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- 2019
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Tidskriftsartikel (refereegranskat)
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- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Guo, Peng Fei, et al.
(författare)
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Iron-chelated thermoresponsive polymer brushes on bismuth titanate nanosheets for metal affinity separation of phosphoproteins
- 2020
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 0927-7765. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- Separation of phosphoproteins plays an important role for identification of biomarkers in life science. In this work, bismuth titanate supported, iron-chelated thermoresponsive polymer brushes were prepared for selective separation of phosphoproteins. The iron-chelated thermoresponsive polymer brushes were synthesized by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and glycidyl methacrylate, followed by a ring opening reaction of epoxy group, and chelation of the obtained cis-diols with Fe3+ ions. The composite material was characterized to determine the size and thickness, the content of the organic polymer and the metal loading. The bismuth titanate supported, iron-chelated thermoresponsive polymer brushes showed selective binding for phosphoproteins in the presence of abundant interfering proteins, and a high binding capacity for phosphoproteins by virtue of the metal affinity between the metal ions on the polymer brushes and the phosphate groups in the phosphoproteins (664 mg β-Casein per g sorbent). The thermoresponsive property of the polymer brushes made it possible to adjust phosphoprotein binding by changing temperature. Finally, separation of phosphoproteins from a complex biological sample (i.e. milk) was demonstrated using the nanosheet-supported thermoresponsive polymer brushes.
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| 5. |
- Jiang, Wenyu, et al.
(författare)
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Resolving Quantum Interference Black Box through Attosecond Photoionization Spectroscopy
- 2023
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Ingår i: Physical Review Letters. - 0031-9007. ; 131:20
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Tidskriftsartikel (refereegranskat)abstract
- Multiphoton light-matter interactions invoke a so-called "black box"in which the experimental observations contain the quantum interference between multiple pathways. Here, we employ polarization-controlled attosecond photoelectron metrology with a partial wave manipulator to deduce the pathway interference within this quantum 'black box"for the two-photon ionization of neon atoms. The angle-dependent and attosecond time-resolved photoelectron spectra are measured across a broad energy range. Two-photon phase shifts for each partial wave are reconstructed through the comprehensive analysis of these photoelectron spectra. We resolve the quantum interference between the degenerate p→d→p and p→s→p two-photon ionization pathways, in agreement with our theoretical simulations. Our approach thus provides an attosecond time-resolved microscope to look inside the "black box"of pathway interference in ultrafast dynamics of atoms, molecules, and condensed matter.
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| 6. |
- Lin, Dongxu, et al.
(författare)
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Construction of an Iodine Diffusion Barrier Using Network Structure Silicone Resin for Stable Perovskite Solar Cells
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 13:7, s. 8138-8146
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Tidskriftsartikel (refereegranskat)abstract
- Long-term stability of organic-inorganic hybrid perovskite solar cells (PSCs) is inhibited by ion diffusion. Herein, we introduce a thermally stable and hydrophobic silicone resin layer with a network structure as an interfacial layer between the perovskite and the hole-transporting layer ( HTL). Experimental and theoretical investigations confirm that the small Si-O-Si unit in the network forms both Si-I and Pb-O bonds with the perovskite surface, which physically and chemically inhibit the diffusion and self-release of iodine. Besides, the silicone resin layer suppresses the thermal crystallization of spiro-OMeTAD and optimizes the interfacial energy level alignment for hole extraction. The power conversion efficiency (PCE) of a perovskite solar cell with a silicone resin layer is improved to 21.11%. The device maintains more than 90.1% of its original PCE after 1200 h under 85 degrees C thermal stress, 99.6% after 2000 h under RH similar to 55 +/- 5%, and 83% of its original PCE after light soaking in air for 1037 h.
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| 8. |
- Tian, Hongxiang, et al.
(författare)
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Evaluating EYM amplitudes in four dimensions by refined graphic expansion
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :4
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Tidskriftsartikel (refereegranskat)abstract
- The recursive expansion of tree level multitrace Einstein-Yang-Mills (EYM) amplitudes induces a refined graphic expansion, by which any tree-level EYM amplitude can be expressed as a summation over all possible refined graphs. Each graph contributes a unique coefficient as well as a proper combination of color-ordered Yang-Mills (YM) amplitudes. This expansion allows one to evaluate EYM amplitudes through YM amplitudes, the latter have much simpler structures in four dimensions than the former. In this paper, we classify the refined graphs for the expansion of EYM amplitudes into N k MHV sectors. Amplitudes in four dimensions, which involve k + 2 negative-helicity particles, at most get non-vanishing contribution from graphs in N k′ (k′ ≤ k) MHV sectors. By the help of this classification, we evaluate the non-vanishing amplitudes with two negative-helicity particles in four dimensions. We establish a correspondence between the refined graphs for single-trace amplitudes with (g−i,g−j) or (h−i,g−j) configuration and the spanning forests of the known Hodges determinant form. Inspired by this correspondence, we further propose a symmetric formula of double-trace amplitudes with (g−i,g−j) configuration. By analyzing the cancellation between refined graphs in four dimensions, we prove that any other tree amplitude with two negative-helicity particles has to vanish.
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