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Effect of doping on structural and optical properties of ZnO nanoparticles: study of antibacterial properties

Maddahi P, Shahtahmasebi N, Kompany A., Mashreghi M, Safaee S, Roozban F

Materials Science Poland

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2014

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Vol. 32, No. 2

130—135

EN

Sol-gel method was successfully used for synthesis of ZnO nanoparticles doped with 10 % Mg or Cu. The structure, morphology and optical properties of the prepared nanoparticles were studied as a function of doping content. The synthesized ZnO:(Mg/Cu) samples were characterized using XRD, TEM, FTIR and UV-Vis spectroscopy techniques. The samples show hexagonal wurtzite structure, and the phase segregation takes place for Cu doping. Optical studies revealed that Mg doping increases the energy band gap while Cu incorporation results in decrease of the band gap. The antibacterial activities of the nanoparticles were tested against Escherichia coli (Gram negative bacteria) cultures. It was found that both pure and doped ZnO nanosuspensions show good antibacterial activity which increases with copper doping, and slightly decreases with adding Mg.

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Electrical properties comparison of NTC thermistors prepared from nanopowders and in mixed oxide process

Hosseini S. M., Ghanbari Shohany B., Azad N., Kompany A.

Materials Science Poland

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2011

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Vol. 29, No. 4

253--259

EN

We have synthesized and studied the effect of cobalt doping on the electrical properties of NTC thermistors with the composition of NiCoxMn2-xO4 (x = 0.0, 0.4, 0.8, 1.2, 1.6). The electrical properties of NTC thermistors prepared from nanopowders by gel auto-combustion and mixed oxides processes have been compared. The measurement results indicate that the fluctuations of B value in the samples made from nanopowders are smaller than that in the samples prepared using mixed oxides method. The electrical properties of these ceramics depend strongly on their grain size. The sintering time and temperature were chosen the same for the samples made from the powders prepared by the two methods. It was found that the samples made from nanopowders have smaller grain sizes.

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Effect of Y3+ and Nb5+ co-doping on dielectric and piezoelectric properties of PZT ceramicsn

Zak A. K., Jalalian A., Hosseini S. M., Kompany A., Shekofteh Narm T.

Materials Science Poland

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2010

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Vol. 28, No. 3

703--708

EN

The effect of co-doping of Pb1-xYx[(Zr0.53Ti0.47)1-xNbx]O3 bulk materials (0 ? x ? 0.03) with Y3+ ions and Nb5+ on their dielectric and piezoelectric properties o was investigated. Samples fabricated by conventional oxide mixing (OM) were sintered at 1250 °C for 2 h in a Pb-rich atmosphere. During the tetragonal-rhombohedral transition in the doped PZT ceramics a negligible effect was observed after additions of Y3+ and Nb5+ ions. The co-doping with both ions was noted to inhibit grain growth and promote densification and electrical properties. The optimal doping level was found to be at x = 0.015, for which the electric permittivity of 907, the piezoelectric constant of 323 pC/N, g33 of 40 mV/N, Qm of 272 and the electromechanical coupling factor (kp) of 0.49 were obtained.