| 1. |
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 2. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Krasilnikov, A., et al.
(författare)
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Evidence of 9 Be + p nuclear reactions during 2ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
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Tidskriftsartikel (refereegranskat)abstract
- The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ω CH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.
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| 4. |
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| 5. |
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| 6. |
- 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. |
- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 29. |
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:9
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Tidskriftsartikel (refereegranskat)
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| 30. |
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Overview of the JET results
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10
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Tidskriftsartikel (refereegranskat)
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| 31. |
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| 32. |
- Litaudon, X., et al.
(författare)
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14 MeV calibration of JET neutron detectors-phase 1: Calibration and characterization of the neutron source
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
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Tidskriftsartikel (refereegranskat)abstract
- In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is 10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e.The neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4π sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within ± 5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in-vessel calibration and to derive the response of the JET neutron detectors to DT plasma neutrons starting from the response to the generator neutrons, and taking into account all the calibration circumstances.
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| 33. |
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| 34. |
- Hehlmann, Ruediger, et al.
(författare)
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The European LeukemiaNet : achievements and perspectives
- 2011
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 96:1, s. 156-162
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Tidskriftsartikel (refereegranskat)abstract
- The only way to cure leukemia is by cooperative research. To optimize research, the European Leukemia Net integrates 105 national leukemia trial groups and networks, 105 interdisciplinary partner groups and about 1,000 leukemia specialists from 175 institutions. They care for tens of thousands of leukemia patients in 33 countries across Europe. Their ultimate goal is to cure leukemia. Since its inception in 2002, the European Leukemia Net has steadily expanded and has unified leukemia research across Europe. The European Leukemia Net grew from two major roots: 1) the German Competence Network on Acute and Chronic Leukemias; and 2) the collaboration of European Investigators on Chronic Myeloid Leukemia. The European Leukemia Net has improved leukemia research and management across Europe. Its concept has led to funding by the European Commission as a network of excellence. Other sources (European Science Foundation; European Leukemia Net-Foundation) will take over when the support of the European Commission ends.
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| 38. |
- Bassan, Arianna, et al.
(författare)
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A Density Functional Study of a Biomimetic Non-Heme Iron Catalyst : Insights into Alkane Hydroxylation and Olefin Oxidation by a Formally HO-Fe(V)=O Oxidant
- 2004
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 11:2, s. 692-705
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Tidskriftsartikel (refereegranskat)abstract
- The reactivity of [HO(tpa)FeVO] (TPA=tris(2-pyridylmethyl)amine), derived from OO bond heterolysis of its [H2O(tpa)FeIIIOOH] precursor, was explored by means of hybrid density functional theory. The mechanism for alkane hydroxylation by the high-valent iron–oxo species invoked as an intermediate in Fe(tpa)/H2O2 catalysis was investigated. Hydroxylation of methane and propane by HOFeVO was studied by following the rebound mechanism associated with the heme center of cytochrome P450, and it is demonstrated that this species is capable of stereospecific alkane hydroxylation. The mechanism proposed for alkane hydroxylation by HOFeVO accounts for the experimentally observed incorporation of solvent water into the products. An investigation of the possible hydroxylation of acetonitrile (i.e., the solvent used in the experiments) shows that the activation energy for hydrogen-atom abstraction by HOFeVO is rather high and, in fact, rather similar to that of methane, despite the similarity of the HCH2CN bond strength to that of the secondary CH bond in propane. This result indicates that the kinetics of hydrogen-atom abstraction are strongly affected by the cyano group and rationalizes the lack of experimental evidence for solvent hydroxylation in competition with that of substrates such as cyclohexane.
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| 39. |
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| 40. |
- Bassan, Arianna, et al.
(författare)
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A Theoretical Study of the Cis-Dihydroxylation Mechanism in Naphthalene 1,2-dioxygenase
- 2004
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer Science and Business Media LLC. - 0949-8257 .- 1432-1327. ; 9:4, s. 439-452
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Tidskriftsartikel (refereegranskat)abstract
- The catalytic mechanism of naphthalene 1,2-dioxygenase has been investigated by means of hybrid density functional theory. This Rieske-type enzyme, which contains an active site hosting a mononuclear non-heme iron(II) complex, uses dioxygen and two electrons provided by NADH to carry out the cis-dihydroxylation of naphthalene. Since a (hydro)peroxo-iron(III) moiety has been proposed to be involved in the catalytic cycle, it was probed whether and how this species is capable of cis-dihydroxylation of the aromatic substrate. Different oxidation and protonation states of the Fe–O2 complex were studied on the basis of the crystal structure of the enzyme with oxygen bound side-on to iron. It was found that feasible reaction pathways require a protonated peroxo ligand, FeIII–OOH; the deprotonated species, the peroxo-iron(III) complex, was found to be inert toward naphthalene. Among the different chemical patterns which have been explored, the most accessible one involves an epoxide intermediate, which may subsequently evolve toward an arene cation, and finally to the cis-diol. The possibility that an iron(V)-oxo species is formed prior to substrate hydroxylation was also examined, but found to implicate a rather high energy barrier. In contrast, a reasonably low barrier might lead to a high-valent iron-oxo species [i.e. iron(IV)-oxo] if a second external electron is supplied to the mononuclear iron center before dioxygenation.
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| 41. |
- Bassan, A., et al.
