31. Element selective probe of the ultra-fast magnetic response to an element selective excitation in Fe-Ni compounds using a two-color FEL sourceEugenio Ferrari, C. Spezzani, Franck Fortuna, Renaud Delaunay, Franck Vidal, Ivaylo Nikolov, Paolo Cinquegrana, B. Diviacco, David Gauthier, G. Penco, Primož Rebernik Ribič, Giovanni De Ninno, 2017, original scientific article Keywords: free electron laser, two-color source, ultra-fast dynamics
Published in RUNG: 13.01.2020; Views: 3129; Downloads: 11
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32. Looking for a topological insulator in the tetradymite familyZipporah Rini Benher, Sandra Gardonio, Mattia Fanetti, Polina M. Sheverdyaeva, Paolo Moras, Matjaž Valant, 2019, published scientific conference contribution abstract Abstract: Materials that are topological insulators (TI) manifest a novel state for their electrons. They possess topological surface states that are not destroyed by the presence of non-magnetic impurities on their surfaces. This unique property lies in the bulk band structure and it is typically found in narrow gap semiconductor with strong spin-orbit coupling.
Bi2Se3 and Bi2Te3 belong to the class of compounds called tetradymites and are considered as the 3D-prototypical TI materials. However, these compounds are not usually insulators but have metallic bulk conductivity as a consequence of intrinsic defect doping: vacancies and anti-site defects. For these reasons, it is difficult to electrically gate these materials for the manipulation and control of charge carriers for realizing devices. This led to the search for other topological materials, which might have better insulating behavior in their bulk.
Theoretical studies have pointed out that ternary variants of the Bi2Se3 and Bi2Te3, such as Bi2Te2Se, Bi2Te2S, Bi2Se2S Sb2Te2Se and Sb2Te2S, should be stable TIs and potentially offer a chemical way to control TI behavior, in particular by lowering native doping. Among the cited ternary compounds, Bi2Se2S should manifest a genuine topological spin-transport regime hosting an isolated Dirac cone with the Dirac point in the gap as well. However, it has been poorly studied from the TI experimental perspective.
Therefore, to uncover the full potential of the predicted topological electronic properties of the Bi-Se-S system, in this presentation we will revisit the crystallographic and electronic structure of Bi2Se3-Bi2S3 solid solutions. The combined use of bulk and surface sensitive techniques such as X-ray diffraction (XRD), low energy electron diffraction (LEED), scanning electron microscopy (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray photoemission spectroscopy (XPS) was applied to analyze single crystal samples grown by us. The quality of the single crystals was suitable for rigorous measurement of the electronic properties by means of Angle Resolved Photoemission Spectroscopy. We unambiguously showed that within a certain solid solution range, the single crystals of Bi-Se-S have a rombohedral structure with the topological surface states as theoretically predicted.
Keywords: topological insulators, ternary tetradymite, electronic properties.
Published in RUNG: 19.12.2019; Views: 3910; Downloads: 0
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33. STUDY OF ELECTRONIC STATES OF THIN METAL FILMS ON HEAVY METAL SURFACES : MASTER'S THESISLuka Novinec, 2018, master's thesis Abstract: V magistrskem delu smo se osredoto£ili na pripravo in karakterizacijo
heterogenih ve£plastnih tankih filmov sestavljenih iz kovin ter teºkih kovin.
Za izdelavo vzorcev smo izbrali dve feromagnetni kovini, Fe in Gd, ter
eno divalentno kovino iz redkih zemelj, Yb. Tanke filme smo nana²ali na
kristalno povr²ino volframa W(110) ter molibdena Mo(110). V primeru Fe
na povr²ini W(110) in Mo(110) ter Yb na pov²ini Mo(110) smo uspe²no
dolo£ili pogoje, potrebne za nana²anje atomsko enakomernih filmov. S pomo
£jo kotno odvisne fotoemisije smo preu£evali kvantna stanja v Fe in Yb
filmih na Mo in W kristalih. Celotno eksperimentalno delo je potekalo na
ºarkovnih linijah VUV-Photoemission in²tituta (ISM-CNR) ter BaDElPh
pri sinhrotronu Elettra v Trstu.
Keywords: electronic states, thin metal films, heavy metal surfaces
Published in RUNG: 04.12.2019; Views: 4050; Downloads: 105
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34. A cellular network database for fingerprint positioning systemsDonatella Gubiani, Paolo Gallo, Andrea Viel, Andrea Dalla Torre, Angelo Montanari, 2019, published scientific conference contribution Abstract: Besides being a fundamental infrastructure for communication, cellular networks are increasingly exploited for positioning via signal fingerprinting.
Here, we focus on cellular signal fingerprinting, where an accurate and comprehensive knowledge of the network is fundamental.
We propose an original multilevel database for cellular networks, which can be automatically updated with new fingerprint measurements and makes it possible to execute a number of meaningful analyses. In particular, it allows one to monitor the distribution of cellular networks over countries, to determine the density of cells in different areas, and to detect inconsistencies in fingerprint observations.
