , s. 149-155
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Konferensbidrag (refereegranskat)abstract
- This paper presents a laboratory investigation on the effect of ice cover on local scour around circular bridge piers. Experiments were performed in a 12-meter flume with recirculating sediment discharge. Both smooth and rough artificial covers were used. The bed material consisted of uniform ripple-forming sand. The tests were run for both clear water as well as live bed conditions. The results showed that for equivalent averaged flow velocities the existence of an ice cover could increase the local scour depth scour by 25 to 35 % from the free surface condition. The largest difference occurs at a live bed condition when the flow velocity, U, is in the rage of 1.5 to 2 times of the critical velocity for bed movement, U (sub c) . A rough cover gives slightly larger scour depth than a smooth cover. The movement of bed forms led to variations of scour depth with time.
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