11. Silica-coated ▫$Bi2_Se_3$▫ topological insulator nanoparticles: preserving their optical properties and make them biocompatible : preserving their optical properties and make them biocompatibleBlaž Belec, Nina Kostevšek, Giulia Della Pelle, Sebastjan Nemec, Slavko Kralj, Martina Bergant Marušič, Sandra Gardonio, Mattia Fanetti, Matjaž Valant, 2023, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: topological insulator, bismuth selenide, photo-thermal material, biocompatibility, nanoparticles
Objavljeno v RUNG: 19.10.2023; Ogledov: 1651; Prenosov: 4
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12. A study of analysis method for the identification of UHECR source typeF. Yoshida, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: The autocorrelation analysis using the arrival direction of Ultra High Energy Cosmic Rays (UHECRs) has been previously reported by the Telescope Array (TA) experiment. It is expected that the autocorrelation function reflects the source distribution. We simulate the expected arrival direction distribution of the cosmic rays using the catalogs of candidate sources. We take into account random deflection in the magnetic fields, with the magnitude of deflection determined by the charge and energy of the cosmic rays, coherence length and magnitude of the extragalactic magnetic field (EGMF), and by distance to source. In addition, in order to compare with the results of TA experiment, we consider the TA exposure. We compare the autocorrelation of the arrival directions corresponding to different source catalogs with the isotropic distribution. We calculate the autocorrelation function for each type of source candidates using this procedure. We will discuss the ability of this method to identify the source type of UHECRs.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, energy spectrum, composition, anisotropy, autocorrelation, source models, magnetic fields
Objavljeno v RUNG: 04.10.2023; Ogledov: 1836; Prenosov: 10
 Celotno besedilo (2,71 MB)
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13. UHECR mass composition from anisotropy of their arrival directions with the Telescope Array SDM. Kuznetsov, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: We propose a new method for the estimation of ultra-high energy cosmic ray (UHECR) mass composition from a distribution of their arrival directions. The method employs a test statistic (TS) based on a characteristic deflection of UHECR events with respect to the distribution of luminous matter in the local Universe modeled with a flux-weighed 2MRS catalog. Making realistic simulations of the mock UHECR sets, we show that this TS is robust to the presence of galactic and non-extreme extra-galactic magnetic fields and sensitive to the mass composition of events in a set.
We apply the method to Telescope Array surface detector data for 11 years and derive new independent constraints on fraction of protons and iron in p-Fe mix at E>10 EeV. At 10100 EeV --- pure iron or even more massive composition. This result is in tension with Auger composition model inferred from spectrum-Xmax fit at 2.7σ (2.0σ) for PT'11 (JF'12) regular GMF model.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, composition, anisotropy, magnetic fields, 2MRS
Objavljeno v RUNG: 04.10.2023; Ogledov: 1982; Prenosov: 6
Celotno besedilo (3,02 MB)
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14. Effects of Galactic magnetic field on the UHECR anisotropy studiesR. Higuchi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: Telescope Array (TA) and Auger experiments reported anisotropies in the arrival direction of ultrahigh-energy cosmic rays (UHECRs). In particular, Auger Collaboration reported a correlation
between UHECR events and the flux model of assumed sources and suggested a contribution of
starburst galaxies (SBGs) to the anisotropy of UHECRs. However, in their study, the effect of
coherent deflections by the galactic magnetic field (GMF) is not taken into account. In this study, we investigated the effect of the GMF on the arrival directions of UHECRs using the cosmic ray propagation code CRPropa3. We used a backtracking technique which consists of propagating antiparticles to map the flux outside the galaxy to at the earth. We estimate the systematic effects caused by GMF in the reported likelihood analysis. We conduct likelihood analysis for mock UHECR datasets based on the flux pattern through the GMF model. We found systematic decrease of (f_ani, �) due to GMF. As prospects for the TAx4 experiment and joint analysis of Auger and TA collaborations, we develop the likelihood analysis method with the convolution of the rigidity spectrum.
