| 1. |
- Vorobiev, Andrei, 1963, et al.
(författare)
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Tunable thin film bulk acoustic wave resonators with improved Q-factor
- 2010
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 96:21, s. Article Number: 212904 -
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Tidskriftsartikel (refereegranskat)abstract
- The tunable solidly mounted Ba0.25Sr0.75TiO3 (BSTO) thin film bulk acoustic wave resonators (TFBARs) with improved Q-factor are fabricated and characterized. The BSTO films are grown by magnetron sputtering at temperature 600 degrees C and extremely low sputter gas pressure 2 mTorr using on-axis configuration. The measured TFBARs Q-factor is more than 250 and mechanical Q-factor is more than 350 at 5 GHz resonance frequency. The improvement in the Q-factor is associated with reduction in the BSTO film grain misorientation. The latter is responsible for generation of shear waves leaking through the Bragg reflector and corresponding acoustic loss. (C) 2010 American Institute of Physics.
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| 2. |
- Aitaki, Georgia, 1986-
(författare)
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The Private Life of a Nation in Crisis : A Study on the Politics in/of Greek Television Fiction
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The private life of a nation in crisis offers in-depth studies of the fictional reconstruction and negotiation of moments of heightened societal tension that take place throughout the life of a nation. Its constituent papers focus on the role of television fiction in representing and shaping either critical moments, events, or periods that disrupt the normal pace of life, or unresolved societal tensions that become part of everyday life. What is more, the papers investigate the socio-cultural consequences of representations, in terms of the interpretative lenses television fiction provides for understanding the events as such. The empirical focus is placed on television fiction produced and broadcast in Greece, a country that has recently received a large share of publicity because of its protagonistic role in the late 2000s Eurozone crisis and, at the same time, a media landscape with multiple aspects that still remain uncharted. The thesis contains case studies from different periods of Greek television fiction, from 1989 – the year of the launch of the first private channels in Greece – onwards, in an attempt to connect the overall project to the production context characterizing commercial television, another aspect of European television in the process of continuous exploration. Through a close analysis of specific television programmes, as well as a complementary study of the production culture of private television in Greece, this thesis aspires to contribute to the general question regarding the role of the media in critical, uncertain, or tumultuous times, with an emphasis on television fiction’s potential to recode their meaning and to reflect back on society.
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| 3. |
- Aitaki, Georgia, 1986-
(författare)
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[TV review] Maestro/Maestro in Blue (MEGA TV/Netflix, 2022-)
- 2023
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Ingår i: Filmicon: Journal of Greek Film Studies. - 2241-6692. ; :8, s. 142-149
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Recension (populärvet., debatt m.m.)abstract
- Christopher (Christoforos) Papakaliatis is one of Greece’s most recognizable and successful “television authors” and Maestro in Blue, his latest creation, is the series that managed to turn Greece into a “Netflix nation”, both in the sense of a country being included in the global streaming service’s catalogue and in terms of a national television market being potentially “transformed by a foreign entrant affecting on many levels” (Lobato 2019: xi). On 19 December 2022, Maestro in Blue became the first Greek fiction show to launch on Netflix and the present review provides a critical reading of the series, based on an overview of its major strengths and weaknesses, as well as some additional reflections departing from the critical reception of the series, together with some concluding thoughts about the significance of small television nations being represented in the larger streaming universe.
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| 7. |
- Chapman, I.T., et al.
(författare)
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The Effect of Energetic Particles on Resistive Wall Mode Stability in MAST
- 2011
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 53, s. 065022-
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Tidskriftsartikel (refereegranskat)abstract
- Resistive wall mode (RWM) stability limits have been probed by MHD spectroscopy and numerical modelling. MAST plasmas have operated up to βN = 5.7, well above the predicted ideal kink no-wall limit or measured resonant field amplification limits due to a combination of rotation and kinetic damping. By varying the density, both the rotation and the fast ion distribution function have been changed dramatically. Detailed drift-kinetic modelling shows that whilst the contribution of energetic beam ions to RWM damping does increase at sufficiently high plasma rotation as to allow resonance with the fast ion precession frequency, the thermal ion damping always dominates over the fast ion contribution.
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| 8. |
- Chapman, I. T., et al.
(författare)
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The effect of plasma profile variation on the stability of the n=1 internal kink mode in rotating tokamak plasmas
- 2010
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 50:2, s. 025018-
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Tidskriftsartikel (refereegranskat)abstract
- The sensitivity of the stability of the ideal n = 1 internal kink mode to variations in the plasma profiles is analysed both analytically and numerically in rotating tokamak plasmas. These stability analyses have been carried out including the centrifugal effects of toroidal plasma rotation upon the equilibrium, and also inconsistently when the equilibrium is treated as static. The change in plasma stability due to rotation is partially (consistent equilibrium) or wholly (inconsistent treatment) determined by the radial profiles of the plasma density and rotation velocity. It is found that the internal kink mode stability is strongly influenced by small variations in these plasma profiles. The implications of this extreme sensitivity are discussed, with particular reference to experimental data from MAST.
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| 9. |
- Chapman, I. T., et al.
(författare)
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The effects of sheared toroidal rotation on stability limits in tokamak plasmas
- 2011
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 53:12, s. 125002-
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Tidskriftsartikel (refereegranskat)abstract
- Sheared toroidal rotation is found to increase the ideal external kink stability limit, thought to be the ultimate performance limit in fusion tokamaks. However, at rotation speeds approaching a significant fraction of the Alfven speed, the toroidal rotation shear drives a Kelvin-Helmholtz-like global plasma instability. Optimizing the rotation profile to maximize the pressure before encountering external kink modes, but simultaneously avoiding flow-driven instabilities, can lead to a window of stability that might be attractive for operating future high-performance fusion devices such as a spherical tokamak component test facility.
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| 10. |
- Chapman, I. T., et al.
(författare)
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The merits of ion cyclotron resonance heating schemes for sawtooth control in tokamak plasmas
- 2015
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Ingår i: Journal of Plasma Physics. - : Cambridge University Press. - 0022-3778 .- 1469-7807. ; 81:06
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Tidskriftsartikel (refereegranskat)abstract
- JET experiments have compared the efficacy of low-and high field side ion cyclotron resonance heating (ICRH) as an actuator to deliberately minimise the sawtooth period. It is found that low-field side ICRH with low minority concentration is optimal for saw tooth control for two main reasons. Firstly, low-field side heating means that any toroidal phasing of the ICRH (-90 degrees, +90 degrees or dipole) has a destabilising effect on the sawteeth, meaning that dipole phasing can be employed, since tins is preferable due to less plasma wall interaction from Resonant Frequency (RI) sheaths. Secondly, the resonance position of the low field side ICRH does not have to be very accurately placed to achieve saw tooth control, relaxing the requirement for real-time control of the RF frequency. These empirical observations have been confirmed by hybrid kinetic-magnetohydrodynamic modelling, and suggest that the ICRH antenna design for ITER is well positioned to provide a control actuator capable of having a significant effect on the sawtooth behaviour.
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