Keywords: Cellular network, Signal fingerprinting, Multilevel database, Data analysis
Published in RUNG: 17.09.2019; Views: 3400; Downloads: 0
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35. Fibroblast involvement in soft connective tissue calcificationIvonne Pasquali Ronchetti, Federica Boraldi, Giulia Annovi, Paolo Cianciulli, Daniela Quaglino, 2013, review article Abstract: Soft connective tissue calcification is not a passive process, but the consequence of metabolic changes of local mesenchymal cells that, depending on both genetic and environmental factors, alter the balance between pro- and anti-calcifying pathways. While the role of smooth muscle cells and pericytes in ectopic calcifications has been widely investigated, the involvement of fibroblasts is still elusive. Fibroblasts isolated from the dermis of pseudoxanthoma elasticum (PXE) patients and of patients exhibiting PXE-like clinical and histopathological findings offer an attractive model to investigate the mechanisms leading to the precipitation of mineral deposits within elastic fibers and to explore the influence of the genetic background and of the extracellular environment on fibroblast-associated calcifications, thus improving the knowledge on the role of mesenchymal cells on pathologic mineralization.
Keywords: fibroblasts, PXE, PXE-likedisorders, elastin, extracellularmatrix, ectopiccalcification, mesenchymal
stromalcells
Published in RUNG: 23.08.2019; Views: 3167; Downloads: 0
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36. Ectopic calcification in β-thalassemia patients is associated with increased oxidative stress and lower MGP carboxylationFederica Boraldi, Maria Immaculada Garcia Fernandez, Chiara Paolinelli DeVincenzi, Giulia Annovi, Leon J. Schurgers, Cees Vermeer, Paolo Cianciulli, Ivonne Pasquali Ronchetti, Daniela Quaglino, 2013, original scientific article Keywords: Elastin
Oxidative stress
Matrix Gla protein
Ectopic calcification
Beta-thalassemia
Published in RUNG: 23.08.2019; Views: 3214; Downloads: 0
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37. Multi-wavelength aerosol absorption coefficient measurements: instrument inter-comparison and results of source and source-component modellingVera Bernardoni, Luca Ferrero, Francesca Soldan, Sara Valentin, Mario Massabò, Griša Močnik, Asta Gregorič, Marco Cataldi A., Ezio Bolzacchini, Paolo Prati, Gianluigi Valli, Roberta Vecchi, 2019, published scientific conference contribution abstract Keywords: aerosol absorption, method intercomparison
Published in RUNG: 17.07.2019; Views: 3498; Downloads: 0
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38. A map-matching algorithm dealing with sparse cellular fingerprint observationsAndrea Dalla Torre, Paolo Gallo, Donatella Gubiani, Chris Marshall, Angelo Montanari, Federico Pittino, Andrea Viel, 2019, original scientific article Abstract: The widespread availability of mobile communication makes mobile devices a resource for the collection of data about mobile infrastructures and user mobility. In these contexts, the problem of reconstructing the most likely trajectory of a device on the road network on the basis of the sequence of observed locations (map-matching problem) turns out to be particularly relevant. Different contributions have demonstrated that the reconstruction of the trajectory of a device with good accuracy is technically feasible even when only a sparse set of GNSS positions is available. In this paper, we face the problem of coping with sparse sequences of cellular fingerprints. Compared to GNSS positions, cellular fingerprints provide coarser spatial information, but they work even when a device is missing GNSS positions or is operating in an energy saving mode. We devise a new map-matching algorithm, that exploits the well-known Hidden Markov Model and Random Forests to successfully deal with noisy and sparse cellular observations. The performance of the proposed solution has been tested over a medium-sized Italian city urban environment by varying both the sampling of the observations and the density of the fingerprint map as well as by including some GPS positions into the sequence of fingerprint observations.
Keywords: Map-matching algorithm, trajectory, cellular fingerprint, Hidden Markov Model
Published in RUNG: 11.06.2019; Views: 3382; Downloads: 97
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39. Ultra-Fast-VUV Photoemission Study of UV Excited 2-NitrophenolA. Ciavardini, Marcello Coreno, Carlo Callegari, C. Spezzani, Giovanni De Ninno, Barbara Ressel, Cesare Grazioli, Monica de Simone, Antti Kivimak̈i, Paolo Miotti, Fabio Frassetto, Luca Poletto, Petra Rudolf, Simona Fornarini, Marco Pezzella, Enrico Bodo, Susanna Piccirillo, 2019, original scientific article Abstract: The initial deactivation pathways of gaseous 2-nitrophenol excited at 268 nm were investigated by time-resolved photoelectron spectroscopy (TRPES) with femtosecond-VUV light, produced by a monochromatized high harmonic generation source. TRPES allowed us to obtain new, valuable experimental information about the ultrafast excited-state dynamics of 2-nitrophenol in the gas phase. In accord with recent ab initio on-the-fly nonadiabatic molecular dynamic simulations, our results validate the occurrence of an ultrafast intersystem crossing leading to an intermediate state that decays on a subpicosecond time scale with a branched mechanisms. Two decay pathways are experimentally observed. One probably involves proton transfer, leading to the most stable triplet aci-form of 2-nitrophenol; the second pathway may involve OH rotation. We propose that following intersystem crossing, an ultrafast fragmentation channel leading to OH or HONO loss could also be operative.
Keywords: Ultrafast photoemission, nitrophenol
Published in RUNG: 12.02.2019; Views: 3658; Downloads: 0
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40. Map matching with sparse cellular fingerprint observationsAndrea Viel, Donatella Gubiani, Paolo Gallo, Angelo Montanari, Andrea Dalla Torre, Federico Pittino, Chris Marshall, 2018, published scientific conference contribution Keywords: map matching, fingerprint, trajectories
Published in RUNG: 09.12.2018; Views: 3692; Downloads: 0
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