| 1. |
- Bécoulet, A., et al.
(författare)
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Science and technology research and development in support to ITER and the Broader Approach at CEA
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10
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Tidskriftsartikel (refereegranskat)abstract
- In parallel to the direct contribution to the procurement phase of ITER and Broader Approach, CEA has initiated research & development programmes, accompanied by experiments together with a significant modelling effort, aimed at ensuring robust operation, plasma performance, as well as mitigating the risks of the procurement phase. This overview reports the latest progress in both fusion science and technology including many areas, namely the mitigation of superconducting magnet quenches, disruption-generated runaway electrons, edge-localized modes (ELMs), the development of imaging surveillance, and heating and current drive systems for steady-state operation. The WEST (W Environment for Steady-state Tokamaks) project, turning Tore Supra into an actively cooled W-divertor platform open to the ITER partners and industries, is presented.
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| 2. |
- Lu, P. F., et al.
(författare)
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Electronic and optical properties of InGaAs/GaAs quantum dots with tunable aspect-ratio
- 2014
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Ingår i: Modern Physics Letters B. - : World Scientific Pub Co Pte Lt. - 0217-9849 .- 1793-6640. ; 28:9
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a combined approach of finite element method (FEM) and quadratic programming optimization method is proposed to investigate the nonuniform equilibrium composition profile of InGaAs/GaAs quantum dots (QDs) in the framework of Gibbs energy optimization (GEO). The proposed QDs are varied with aspect ratio from 0.3 to 0.5. The wave functions of electron and heavy hole are predicted by using the k . p method. The changes of wave functions before and after optimization can be observed by using composition optimization. Both the eigenvalues and transition energy change obviously with the increasing aspect ratio. The linear optical absorption coefficients corresponding to the interband ground state transition are obtained via the density matrix approach and perturbation expansion method. The numerical results reveal that the aspect ratio and composition profile play significant roles in determining the electronic and optical properties.
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| 3. |
- Zhong, Ziqian, 1995, et al.
(författare)
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Disentangling the effects of vapor pressure deficit on northern terrestrial vegetation productivity
- 2023
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Ingår i: Science Advances. - 2375-2548. ; 9:32
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Tidskriftsartikel (refereegranskat)abstract
- The impact of atmospheric vapor pressure deficit (VPD) on plant photosynthesis has long been acknowledged, but large interactions with air temperature (T) and soil moisture (SM) still hinder a complete understanding of the influence of VPD on vegetation production across various climate zones. Here, we found a diverging response of productivity to VPD in the Northern Hemisphere by excluding interactive effects of VPD with T and SM. The interactions between VPD and T/SM not only offset the potential positive impact of warming on vegetation productivity but also amplifies the negative effect of soil drying. Notably, for high-latitude ecosystems, there occurs a pronounced shift in vegetation productivity's response to VPD during the growing season when VPD surpasses a threshold of 3.5 to 4.0 hectopascals. These results yield previously unknown insights into the role of VPD in terrestrial ecosystems and enhance our comprehension of the terrestrial carbon cycle's response to global warming.
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| 4. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Li, L., et al.
(författare)
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Effect of large magnetic islands on screening of external magnetic perturbation fields at slow plasma flow
- 2017
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1089-7674 .- 1070-664X. ; 24:2
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Tidskriftsartikel (refereegranskat)abstract
- A toroidal resistive magneto-hydrodynamic plasma response model, involving large magnetic islands, is proposed and numerically investigated, based on local flattening of the equilibrium pressure profile near a rational surface. It is assumed that such islands can be generated near the edge of the tokamak plasma, due to the penetration of the resonant magnetic perturbations, used for the purpose of controlling the edge localized mode. Within this model, it is found that the local flattening of the equilibrium pressure helps to mitigate the toroidal curvature induced screening effect [Glasser et al., Phys. Fluids 7, 875 (1975)]-the so called Glasser-Greene-Johnson screening, when the local toroidal flow near the mode rational surface is very slow (for example, as a result of mode locking associated with the field penetration). The saturation level of the plasma response amplitude is computed, as the plasma rotation frequency approaches zero. The local modification of the plasma resistivity inside the magnetic island is found to also affect the saturation level of the plasma response at vanishing flow.
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| 6. |
- Zhang, H., et al.
(författare)
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Effect of High Configuration Entropy and Rare Earth Addition on Boride Precipitation and Mechanical Properties of Multi-principal-Element Alloys
- 2017
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Ingår i: Journal of Materials Engineering and Performance. - : Springer Science and Business Media LLC. - 1059-9495 .- 1544-1024. ; 26:8, s. 3750-3755
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Tidskriftsartikel (refereegranskat)abstract
- A series of multi-principal-element (MPE) alloys have been prepared by adding Ni, Mn, Al, Cu and Y into the reference CoCrFe-B alloy. The microstructure and mechanical properties of these MPE alloys have been investigated thoroughly. It is found that the addition of the elements can inhibit boride precipitation in the designed alloys and the solid solution strengthening effect induced by interstitial boron atoms is more significant than that by boride precipitation. The MPE alloys with the fcc phase as the main solid solution phase have a higher boron solubility and hence less boride precipitation, than those with the bcc phase as the main solid solution phase. The addition of yttrium can improve the boron solubility, decrease boride precipitation, control the boride morphology and, importantly, simultaneously improve the compressive strength and ductility of boron-containing MPE alloys.
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| 7. |
- Zhang, H., et al.
(författare)
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Novel high-entropy and medium-entropy stainless steels with enhanced mechanical and anti-corrosion properties
- 2018
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 1743-2847 .- 0267-0836. ; 34:5, s. 572-579
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Tidskriftsartikel (refereegranskat)abstract
- Novel high-entropy and medium-entropy stainless steels (MESS), containing a high amount of alloying elements, were designed and prepared by arc melting. These high-entropy and MESS possess a simple phase constitution, mainly solid solution phases, and noticeably exhibit excellent anti-corrosion properties in sulphuric acid. In particular, an austenitic Fe 65 Cr 13 Co 4.75 Mn 4.75 Mo 4.75 Ni 4.75 Cu 3 (at.-%) alloy has a higher hardness of 182 HV and better corrosion resistance than those of the 00Cr19Ni14Mn2 austenitic stainless steel prepared under the same condition; a ferritic precipitation hardening Fe 65 Cr 13 Al 3.167 Co 3.167 Mn 3.167 Mo 3.167 Ni 3.167 Ti 3.167 Cu 3 (at.-%) alloy was also developed, with a higher hardness of 584 HV and even better corrosion resistance.
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