| 1. |
- Börjesson, Gunnar, et al.
(författare)
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A national landfill methane budget for Sweden based on field measurements, and an evaluation of IPCC models
- 2009
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Ingår i: Tellus, Series B: Chemical and Physical Meteorology. - : Stockholm University Press. - 1600-0889 .- 0280-6509. ; 61:2, s. 424-435
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Tidskriftsartikel (refereegranskat)abstract
- Seven Swedish landfills were investigated from 2001 to 2003. On each landfill, a measure of the total methane production was calculated from data on: (1) methane emissions (leakage); (2) methane oxidation and (3) from gas recovery. Methane emissions were determined via a tracer gas (N2O) release-based remote sensing method. N2O and CH4 were measured with an Fourier Transform infrared detector at a distance of more than 1 km downwind from the landfills. Methane oxidation in the landfill covers was measured with the stable carbon isotope method. The efficiency in gas recovery systems proved to be highly variable, but on an average, 51% of the produced landfill gas was captured. A first-order decay model, based on four fractions (waste from households and parks, sludges and industrial waste), showed that the use of a degradable organic carbon fraction (DOCf) value of 0.54, in accordance with the default value for DOCf of 0.50 in the latest IPCC model, gave an emission estimate similar to the official national reports.
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| 2. |
- Lim, J.J., et al.
(författare)
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Static and dynamic performance optimization of a 1.3 µm GaInNAs ridge waveguide laser
- 2008
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Ingår i: 2008 International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD'08; Nottingham; United Kingdom; 1 September 2008 through 4 September 2008. - 9781424423071 ; , s. 121-122
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Konferensbidrag (refereegranskat)abstract
- In this work, we optimise the structure of an uncooled directly modulated 1.3 μm GaInNAs ridge waveguide laser for high temperature operation. The static and dynamic performance of the optimised design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The optimised structure Is shown to have a lower threshold current, higher efficiency, higher modulation bandwidth and lower vertical beam divergence compared to a reference structure with a conventional design. Large-signal 10 Gbit/s digital modulation simulations were performed and demonstrate the improved performance of the optimised structure especially under high temperature operation.
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| 3. |
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| 4. |
- Lim, Jun, et al.
(författare)
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Static and dynamic performance optimisation of a 1.3 mu m GaInNAs ridge waveguide laser
- 2008
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Ingår i: Optical and Quantum Electronics. - : Springer Science and Business Media LLC. - 0306-8919 .- 1572-817X. ; 40:14-15, s. 1181-1186
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we perform a multi-parameter design study to improve the performance of an uncooled directly modulated 1.3 mu m GaInNAs ridge waveguide laser for high speed operation especially at high temperature. The static and dynamic performance of the improved design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The improved structure is shown to have a lower threshold current, higher thermal roll-over limit and higher modulation bandwidth-especially under high temperature operation. The improved structure also has a lower vertical beam divergence compared to a reference structure with a conventional design.
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