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Showing 2 results for jafari fesharaki
THE GREEN SYNTHESIS OF GOLD NANOPARTICLES USING THE ETHANOL EXTRACT OF BLACK TEA AND ITS TANNIN FREE FRACTION
M. Banoee,z. Ehsanfar, N. Mokhtari,m. R. Khoshayand, A. Akhavan Sepahi, P. Jafari Fesharaki,h. R. Monsef-Esfahani,, A. R. Shahverdi,
Volume 7, Issue 1 (winter 2010 2010)
Abstract

Abstracts:

nanoparticles. All the extracts were used separately for the synthesis of gold nanoparticles through the reduction of

aqueous AuCl

gold ions to gold nanoparticles. The ethanol extract of black tea and its tannin free ethanol extract produced gold

nanoparticles in the size ranges of 2.5-27.5 nm and 1.25-17.5 nm with an average size of 10 nm and 3 nm, respectively.

The prepared colloid gold nanoparticles, using the ethanol extract of black tea, did not show the appropriate stability

during storage time (24 hours) at 4

showed no particle aggregation during short and long storage times at the same conditions. To the best of our

knowledge, this is the first report on the rapid synthesis of gold nanoparticles using ethanol extract of black tea and

its tannin free fraction.

In this research the ethanol extract of black tea and its tannin free fraction used for green synthesis of gold4¯. Transmission electron microscopy and visible absorption spectroscopy confirmed the reduction ofoC. In contrast, gold colloids, which were synthesized by a tannin free fraction
Enhancing Dielectric and Ferroelectric Properties in PFN–PT Ceramics via (Ca,Sr)ZrO3 Modification for Advanced Electronic Applications
Marjaneh Jafari Fesharaki,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
The structural, dielectric, and ferroelectric properties of (1−x)PFN–PT/x(Ca,Sr)ZrO₃ ceramics (x = 0–0.08) were systematically investigated. X-ray diffraction analysis confirmed the formation of a single-phase perovskite structure, while Rietveld refinement revealed a gradual reduction in the monoclinic lattice distortion with increasing CZ and SZ contents, indicating structural evolution toward a pseudocubic-like state near the morphotropic phase boundary (MPB). Quantitative FE-SEM analysis showed dense microstructures with progressive grain refinement at higher modifier concentrations. Temperature-dependent dielectric measurements exhibited the highest dielectric constant for the x = 0.04 compositions, whereas the modified Curie–Weiss analysis confirmed diffuse phase transition and relaxor behavior, with γ values of 1.94 and 1.68 for PFN–PT:0.04CZ and PFN–PT:0.04SZ, respectively. Room-temperature ferroelectric measurements yielded maximum remanent polarization (Pr) values of 24.32 and 34.26 μC cm⁻² for the CZ- and SZ-modified ceramics at x = 0.04. The enhanced dielectric and ferroelectric properties are closely correlated with the reduced monoclinic distortion near the MPB, highlighting the crucial role of structural optimization in improving the functional performance of PFN–PT-based ceramics.
 
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