Ključne besede: Telescope Array, TAx4, ultra-high energy, cosmic rays, anisotropy, galactic magnetic field, starburst galaxies
Objavljeno v RUNG: 29.09.2023; Ogledov: 1392; Prenosov: 6
Celotno besedilo (1,97 MB)
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16. Separation of mercuric ions using 2-thienylbenzimidazole/cucurbit[7] uril/iron-oxide nanoparticles by pH controlFalguni Chandra, Paltan Laha, Farah Benyettou, Tina Škorjanc, Naʹil Saleh, 2023, izvirni znanstveni članek Opis: 2-Thienylbenzimidazole (TBI)/cucurbit[7]uril (CB7) host–guest complex was used as a motif to significantly improve the turnover of γ-Fe3O4 magnetic nanoparticles for potential application in the separation of toxic mercuric ions in polluted water samples. The mechanism of restoring the original solid materials is based on applying the pH-controlled preferential binding of the CB7 host to the TBI guest. The analytical application of this concept has not been realized in the literature. The pH-controlled stimuli-responsive abilities were confirmed in aqueous solution by the three-order of magnitudes higher stability constant of the protonated TBIH+/CB7 complex (e.g., K = 4.8 × 108 M−1) when compared to neutral TBI/CB7 complex (e.g., K = 2.4 × 105 M−1), also manifested in an increase in pKa values by ~ 3.3 units in the ground state. The supramolecular interaction and adsorption on iron oxide nanoparticles (NPs) were also spectroscopically confirmed in the solid state. The excited-state lifetime values of TBI/CB7NPs increased upon lowering the pH values (e.g., from 0.6 to 1.3 ns) with a concomitant blue shift of ~ 25 nm because of polarity effects. The time-resolved photoluminescent behaviors of the final solids in the presence of CB7 ensured pH-driven reusable systems for capturing toxic mercuric ions. The study offers a unique approach for the controllable separation of mercury ions using an external magnet and in response to pH through preferential binding of the host to guest molecules on the top of magnetic surfaces.
Ključne besede: iron oxide nanoparticles (IONPs), mercury, thienylbenzimidazole, cucurbit[n]uril
Objavljeno v RUNG: 13.07.2023; Ogledov: 2442; Prenosov: 7
Celotno besedilo (2,41 MB)
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17. Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisationDarja Lisjak, Iztok Arčon, Matic Poberžnik, Gabriela Herrero‑Saboya, Ali Tufani, Andraž Mavrič, Matjaž Valant, Patricija Hribar Boštjančič, Alenka Mertelj, Darko Makovec, Layla Martin‑Samos, 2023, izvirni znanstveni članek Opis: Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1–4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe–phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.
Ključne besede: barium hexaferrite, Fe XANES, EXAFS, magnetic nanoparticles
Objavljeno v RUNG: 06.07.2023; Ogledov: 2445; Prenosov: 7
Celotno besedilo (3,60 MB)
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18. Multicomponent Cu-Mn-Fe silica supported catalysts to stimulate photo-Fenton-like water treatment under sunlightAndraž Šuligoj, Ivalina Trendafilova, Ksenija Maver, Albin Pintar, Alenka Ristić, Goran Dražić, Wael H. M. Abdelraheem, Zvonko Jagličić, Iztok Arčon, Nataša Zabukovec Logar, Dionysios D. Dionysiou, Nataša Novak Tušar, izvirni znanstveni članek Ključne besede: Magnetic catalyst, Photocatalyst, Water treatment, Sunlight, Contaminants of emerging concern, Photo-Fenton-like systems, Cu, Mn, Fe, XANES, EXAFS
Objavljeno v RUNG: 06.07.2023; Ogledov: 2508; Prenosov: 9
Celotno besedilo (4,32 MB) |
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20. Composites of transition metal dichalcogenides and topological insulators as catalytic materials for HERJelena Rmuš, Blaž Belec, Igor Milanović, Mattia Fanetti, Sandra Gardonio, Matjaž Valant, Sandra V. Kurko, 2023, izvirni znanstveni članek Ključne besede: MoS2/Bi2Se3 composites, electrocatalyst, hydrogen evolution reaction, electron transfer
Objavljeno v RUNG: 01.06.2023; Ogledov: 2400; Prenosov: 4
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