| 1. |
- Fenstermacher, M.E., et al.
(author)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Journal article (peer-reviewed)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 2. |
- Chen, H., et al.
(author)
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Unprecedented non-hysteretic superelasticity of [001]-oriented NiCoFeGa single crystals
- 2020
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In: Nature Materials. - : Nature Research. - 1476-1122 .- 1476-4660.
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Journal article (peer-reviewed)abstract
- Superelasticity associated with the martensitic transformation has found a broad range of engineering applications1,2. However, the intrinsic hysteresis3 and temperature sensitivity4 of the first-order phase transformation significantly hinder the usage of smart metallic components in many critical areas. Here, we report a large superelasticity up to 15.2% strain in [001]-oriented NiCoFeGa single crystals, exhibiting non-hysteretic mechanical responses, a small temperature dependence and high-energy-storage capability and cyclic stability over a wide temperature and composition range. In situ synchrotron X-ray diffraction measurements show that the superelasticity is correlated with a stress-induced continuous variation of lattice parameter accompanied by structural fluctuation. Neutron diffraction and electron microscopy observations reveal an unprecedented microstructure consisting of atomic-level entanglement of ordered and disordered crystal structures, which can be manipulated to tune the superelasticity. The discovery of the large elasticity related to the entangled structure paves the way for exploiting elastic strain engineering and development of related functional materials.
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| 3. |
- Yang, Bo, et al.
(author)
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Fair resource allocation using bargaining over OFDMA relay networks
- 2009
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In: Proceedings of the 48th IEEE Conference on Decision and Control, 2009 held jointly with the 2009 28th Chinese Control Conference. CDC/CCC. - : IEEE. - 9781424438716 ; , s. 585-590
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Conference paper (peer-reviewed)abstract
- This paper studies fair resource allocation schemes for orthogonal frequency-division multiple-access (OFDMA) with the decode-and-forward relaying strategy. To satisfy the heterogenous rate requirement of each user while considering the fairness and efficiency as performance indices, the bargaining theory is applied to allocate resource at a relay node to multiple source nodes. Motivated by the fact that each source's achievable rate on individual sub-carrier is limited by decodability constraint, we apply the Kalai-Smorodinsky bargaining (KSB) theory to allocate resource at the relay fairly. KSB ensures that all sources incur the same surplus rate penalty relative to the maximal surplus rate. To improve system efficiency, the Nash bargaining (NB) problem is formulated to maximize NB solution fairness criterion by exploiting multiuser diversity. A simple yet efficient algorithm is derived to assign sub-carrier and power at the relay for multiple users. Simulation results demonstrate that both KSB-based solution and NB solution can improve total rates while maintaining fairness among sources.
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| 4. |
- Shi, Y., et al.
(author)
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5G Applications of Intelligent Manufacturing Scenarios
- 2020
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In: Zhongguo Jixie Gongcheng/China Mechanical Engineering. - : China Mechanical Engineering Magazine Office. - 1004-132X. ; 31:2, s. 227-236
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Journal article (peer-reviewed)abstract
- To meet the current development requirements of Internet of Things in intelligent manufacturing field, 5G application technologies of corresponding manufacturing scenarios was studied herein. Firstly, different aspects of 5G key technologies were overviewed, including 5G-supported application scenarios, network slicing, NFV/SDN, multi-access edge computing, and D2D. After presenting an extended five-level architecture of CPS, multiple 5G applications in intelligent manufacturing scenarios were analyzed, including human-machine interfaces and production information technologies, process automation, factory automation, logistics and warehousing, equipment monitoring and maintenance. Furthermore, a 5G-based edge computing development framework was proposed to achieve the integration of the above-mentioned application scenarios. Finally, the challenges faced by 5G in intelligent manufacturing were discussed, which is helpful to the implementation of 5G-supported intelligent manufacturing.
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