Wyniki wyszukiwania - BazTech

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Synthesis and antibacterial properties of Fe3O4-Ag nanostructures

Pachla A., Lendzion-Bieluń Z., Moszyński D., Markowska-Szczupak A., Narkiewicz U., Wróbel R. J., Guskos N., Żołnierkiewicz G.

Polish Journal of Chemical Technology

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2016

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Vol. 18, nr 4

110--116

EN

Superparamagnetic iron oxide nanoparticles were obtained in the polyethylene glycol environment. An effect of precipitation and drying temperatures on the size of the prepared nanoparticles was observed. Superparamagnetic iron oxide Fe3O4 , around of 15 nm, was obtained at a precipitation temperature of 80°C and a drying temperature of 60°C. The presence of functional groups characteristic for a polyethylene glycol surfactant on the surface of nanoparticles was confirmed by FTIR and XPS measurements. Silver nanoparticles were introduced by the impregnation. Fe3O4-Ag nanostructure with bactericidal properties against Escherichia coli species was produced. Interesting magnetic properties of these materials may be helpful to separate the bactericidal agent from the solution.

2

Study of magnetic agglomerates in the nanomaterial system (Ti-Si-C(N))/C by the magnetic resonanse technique

Guskos N., Anagnostakis E. A., Żołnierkiewicz G., Typek J., Likodimos V., Guskos A., Biedunkiewicz A.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 5

18-21

EN

The nanomaterial system (Ti-Si-C(N)) has been prepared by a sol-gel method in flowing nitrogen atmosphere. In its magnetic response a very wide ESR line has been observed, arising from localized magnetic centers, along with an additional very broad and intense line in low magnetic field. The pertinent EPR/FMR parameters (resonance field, linewidth, integrated intensity) have been calculated and studied versus temperature. Analysis of the obtained temperature evolution of the EPR/FMR parameters has revealed characteristics of magnetic interactions between agglomerates and magnetic-dipole localized systems. Magnetic ordering processes for the localized magnetic centers are considered and discussed connected with traceable magnetic agglomerates being liable to enhance magnetic dipole-dipole interactions.

PL

Nanomateriał (Ti-Si-C(N)) został wytworzony metodą sol-żel w strumieniu gazowego azotu. Widmo ERP tego materiału składa się z bardzo wąskiej linii pochodzącej od zlokalizowanych centrów magnetycznych oraz z dodatkowego silnego i szerokiego sygnału znajdującego się w słabym polu magnetycznym. Obliczono standardowe parametry widma ERP/FMR (pole rezonansowe, szerokość linii, intensywność zintegrowana) oraz zbadano ich zależności temperaturowe. Analiza zmian temperaturowych tych parametrów pozwoliła określić charakterystyki oddziaływań magnetycznych pomiędzy aglomeratami i układem zlokalizowanych dipoli magnetycznych. Rozważono możliwość istnienia procesów uporządkowani magnetycznego w układzie zlokalizowanych centrów magnetycznych, które zostały wzmocnione przez system aglomeratów magnetycznych.

3

Effects of thermal treatment on magnetic properties of Ni2FeV3O11-.delta compound

Guskos N., Typek J., Żołnierkiewicz G., Błońska-Tabero A., Los S., Kempiński W.

Materials Science Poland

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2006

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Vol. 24, No. 4

983--990

EN

Ni2FeV3O11-.delat samples have been synthesized by the solid-state reaction method using two different heat treatment processes (samples of the type A and B). The XRD measurements have shown the same diffraction patterns for both types of samples. The temperature dependences of the electron paramagnetic resonance (EPR) spectra have been recorded for the two types of thermal annealing processes of Ni 2FeV3O11-.delta. Strong differences have been observed in the EPR spectra of both types of Ni2FeV3O 11-.delta. An intense EPR line has been recorded at high temperatures; it is suggested that the line is associated with oxygen-vanadium clusters (ferromagnetic ordering). The linewidth, resonance field and integrated intensity of the EPR spectra have shown a strong temperature dependence down to 200 K. Additionally, in one sample a very broad EPR line of Fe3+ ions appeared at low temperatures while at high temperatures this line was overlapped by the other line. The temperature dependence of the integrated intensity of this broad line has shown the Curie-Weiss behaviour. In the vanadate oxide materials with two strong magnetic ions in the structure (iron(III) and nickel(II)), the spectrum of the Fe3+ ions is not observed. Different oxygen deficiency processes could explain the differences in the EPR spectra of both types of Ni2FeV3O 11-.delta compounds.

4

Effect of calcination and structural additives on EPR spectra of nanocrystalline cobalt oxides

Guskos N., Typek J., Maryniak M., Żołnierkiewicz G., Podsiadły M., Arabczyk W., Lendzion-Bieluń Z., Narkiewicz U.

Materials Science Poland

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2006

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Vol. 24, No. 4

1095--1102

EN

Samples of nanocrystalline Co3O4 were prepared at various calcination temperatures and with various amounts of structural additives (CaO and Al2O3). The samples were characterized by X-ray diffraction. The average size and size distribution of nanoparticles have been calculated. Electron paramagnetic resonance (EPR) spectra of the samples were recorded at room temperature. The spectra have been attributed to divalent cobalt ions. Samples calcinated at higher temperatures showed an almost symmetrical, intensive EPR line. Temperature of calcination determined the character of the EPR spectra. The intensities of EPR spectra depended on the presence of CaO and Al2O3 additives