(författare)
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Identifying isomers of C-78 by means of x-ray spectroscopy
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:16
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Tidskriftsartikel (refereegranskat)abstract
- X-ray photoelectron and absorption spectra of C-78 isomers have been generated using density functional theory with inclusion of the full core-hole potentials. Strong isomer dependence has been found in absorption, but not in the photoelectron spectra. C-78 isomers can be thought to be formed by inserting 18 carbon atoms into an opened C-60. We have shown how the different local arrangements of these 18 carbon atoms are responsible for the significant isomer dependence observed. Our calculated spectra are in excellent agreement with the experimental counterparts.
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| 42. |
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| 43. |
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| 44. |
- Bassan, Arianna, et al.
(författare)
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Oxygen Activation by Rieske Non-Heme Iron Oxygenases, a Theoretical Insight
- 2004
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:34, s. 13031-13041
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Tidskriftsartikel (refereegranskat)abstract
- The first steps of dioxygen activation in naphthalene 1,2-dioxygenase have been investigated by means of hybrid density functional theory. Reduction of molecular oxygen by this Rieske dioxygenase occurs in the catalytic domain accommodating a mononuclear non-heme iron(II) complex, and it requires two external electrons ultimately delivered by a Rieske [2Fe−2S] cluster hosted in the neighboring domain. Theoretical tools have been applied to gain insight into the O2-binding step and into the first one-electron-transfer process involving the mononuclear and the Rieske centers, and yielding an iron(II)−superoxo intermediate. The reaction, which is mimicked with a model including both metal sites, is found to be a reversible equilibrium. Although the entropic loss associated with the binding of O2 to iron(II) is not canceled by the corresponding enthalpic binding energy, it is, however, balanced by the exothermicity of the electron transfer process from the Rieske cluster to the dioxygen-bound iron(II) complex. The rationalization for the calculated energetics is related to the values of the ionization potential (IP) of the Rieske cluster and the electron affinity (EA) of the mononuclear iron complex: the latter is computed to be higher than the former, when dioxygen is bound to the metal. The possibility that a second external electron is delivered to the mononuclear site before dioxygenation of the substrate has also been examined. It is shown that, if the second electron is available in the Rieske domain, the electron transfer process is energetically favored. The results acquired with the large model comprising the two metal centers are compared to the corresponding information collected from the study of smaller models, where either the mononuclear iron complex or the Rieske cluster is included.
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| 45. |
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| 46. |
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| 47. |
- Bassan, Arianna, 1971-
(författare)
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Theoretical studies of mononuclear non-heme iron active sites
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The quantum chemical investigations presented in this thesis use hybrid density functional theory to shed light on the catalytic mechanisms of mononuclear non-heme iron oxygenases, accommodating a ferrous ion in their active sites. More specifically, the dioxygen activation process and the subsequent oxidative reactions in the following enzymes were studied: tetrahydrobiopterin-dependent hydroxylases, naphthalene 1,2-dioxygenase and α-ketoglutarate-dependent enzymes. In light of many experimental efforts devoted to the functional mimics of non-heme iron oxygenases, the reactivity of functional analogues was also examined.The computed energetics and the available experimental data served to assess the feasibility of the reaction mechanisms investigated. Dioxygen activation in tetrahydrobiopterin- and α-ketoglutarate-dependent enzymes were found to involve a high-valent iron-oxo species, which was then capable of substrate hydroxylation. In the case of naphthalene 1,2-dioxygenase, the reactivity of an iron(III)-hydroxperoxo species toward the substrate was investigated and compared to the biomimetic counterpart.
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| 48. |
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| 49. |
- Bassan, Paul, et al.
(författare)
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The inherent problem of transflection-mode infrared spectroscopic microscopy and the ramifications for biomedical single point and imaging applications.
- 2013
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Ingår i: The Analyst. - : Royal Society of Chemistry (RSC). - 1364-5528 .- 0003-2654. ; 138:1, s. 144-57
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Tidskriftsartikel (refereegranskat)abstract
- Transflection-mode FTIR spectroscopy has become a popular method of measuring spectra from biomedical and other samples due to the relative low cost of substrates compared to transmission windows, and a higher absorbance due to a double pass through the same sample approximately doubling the effective path length. In this publication we state an optical description of samples on multilayer low-e reflective substrates. Using this model we are able to explain in detail the so-called electric-field standing wave effect and rationalise the non-linear change in absorbance with sample thickness. The ramifications of this non-linear change, for imaging and classification systems, where a model is built from tissue sectioned at a particular thickness and compared with tissue of a different thickness are discussed. We show that spectra can be distorted such that classification fails leading to inaccurate tissue segmentation which may have subsequent implications for disease diagnostics applications.
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| 50. |
- Bein, T., et al.
(författare)
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Enhanced Lightweight Design - First Results of the FP7 Project ENLIGHT
- 2016
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Ingår i: Transportation Research Procedia. - : Elsevier B.V.. - 2352-1465. ; , s. 1031-1040
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Tidskriftsartikel (refereegranskat)abstract
- The European Green Vehicle project ENLIGHT aims to advance highly innovative lightweight material technologies for application in structural vehicle parts of future volume produced Electric Vehicles (EVs) along four axes: performance, manufacturability, cost effectiveness and lifecycle footprint. The main target is to develop viable and sustainable solutions for medium production volume up to 50.000 EVs destined to reach the market in the next 8-12 years. The specific objectives of the ENLIGHT project are on holistic and integrated conceptual design and manufacturing concerning how the technologies and materials addressed can be combined into a representative medium-volume EV. The solutions will be demonstrated in five modules: a front module and central floor module, a front door, a sub-frame and suspension system as well as a cross-car beam. In this paper, a summary of the major results obtained up to the 3rd project year will be presented. © 2016 The Authors.
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