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Hybrid upconverting/paramagnetic Fe3O4/Gd2O3:Er3+, Yb3+, Mg2+, Nd3+ nanoparticles : synthesis, characterization and biological applications

Kamińska Izabela, Sobczak Kamil, Zhydachevskyy Yaroslav, Wojciechowski Tomasz, Minikayev Roman, Sikora-Dobrowolska Bożena, Lewińska Sabina, Chojnacki Michał, Fronc Krzysztof

Opto-Electronics Review

2024

Vol. 32, No. 2

art. no. e150182

The goals of this work are to design and develop a technology for fabrication and study of multifunctional properties of core/shell nanoparticles (NPs) as magnetic/luminescent markers. The new hybrid core/shell Fe₃O₄/Gd₂O₃:1% Er³+, 18% Yb³+, 2.5% Mg²+, x% Nd³+ NPs doped with different concentrations of neodymium ions, where x = 0%, 0.5%, 0.75%, 1%, 2%, 4%, were synthesized by the co-precipitation method. The NPs were characterised using XRD, TEM, SEM, EDX, confocal microscopy and photoluminescence. Fe₃O₄ (core) consists of several 13 nm NPs. The core/shell NPs have sizes from 220 nm to 641 nm. In this latter case, the shell thicknesses were 72, 80, and 121 nm. The upconversion efficiency properties and magnetic properties of the hybrid NPs were investigated. In the core/shell NPs, the addition of Nd³+ quenches the luminescence. The magnetic response of core/shell samples is rather paramagnetic and does not differ significantly from that registered for the shell material alone. For Gd₂O₃:1% Er³+, 18% Yb³+ and Fe₃O₄/Gd₂O₃:1% Er³+, 18% Yb³+, 2.5% Mg²+, 0.5% Nd³+, at 300 K, the values of the magnetization registered at ~ 40 kOe are similar and equal to ~ 5.3 emu·g⁻¹. The survivability of the HeLa tumor cells with the presence of the core/shell NPs was investigated for 24 h. The NPs are non-toxic up to a concentration of 1000 μg·ml⁻¹ and penetrate cells in the process of endocytosis which has been confirmed by confocal microscope studies.

Assessment of traffic noise levels in the city of Pila

Gorzelańczyk Piotr, Sobczak Kamil, Ližbetinová Lenka

Archiwum Motoryzacji

2023

Vol. 100, nr 2

75--84

The last few decades have been characterised by the rapid development of technology and various industries around the world, as well as increasing levels of urbanisation. The development of technology has resulted in the emergence of many inventions, vehicles and equipment. This has resulted in many unforeseen consequences generating threats to the environment in which humans’ function. One of these hazards is the noise emitted by vehicles. For this reason, environmental protection was created in response to threats to human existence (this work is to determine the level of noise resulting from traffic transportation in the city of Pila. In order to achieve the given objective in the city, sound values will be adopted and an acoustic map will be developed on their basis. A large amount of noise in the city of Pila is caused by road transportation, but from the results of the study it can be said that it is minimally exceeded only on two streets by less than five decibels and on three other streets where it is equal to the permissible noise value. The main places where the most noise is generated are two-lane roads and traffic lights and roundabouts. A lot of noise is generated when there are a large number of vehicles slowing down and starting in these places. A very big plus in the fight against noise in Pila is public transportation.

High temperature resistance of silicide-coated niobium

Szklarek Radosław, Tański Tomasz, Mendala Bogusław, Staszuk Marcin, Krzemiński Łukasz, Nuckowski Paweł, Sobczak Kamil

Bulletin of the Polish Academy of Sciences. Technical Sciences

2021

Vol. 69, nr 5

art. no. e137416

In this paper, thermal oxidation resistance of silicide-coated niobium substrates was tested in a temperature range of 1300–1450°C using an HVOF burner. Pure niobium specimens were coated using the pack cementation CVD method. Three different silicide thickness coatings were deposited. Thermal oxidation resistance of the coated niobium substrates was tested in a temperature range of 1300–1450°C using an HVOF burner. All samples that passed the test showed their ability to stabilize the temperature over a time of 30 s during the thermal test. The rise time of substrate temperature takes about 10 s, following which it keeps constant values. In order to assess the quality of the Nb-Si coatings before and after the thermal test, light microscopy, scanning electron microscopy (SEM) along with chemical analysis (EDS), X-ray diffraction XRD and Vickers hardness test investigation were performed. Results confirmed the presence of substrate Nb compounds as well as Si addition. The oxygen compounds are a result of high temperature intense oxidizing environment that causes the generation of SiO phase in the form of quartz and cristobalite during thermal testing. Except for one specimen, all substrate surfaces pass the high temperature oxidation test with no damages.