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299 results on '"Kylián, Ondřej"'

29. Challenges in the deposition of plasma polymer nanoparticles using gas aggregation source: Rebounding upon impact and how to land them on a substrate.

Author

Solař, Pavel, Škorvánková, Kateřina, Kuzminova, Anna, and Kylián, Ondřej

Subjects
PLASMA deposition, METAL nanoparticles, NANOPARTICLES, POLYMERS, METALLIC oxides
Abstract

Plasma polymer nanoparticles (pp‐NPs) are relatively easy to produce by plasma‐based gas aggregation sources. However, as experimentally evidenced in this study for the case of C:H:N:O pp‐NPs, pp‐NPs are unlike metal/metal oxide nanoparticles prone to reflection from the substrate if they hit it with too high a speed. This may result in little or no deposition rate even though the nanoparticle beam is very intense. As is shown, the deposition of pp‐NPs can be promoted either by the adjustment of their speed before they reach the substrate or by a proper selection of a substrate. Concerning the latter, enhanced capturing of pp‐NPs was observed on structured or liquid substrates. [ABSTRACT FROM AUTHOR]

Published
2023
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34. Direct treatment of pepper (Capsicum annuum L.) and melon (Cucumis melo) seeds by amplitude-modulated dielectric barrier discharge in air.

Author

Homola, Tomáš, Prukner, Václav, Artemenko, Anna, Hanuš, Jan, Kylián, Ondřej, and Šimek, Milan

Subjects
CAPSICUM annuum, MUSKMELON, SEEDS, PEPPERS, MELONS, X-ray photoelectron spectroscopy
Abstract

This study evaluates low-temperature plasma generated by an amplitude-modulated dielectric barrier discharge (DBD) as a direct surface treatment of pepper and melon plant seeds. An analysis of the discharge and its products revealed the influence of the seeds inserted into the plasma on the total plasma power and concentration of O3 and NOx, which are the dominant reactive oxygen and nitrogen species produced by the plasma. The plasma treatment of the seeds led to higher viability and higher imbibition rate during the first hour of exposure to the wet environment. X-ray photoelectron spectroscopy (XPS) analysis confirmed changes in the O:C ratio for plasma-treated pepper and melon seeds. However, prolonged plasma treatment for 300 s affected pepper and melon seeds differently. While the O:C ratio gradually increased with plasma treatment time for pepper seeds, that for melon seeds decreased considerably for longer treatment times. Furthermore, detailed XPS analysis of pepper seeds revealed a profound increase in magnesium and calcium, which are often present in seed macronutrients, and a minor increase in potassium, silicon, sulfur, and phosphorus, which are present in micronutrients. These observations can be related to the possible redistribution of the elements owing to the plasma treatment, and thus the treatment might have an essential influence on the seed bulk. The findings presented in this study help elucidate the plasma interaction with surfaces of pepper and melon seeds and confirm the feasibility of the direct plasma treatment using power-modulated DBDs for applications in agriculture. [ABSTRACT FROM AUTHOR]

Published
2021
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46. Nanostructured Semi-Transparent TiO 2 Nanoparticle Coatings Produced by Magnetron-Based Gas Aggregation Source.

Author

Hanková, Adéla, Kuzminova, Anna, and Kylián, Ondřej

Subjects
NANOPARTICLES, TITANIUM dioxide, SURFACE coatings, BAND gaps, OPTICAL coatings
Abstract

A novel strategy to produce semi-transparent TiO2 nanoparticle-based coatings is investigated. This two-step strategy utilizes a magnetron-based gas aggregation source of Ti nanoparticles that are subsequently annealed in air at the temperature of 450 °C. It is shown that by using this technique, it is possible to fabricate highly porous and patterned TiO2 nanoparticle coatings with an optical band gap of around 3.0 eV on the substrate materials commonly used as transparent electrodes in photovoltaic applications or for water-splitting. In addition, it is shown that the morphology of the resulting coatings may be varied by changing the angle between the direction of the substrate and the incoming beam of nanoparticles. As demonstrated, the tilting of the substrate leads to the formation of columnar nanoparticle films. [ABSTRACT FROM AUTHOR]

Published
2023
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50. Calorimetric investigations in a gas aggregation source.

Author

Gauter, Sven, Haase, Fabian, Solař, Pavel, Kylián, Ondřej, Kúš, Peter, Choukourov, Andrei, Biederman, Hynek, and Kersten, Holger

Subjects
FLUX (Energy), THERMAL probe surveys, MAGNETRON sputtering, ENERGY conversion, ARGON
Abstract

A gas aggregation source based on DC magnetron sputtering was investigated using a passive thermal probe and supplementary diagnostics (Langmuir probe and quartz crystal microbalance). Parameter variations of pressure, axial distance, and magnetron current have been performed for three different targets (pure Cu, pure W, composite Cu/W) in argon discharge. The measurements showed the energy flux to be significantly higher for the case of the pure tungsten and the composite target compared to the copper target, which is likely a result of the strongly increased amount of neutrals being reflected from the heavier targets. Furthermore, gas rarefaction by the sputtered atoms was found to be essential for the understanding of the observed energy flux and that the dominant contributors to the energy flux in the higher pressure regime are comparable to those observed in the conventional lower pressure regime. Selected deposited films have been investigated ex-situ by scanning electron microscopy, which allowed us to gain insight into the nanoparticle formation in relation to the observed energy conversion. [ABSTRACT FROM AUTHOR]

Published
2018
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