| 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. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Aalbers, J., et al.
(författare)
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A next-generation liquid xenon observatory for dark matter and neutrino physics
- 2023
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 50:1
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Forskningsöversikt (refereegranskat)abstract
- The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector.
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| 4. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 5. |
- Cao, H. W., et al.
(författare)
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First-principles study on electronic and magnetic properties of (Mn,Fe)-codoped ZnO
- 2014
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853. ; 352:1, s. 66-71
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Tidskriftsartikel (refereegranskat)abstract
- First-principle calculations have been performed to investigate the electronic and magnetic properties of (Mn,Fe)-codoped ZnO within the generalized gradient approximation (GGA) and GGA+U schemes. The formation energy of five different configurations is investigated and the ground state is demonstrated to be ferromagnetic ordering. By applying the U correction, the band gap energy of pure ZnO is close to the experimental values, while the ferromagnetic ordering of the ground state remains unchanged. The ferromagnetic stabilization is mediated by double exchange mechanism. In addition, defects corresponding to Zn-vacancy and O-vacancy cannot enhance the ferromagnetism obviously. These results indicate that (Mn,Fe)-codoped ZnO are promising magneto-electronic and spintronic materials. (C) 2013 Elsevier B.V. All rights reserved
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| 6. |
- Cao, H. W., et al.
(författare)
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Magnetic properties in (Mn,Fe)-codoped ZnO nanowire
- 2013
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 548, s. 480-484
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Tidskriftsartikel (refereegranskat)abstract
- Using the first-principles density functional theory, we have studied the electronic structures and magnetic properties of Mn/Fe codoped ZnO nanowires systematically. The calculated results of formation energy indicate that the configuration of the lowest energy where Mn and Fe atoms form nearest neighbors on the outer cylindrical surface layer along the [0001] direction, will be determined. The magnetic coupling of 8 types of Mn/Fe codoped ZnO nanowires was investigated and ferromagnetic state was found in certain configurations. The mechanism is from the fierce hybridization between 3d of Mn and Fe with O 2p near the Fermi level. The relative energy difference for configuration VIII is 0.221 eV, which indicates that room temperature ferromagnetism could be obtained in such a system and Mn/Fe codoped ZnO nanowires are a promising nanoscale spintronic material. (C) 2013 Elsevier B. V. All rights reserved.
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| 7. |
- Chen, Hao, 1988, et al.
(författare)
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A Permanent Magnet Brushless Doubly-Fed Electric Machine for Variable-Speed Constant-Frequency Wind Turbines
- 2023
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Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 70:7, s. 6663-6674
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Tidskriftsartikel (refereegranskat)abstract
- A permanent magnet brushless doubly-fed electric machine is presented in this paper. This machine is developed for variable-speed constant-frequency wind energy generation applications. Differing from conventional doubly-fed electric machines based on induction machines, a permanent magnet rotor provides the magnetic field excitations for both the control winding and the power winding in the presented machine. The operating principle of the presented machine for the variable-speed constant-frequency operation is revealed in detail. Compared to a counterpart machine, the presented machine exhibits significantly improved back- electromotive force, torque/power density, torque per magnet volume, efficiency, etc. Finally, a proof-of-concept prototype of the presented machine is fabricated, and the corresponding experimental results are provided to verify the fact that the presented machine is capable of achieving the variable-speed constant-frequency function.
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| 8. |
- Chen, Hao, 1988, et al.
(författare)
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Comparative Study and Design Optimization of a Dual-Mechanical-Port Electric Machine for Hybrid Electric Vehicle Applications
- 2022
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 71:8, s. 8341-8353
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Tidskriftsartikel (refereegranskat)abstract
- A new dual-mechanical-port (DMP) electric machine for hybrid electric vehicle applications, particularly in the power-split continuously variable transmission systems, is proposed in this paper. In order to comprehensively and quantitatively evaluate the pros and cons of the proposed machine, a comparative study of four DMP electric machines with different topologies is conducted. These four investigated DMP electric machines include a conventional DMP machine, a DMP machine with spoke-type permanent magnets, a DMP machine with reluctance rotor, and a DMP machine with open slots which is the proposed machine in this paper. Even though these four machines have similar topologies, they have different operating principles, which are demonstrated in detail. The comparison results indicate that the DMP machine with open slots outperforms the others in terms of torque/power density, efficiency, magnet utilization, etc. Accordingly, the DMP machine with open slots is selected for further investigation and optimization. A large-scale multi-objective optimization is carried out for this machine, where the differential evolution algorithm serves as a global search engine to target optimal performance. Finally, an optimal design is prototyped, and the experimental results are performed to verify the effectiveness of the analysis and simulation results in this paper.
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| 9. |
- Chen, Hao, 1988, et al.
(författare)
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Design and Analysis of a Variable-Speed Constant-Amplitude Wind Generator for Stand-Alone DC Power Applications
- 2023
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Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 70:8, s. 7731-7742
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Tidskriftsartikel (refereegranskat)abstract
- This article presents the design and analysis of a permanent magnet (PM) wind generator, which consists of two sets of windings, and two rotors. The proposed PM wind generator is designed for variable-speed constant-amplitude voltage operation in dc power applications, in order to maximize the utilization of wind energy and make the electricity more accessible to stand-alone situations, e.g., remote areas and offshore islands. The operating principle of the variable-speed constant-amplitude voltage operation of the proposed PM wind generator is demonstrated in detail. A comparative study is carried out among the proposed generator, a conventional surface-mounted PM synchronous generator, and an existing counterpart generator used for the same application. The results show that compared to the conventional PM synchronous generator and the existing counterpart, the proposed PM wind generator exhibits the advantages of high induced voltage, high torque/power density, high efficiency, etc. Finally, the proposed PM wind generator is prototyped and manufactured. The validity of the variable-speed constant-amplitude operation of the proposed generator under both steady-state and dynamic conditions, is verified by experimental results.
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| 10. |
- Ding, L., et al.
(författare)
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Bismuth alloying properties in GaAs nanowires
- 2013
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 205, s. 44-48
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Tidskriftsartikel (refereegranskat)abstract
- First-principles calculations have been performed to investigate the structural, electronic and optical properties of bismuth alloying in GaAs nanowires. A typical model of Ga31As31 nanowires is introduced for its reasonable band gap. The band gap of GaAs1-xBix shrinks clearly with the increasing Bi concentration and the band edge shifts when spin-orbit coupling (SOC) is considered. The insertion of Bi atom leads to hybridization of Ga/As/Bi p states which contributes a lot around Fermi level. Scissor effect is involved. The optical properties are presented, including dielectric function, optical absorption spectra and reflectivity, which are also varied with the increasing of Bi concentrations.
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