| 11. |
- Belov, A., et al.
(författare)
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The integration and testing of the Mini-EUSO multi-level trigger system
- 2017
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177.
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Tidskriftsartikel (refereegranskat)abstract
- The Mini-EUSO telescope is designed by the JEM-EUSO Collaboration to observe the UV emission of the Earth from the vantage point of the International Space Station (ISS) in low Earth orbit. The main goal of the mission is to map the Earth in the UV, thus increasing the technological readiness level of future EUSO experiments and to lay the groundwork for the detection of Extreme Energy Cosmic Rays (EECRs) from space (Ebisuzaki et al., 2014). Due to its high time resolution of 2.5 μs, Mini-EUSO is capable of detecting a wide range of UV phenomena in the Earth’s atmosphere. In order to maximise the scientific return of the mission, it is necessary to implement a multi-level trigger logic for data selection over different timescales. This logic is key to the success of the mission and thus must be thoroughly tested and carefully integrated into the data processing system prior to the launch. This article introduces the motivation behind the trigger design and details the integration and testing of the logic.
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| 12. |
- Capel, Francesca, et al.
(författare)
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Mini-EUSO : A high resolution detector for the study of terrestrial and cosmic UV emission from the International Space Station
- 2017
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948.
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Tidskriftsartikel (refereegranskat)abstract
- The Mini-EUSO instrument is a UV telescope to be placed inside the International Space Station (ISS), looking down on the Earth from a nadir-facing window in the Russian Zvezda module. Mini-EUSO will map the earth in the UV range (300-400. nm) with a spatial resolution of 6.11. km and a temporal resolution of 2.5. μs, offering the opportunity to study a variety of atmospheric events such as transient luminous events (TLEs) and meteors, as well as searching for strange quark matter and bioluminescence. Furthermore, Mini-EUSO will be used to detect space debris to verify the possibility of using a EUSO-class telescope in combination with a high energy laser for space debris remediation. The high-resolution mapping of the UV emissions from Earth orbit allows Mini-EUSO to serve as a pathfinder for the study of Extreme Energy Cosmic Rays (EECRs) from space by the JEM-EUSO collaboration.
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| 13. |
- Fallqvist, Amie, et al.
(författare)
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Resolving the debated atomic structure of the metastable cubic SiNx tissue phase in nanocomposites with TiN
- 2018
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Ingår i: Physical Review Materials. - : American Physical Society. - 2475-9953. ; 2:9
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Tidskriftsartikel (refereegranskat)abstract
- The TiN/SiNx nanocomposite and nanolaminate systems are the archetype for super if not ultrahard materials. Yet, the nature of the SiNx tissue phase is debated. Here, we show by atomically resolved electron microscopy methods that SiNx is epitaxially stabilized in a NaCl structure on the adjacent TiN(001) surfaces. Additionally, electron energy loss spectroscopy, supported by first-principles density functional theory calculations infer that SiNx hosts Si vacancies.
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| 14. |
- Fausti, F., et al.
(författare)
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A multi-level triggering system for the Mini-EUSO UV telescope
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- As a pathfinder for the JEM-EUSO mission, Mini-EUSO is a 25cm diameter telescope which is going to be launched and positioned inside the International Space Station (ISS) in 2018. The main scientific goal of this mission is the achievement of a state-of-the-art UV map of the Earth from a 400 Km altitude, with ∼ 6 km of pixel spatial resolution, collecting data though a multi-level triggering system. The signal is collected with Multi-Anode Photo Multiplier Tubes (MAPMTs) and digitized by means of custom chips. The raw data moves then to a central system, the Zynq Board, where the trigger operates a data selection dividing different classes of events characterized by specific time scales. The acquired UV map will be used as discrimination threshold for the Extreme Energy Cosmic-Ray detection.
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| 15. |
- Khvan, A. V., et al.
(författare)
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Thermodynamic properties of tin: Part I Experimental investigation, ab-initio modelling of alpha-, beta-phase and a thermodynamic description for pure metal in solid and liquid state from 0 K
- 2019
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Ingår i: Calphad. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0364-5916 .- 1873-2984. ; 65, s. 50-72
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Tidskriftsartikel (refereegranskat)abstract
- Thermodynamic data for crystalline white and grey tin were assessed using an extended Einstein model from 0 K. Ab-initio simulations in the framework of density functional theory (DFT) with the quasiharmonic approximation (QHA) were carried out to define the heat capacities for both phases of tin from 0 K up to room temperatures. Good agreement was observed between theoretical and experimental heat capacities, which makes it possible to combine theoretical and experimental data to determine the standard entropies. Data for the liquid phase were described using a two state model. During the assessment, careful analysis of the experimental data was carried out. In order to fulfil the need for a precise evaluation of S-298(o) we needed to use an additional technique using multiple Einstein functions, which allows the experimental heat capacity and enthalpy data for the solid phase to be approximated accurately from 0 K up to the melting point and to estimate solid phase transition entropy and enthalpy which are difficult to measure due to a high activation barrier. Additional measurements of heat capacity were carried out where existing data were scarce.
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| 16. |
- Krasilnikov, O. M., et al.
(författare)
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Nonlinear elasticity of epsilon -Fe: The pressure effect
- 2019
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 99:18
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Tidskriftsartikel (refereegranskat)abstract
- Description of elasticity of iron at the ultrahigh pressures is a challenging task for physics, with a potential strong impact on other branches of science. In the present work, we calculate the elastic properties of hcp iron in the pressure range of 50-340 GPa beyond the linear elasticity approximation, conventionally assumed in theoretical studies. We define the higher order elastic constants and present expressions for the long-wave acoustic modes Gruneisen parameters of a compressed hcp crystal. We obtain the second and third order elastic constants of the hcp Fe in the considered pressure interval, as well as its Gruneisen parameters for the high-symmetry directions. The latter are directly compared with the Gruneisen parameters derived from the volume dependences of the vibrational frequencies calculated in the quasiharmonic approximation. The obtained results are used for the stability analysis of the hcp phase of iron at high pressures.
