Iskanje po repozitoriju

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Opis: Temeljna namjera održavanja okruglog stola i objave ove knjige bila je da se pri obradi pravne zaštite zraka mora polaziti od struke koja je mjerodavna za pitanje očuvanja kvalitete zraka. Pravni pristup tom važnom području mora se na to nastaviti. Pritom se moraju poštivati temeljna pravila odgovarajuće struke, zahtjevi koje ona postavlja i prijedlozi kako poboljšati trenutačno stanje. Rasprava je pokazala da je zadovoljavajući učinak moguć jedino ako primjenjujemo takav pristup. Zadatak je pravnika pravno uobličiti ono što zahtijeva struka koja se bavi kvalitetom zraka. Takav je zahtjev postavljen i u raspravi.
Ključne besede: Pravna zaštita zraka, Okrugli stol, Hrvatska Akademija znanosti i umjetnosti, Zagreb, Republika Hrvatska
Objavljeno v RUNG: 14.06.2021; Ogledov: 2096; Prenosov: 0
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Opis: Topological insulators (TIs) represent a new state of matter that possess a different band structure than regular insulators or conductors. They are characterized with a band gap in the bulk and conductive topological states on the surface, which are spin polarized and robust toward contamination or deformation of the surface. Since the intriguing properties of the TIs are localized at the surface, it is important to obtain knowledge of the possible phenomena happening at the interface between TIs and other materials. This is especially true in the case of metals, due to the fact that such interfaces will be present in the majority of foreseen TI applications. The presented study combines microscopy and spectroscopy techniques for characterization of morphology, stability and chemical interaction at the interface between TI and metals deposited by means of physical vapor deposition. Our research is based on the interface of Bi2Se3 topological insulator with Ag, Ti and Pt – metals that can be encountered in devices or applications predicted to utilize the special properties of topological insulators. STM and SEM imaging of Ag/Bi2Se3 interface showed that Ag atoms arrange on the surface in the form of islands, whereas significantly bigger agglomerates are found at the surface steps. The interface was found to be unstable in time and resulted in the absorption of the metal into the crystal at room temperature. Evidences of a chemical reaction at the Ag/Bi2Se3 interface are presented, showing that new phases (Ag2Se, AgBiSe2 and metallic Bi) are formed. Deposition of Ti on Bi2Se3 resulted in different morphologies depending on the film thickness. At a very low coverage (<1 Å) islands are formed. However, the islands growth is hindered before the completion of a full layer due to the occurrence of a chemical reaction. No surface features could be detected by SEM for Ti coverage up to 20 nm. In contrary, when Ti thickness reached 40 nm, compressive stress triggered buckling of the deposited film. XPS analysis revealed that a redox solid-state reaction occurs at the Ti/Bi2Se3 interface at room temperature forming titanium selenides and metallic Bi. The reaction has significant kinetics even at cryogenic temperature of 130 K. Pt forms a homogenous film over the whole substrate surface, which is stable in time at room temperature. Although the interface of Pt with Bi2Se3 was found to be i less reactive compared to Ag and Ti, an interfacial phase formed upon annealing to ∼90 °C was detected by TEM cross section experiment. A model for prediction of interfacial reactions between a metal and Bi2Se3 based on the standard reduction potential of the metals and Gibbs free energy for a model reaction is presented. Based on these two values the reaction can be expected to result in the formation of binary and/or ternary selenides and Bi. Presented work shows on the importance of metal/topological insulator interfaces characterization taking into account the possibility of a chemical reaction with all of its consequences. Results should be considered for future theoretical and applicative studies involving such interfaces as well as for the possible engineering of 2D TI heterostructures.
Ključne besede: topological insulators, topological surface states, Bi2Se3, thin films, Ag, Ti, Pt, morphology, interfaces, solid-state reaction, metal selenides, reactivity, stability, electron microscopy, dissertations
Objavljeno v RUNG: 09.06.2021; Ogledov: 4041; Prenosov: 176
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Objavljeno v RUNG: 29.05.2021; Ogledov: 1829; Prenosov: 0
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Ključne besede: Atmospheric aerosol, Sahara dust, WRF-Chem, Northern Adriatic
Objavljeno v RUNG: 28.05.2021; Ogledov: 2075; Prenosov: 0
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Opis: The World Health Organization (WHO) identified air pollution as the world’s largest single environmental health risk causing seven million deaths per year, one in eight deaths globally. Of particular concern are heavily polluted and understudied urban centres: while thousands of scientific papers have been published on air quality of the cities such as London, UK and Los Angeles, USA, only 41 papers exist on the top 10 globally most polluted cities. Sarajevo, the capital of Bosnia and Herzegovina (B&H), is one of urban centres which often experiences low air quality due to the extensive use of non-renewable energy sources and geographical location. For example, in Sarajevo during 2010, an annual average concentration of particulate matter (PM) with a diameter smaller than 10 µm (PM10) was 50 µg/m3, a value 2.5x higer than the recommended WHO guidelines value of 20 µg/m3. Sarajevo Canton Winter Field Campaign 2017-2018 (SAFICA) took place in the Sarajevo Canton during the cold winter season of 2017 – 2018 (Dec 4, 2017 – Mar 15, 2018), the period historically characterized with the lowest air quality according to the available data. SAFICA project was lead by Federal hydrometeorological Institute of B&H, Institute of Public Health of the Sarajevo Canton, University of Sarajevo and University of Rijeka, and field measurements took place at three urban locations within the city of Sarajevo (Otoka, Pofalići i Bjelave) i one remote location (Ivan Sedlo mountain ridge). In this presentation, the basics of anthropogenic air pollution and its global influece on the air quality will be explained. Particular attention will be given to the atmospheric PM or aerosols, and aerosols formation mechanisms and the importance of their characteristics such as atmospheric concentration, size and chemical composition will be explained. Also, the reasons for the adverse effects of aerosols on human health and the correlation of atmospheric fine PM (PM2.5) concentrations and human mortality will be explained. Finally, preliminary results of SAFICA measurements campaign will be presented and compared with those from other global urban centers.
Ključne besede: atmospheric aerosol, Sarajevo, urban air pollution, SAFICA 2018
Objavljeno v RUNG: 26.05.2021; Ogledov: 2498; Prenosov: 0
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