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- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 7. |
- Jmerik, V.N., et al.
(författare)
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Optically pumped lasing at 300.4 nm in AlGaN MQW structures grown by plasma-assisted molecular beam epitaxy on c-Al2O3
- 2010
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Ingår i: PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE. - : WILEY-V C H VERLAG GMBH. - 1862-6300. ; 207:6, s. 1313-1317
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Tidskriftsartikel (refereegranskat)abstract
- We have demonstrated optically pumped room-temperature pulse lasing at 300.4 nm from an AlGaN-based multiple-quantum-well (MQW) structure grown by plasma-assisted molecular beam epitaxy on a c-sapphire substrate. The lasing was achieved at the threshold peak power of similar to 12 MW/cm(2). The MQW structure involved AlGaN/AlN short-period super-lattices to decrease the threading dislocation densities from 10(11) down to 10(9)-10(10) cm(-2). Studies of time-resolved photoluminescence (TRPL) spectra and cw PL temperature dependences (10-300K) of different MQW structures, as well as numerical calculations of the optical gain and confinement in the laser structure allowed us to conclude about the optimum design of AlGaN-based MQW structures for the lower threshold UV lasing.
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| 8. |
- Shubina, Tatiana, et al.
(författare)
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Recombination dynamics and lasing in ZnO/ZnMgO single quantum well structures
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:20
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Tidskriftsartikel (refereegranskat)abstract
- We report a time-resolved study of the recombination dynamics in molecular beam epitaxy grown ZnOZnMgO single quantum wells (SQWs) of 1.0-4.5 nm width. The SQWs exhibit different emission properties, depending on both the well width and defect density. Stimulated emission has been achieved at room temperature in a separate confinement double heterostructure having a 3 nm wide SQW as an active region. It has been found that a critical parameter for the lasing is the inhomogeneous broadening of both QW and barrier emission bands. © 2007 American Institute of Physics.
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| 9. |
- Bourguignon, J., et al.
(författare)
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Chiral ditopic receptors. Application to palladium-catalyzed allylic alkylation
- 2003
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Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 59:48, s. 9583-9589
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Tidskriftsartikel (refereegranskat)abstract
- Chiral pyridinooxazoline, quinolinooxazoline, bis(oxazolino)pyridine (pybox), and bisoxazoline (box) derivatives containing crown ether residues were prepared. Some of the ligands were assessed in substrate binding studies and in palladium catalyzed allylic alkylations.
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| 10. |
- Bremberg, U, et al.
(författare)
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Rapid and stereoselective C-C, C-O, C-N and C-S couplings via microwave accelerated palladium-catalyzed allylic substitutions
- 2000
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Ingår i: Synthesis (Stuttgart). - Uppsala Univ, Uppsala Biomed Ctr, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. Royal Inst Technol, Dept Chem, SE-10044 Stockholm, Sweden.. - 0039-7881 .- 1437-210X. ; :7, s. 1004-1008
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Tidskriftsartikel (refereegranskat)abstract
- Palladium-catalyzed substitution of cyclohex-2-en-1-yl ethyl carbonate with neutral C-, O-, and N-nucleophiles was achieved in 1-2 minutes using microwave flash hearing. Enantioselectivities up to 96% were observed. Ionic nucleophiles tended to result in lower ee. With S-nucleophiles problems with the stability of the nucleophile were encountered.
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