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2453. Slow interatomic Coulombic decay of multiply excited neon clustersDenis Iablonskyi, Giovanni De Ninno, 2016, original scientific article Abstract: Ne clusters (∼ 5000 atoms) were resonantly excited (2 p→ 3 s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.
Keywords: Clusters, low-denisty matter, free-electron laser
Published in RUNG: 27.10.2020; Views: 2108; Downloads: 0
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2455. A Search for Ultra-high-energy Neutrinos from TXS 0506+056 Using the Pierre Auger ObservatoryA. Aab, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2020, original scientific article Keywords: ultra-high energy neutrinos, blazar TXS 0506+056, the Pierre Auger Observatory, high-energy astrophysics, neutrino astronomy, blazars, transient sources, active galaxies
Published in RUNG: 20.10.2020; Views: 3023; Downloads: 0
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2456. Temporal and spatial patterns of zinc and iron accumulation during barley (Hordeum vulgare L.) grain development. Journal of agricultural and food chemistry.Amelie Detterbeck, Paula Pongrac, Daniel Persson, Katarina Vogel-Mikuš, Mitja Kelemen, Primož Vaupetič, Primož Pelicon, Iztok Arčon, Søren Husted, Jan Kofod Shjoerring, Stephan Clemens, 2020, original scientific article Abstract: Breeding and engineering of biofortified crops will benefit from a better understanding of bottlenecks controlling
micronutrient loading within the seeds. However, few studies have addressed the changes in micronutrient concentrations,
localization, and speciation occurring over time. Therefore, we studied spatial patterns of zinc and iron accumulation during grain
development in two barley lines with contrasting grain zinc concentrations. Microparticle-induced-X-ray emission and laser ablationinductively
coupled plasma mass spectrometry were used to determine tissue-specific accumulation of zinc, iron, phosphorus, and
sulfur. Differences in zinc accumulation between the lines were most evident in the endosperm and aleurone. A gradual decrease in
zinc concentrations from the aleurone to the underlying endosperm was observed, while iron and phosphorus concentrations
decreased sharply. Iron co-localized with phosphorus in the aleurone, whereas zinc co-localized with sulfur in the sub-aleurone. We
hypothesize that differences in grain zinc are largely explained by the endosperm storage capacity. Engineering attempts should be
targeted accordingly.
Keywords: barley (Hordeum vulgare L.), biofortification, grain development, grain loading, LA-ICP-MS, μ-PIXE
Published in RUNG: 20.10.2020; Views: 2773; Downloads: 0
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2457. MAST, master modul in art, science and technology : podMAST - podcasts in Art, Science and TechnologyPeter Purg, Lange TeenaAbstract: podMAST is a series of open conversations among relevant voices from the crossings of Art, Science and Technology. Springing from an apparent need for (archiving and reflecting) in-depth knowledge about this timely crossover, it shall remain publicaly accessible to incite dialog with other interested practitioners and thinkers. Also it is to serve as study material for the newly developed international Master Module in Art, Science and Technology (MAST) of the project www.mastmodule.eu.
Keywords: Art, Science, Technology, discussion, conversation, podcast, practitioner, theory, practie, critical
Published in RUNG: 20.10.2020; Views: 2587; Downloads: 0
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2458. VELIKOKRAT NAS JE PRESENETILO, KAJ ATOMI DEJANSKO POČNEJO : IZTOK ARČONIztok Arčon, Nina Slaček, radio or television broadcast, podcast, interview, press conference Abstract: Razvoj novih materialov, nanotehnologije, molekularne biologije in še številnih drugih področij sodobnih znanosti je tesno povezan s podrobnim razumevanjem tega, kaj se dejansko dogaja na molekularnem oziroma atomskem nivoju. Za razvoj denimo novih nanostrukturnih materialov za baterije prihodnosti je nujno videti, kaj se v njih dejansko dogaja med samim delovanjem. To omogoča rentgenska absorpcijska spektroskopija s sinhrotronsko svetlobo.
»Ko z rentgenskim žarkom posvetimo na snov, iz atoma izbijemo elektron in ta odleti v okolico, se od nje odbija in nam na ta način sporoči, kaj se v njegovi okolici nahaja,« razlaga osnovni princip te metode prof. dr. Iztok Arčon.
Na ta način je mogoče pridobiti številne ključne podatke, ki pogosto na glavo postavijo predhodne domneve raziskovalcev. A za takšne raziskave je nujen sinhrotron. Tovrstnih pospeševalnikov ni veliko in merilni čas na sinhrotronu je potrebno pridobiti z vrhunsko zastavljenimi raziskavami. A tokratni gost Podob znanja, dr. Iztok Arčon, redni profesor na Univerzi v Novi Gorici, ima po zaslugi svojega znanstvenega dela na tem področju na široko odprta vrata, sodeluje pa raziskovalnimi skupinami z zelo različnih področij. Letos je za svoje dosežke prejel tudi Preglovo nagrado.
Foto: iz osebnega arhiva Iztoka Arčona
Keywords: rentgenska absorpcijska spektroskopija, sinhrotronsko sevanje, raziskave nanomaterialov, Preglova nagrada 2020
Published in RUNG: 19.10.2020; Views: 2722; Downloads: 0
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2460. X-ray absorption spectroscopy analysis: in situ, operando, in vivoIztok Arčon, 2020, published scientific conference contribution abstract (invited lecture) Abstract: X-ray absorption spectroscopy (XAS) is a powerful tool for characterisation of local structure and chemical state of selected elements in different new functional materials and biological or environmental samples. The XAS spectroscopy is based on extremely bright synchrotron radiation X-rays sources, which allow precise characterisation of bulk, nanostructured or highly diluted samples. With its two methods (XANES and EXAFS) it enables monitoring changes in valence states and local structures of constituent elements during chemical reactions under controlled reaction conditions, and it offers a possibility of a combination of X-ray spectroscopy and microscopy with sub-micron lateral resolution, crucial for analysis of biological samples on sub-cellular level. In this talk some typical examples of advanced XAS analysis will be presented.
Keywords: X-ray absorption spectroscopy, EXAFS, XANES, in-situ, operando
Published in RUNG: 17.10.2020; Views: 3107; Downloads: 0
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