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| 17. |
- Krasnok, A. E., et al.
(författare)
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All-Dielectric Nanophotonics: Fundamentals, Fabrication, and Applications
- 2018
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Ingår i: World Scientific Series in Nanoscience and Nanotechnology. - : World Scientific. - 2301-301X .- 2335-6693. ; 16, s. 337-385
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter reviews a novel, rapidly developing field of modern light science named all-dielectric nanophotonics. This branch of nanophotonics is based on the properties of high-index dielectric nanoparticles which allow for controlling both magnetic and electric responses of a nanostructured matter. Here, we discuss optical properties of high-index dielectric nanoparticles, methods of their fabrication, and recent advances in practical applications, including the quantum source emission engineering, Fano resonances in all-dielectric nanoclusters, surface enhanced spectroscopy and sensing, coupled-resonator optical waveguides, metamaterials and metasurfaces, and nonlinear nanophotonics.
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| 18. |
- Leonov, I., et al.
(författare)
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Mott transition and magnetic collapse in iron-bearing compounds under high pressure
- 2017
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Ingår i: High Pressure Research. - : TAYLOR & FRANCIS LTD. - 0895-7959 .- 1477-2299. ; 37:2, s. 96-118
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the electronic, magnetic, and related structural transitions in the iron-based Mott insulators under high pressures relevant to the Earths lower mantle conditions. The paper focuses on the above-mentioned topics based primarily on our theoretical analysis and various experimental studies employing synchrotron X-ray diffraction, Fe-57 Mossbauer spectroscopy, and electrical transport measurements. We review the main theoretical tools employed for the analysis of the properties of materials with strongly interacting electrons and discuss the problems of theoretical description of such systems. In particular, we discuss a state-of-the-art method for calculating the electronic structure of strongly correlated materials, the DFT + DMFT method, which merges standard band-structure techniques (DFT) with dynamical mean-field theory of correlated electrons (DMFT). We employ this method to study the pressure-induced magnetic collapse in Mott insulators, such as wustite (FeO), magnesiowustite (Fe1-xMgx)O (x=0.25 and 0.75) and goethite (FeOOH), and explore the consequences of the magnetic collapse for the electronic structure and phase stability of these materials. We show that the paramagnetic cubic B1-structured FeO and (Fe,Mg)O and distorted orthorhombic (Pnma) FeOOH exhibit upon compression a high-to low-spin (HS-LS) transition, which is accompanied by a simultaneous collapse of local moments. However, the HS-LS transition is found to have different consequences for the electronic properties of these compounds. For FeO and (Fe0.75Mg0.25)O, the transition is found to be accompanied by a Mott insulator-to-metal phase transition. In contrast to that, both (Fe0.25Mg0.75)O and FeOOH remain insulating up to the highest studied pressures, indicating that a Mott insulator to band insulator phase transition takes place. Our combined theoretical and experimental studies indicate a crossover between localized to itinerant moment behavior to accompany magnetic collapse of Fe ions.
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| 19. |
- Li, S., et al.
(författare)
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Dielectric Yagi-Uda nanoantennas driven by electron-hole plasma photoexcitation
- 2017
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 917:6
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Konferensbidrag (refereegranskat)abstract
- All-dielectric nanophotonics based on high-index dielectric nanoparticles became a powerful platform for modern light science, providing many fascinating applications, including high-efficient nanoantennas and metamaterials. High-index dielectric nanostructures are of a special interest for nonlinear nanophotonics, where they demonstrate special types of optical nonlinearity, such as electron-hole plasma photoexcitation, which are not inherent to plasmonic nanostructures. Here, we propose a novel type of highly tunable all-dielectric Yagi-Uda nanoantennas, consisting of a chain of Si nanoparticles exciting by an electric dipole source, which allow tuning of their radiating properties via electron-hole plasma photoexcitation. We theoretically and numerically demonstrate the tuning of radiation power patterns and the Purcell effect by additional pumping of several boundary nanoparticles with relatively low peak intensities of fs-laser.
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| 20. |
- Milichko, V., et al.
(författare)
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Metal-Dielectric Nanocavity for Real-Time Tracing Molecular Events with Temperature Feedback
- 2018
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Ingår i: Laser and Photonics Reviews. - : Wiley. - 1863-8899 .- 1863-8880. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Plasmonic nanoparticles coupled with metallic films forming nanometer scale cavities have recently emerged as a powerful tool for enhancement of light-matter interaction. Despite high efficiency for sensing and light emission, such nanocavities exhibit harmful and uncontrolled optical heating which limits the ranges of light intensities and working temperature. In contrast to plasmonic nanoparticles, all-dielectric counterparts possess low Ohmic losses, high temperature stability along with a strong temperature-dependent Raman response. Here, we demonstrate that a silicon nanoparticle coupled with a thin gold film can serve as a multifunctional metal-dielectric (hybrid) nanocavity operating up to 1200 K. Resonant interaction of light with such nanocavity enables molecular sensing, heat-induced molecular events (protein unfolding), and their real-time tracing with a nanoscale thermometry through the monitoring enhanced Raman scattering both from the nanoparticle and analyzed molecules. We model numerically the thermo-optical properties of the hybrid nanocavity and reveal two alternative regimes of operation - with and without strong optical heating while other functionalities are preserved. We believe that the concept of the multifunctional hybrid nanocavities holds great potential for diverse photochemical and photophysical applications.
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