0000000000002833

AUTHOR

Imen Krad

showing 2 related works from this author

Dielectric relaxation phenomenon and conductivity in lead-free ceramics

2018

Abstract Relaxation phenomena and electric conductivity of (1-x) KNbO3-xK0.5Bi0.5TiO3 system where x = 0, 0.025, 0.05, 0.075, 0.1, 0.2, 0.3 have been studied at high temperature. A relaxation behavior was observed in temperature range 400 K ≤ T ≤ 550 K for orthorhombic solid solutions at room temperature. The activation energy (Ea) of this phenomenon was range from 0.68 eV for x = 0–0.489 eV for x = 0.075 with τ0 = 10−13 s. The relaxation was attributed to hopping of oxygen vacancies for solid solutions x ≤ 0.075. Substitution by K0.5Bi0.5TiO3 does not affect the electrical conductivity of KNbO3 too much, while the mobility of species such as oxygen vacancies and oxygen ions allow the incre…

Materials scienceCondensed matter physicschemistry.chemical_element02 engineering and technologyActivation energyDielectricConductivityAtmospheric temperature range010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesOxygen0104 chemical sciencesElectronic Optical and Magnetic MaterialschemistryElectrical resistivity and conductivityRelaxation (physics)Electrical and Electronic Engineering0210 nano-technologySolid solutionPhysica B: Condensed Matter
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Thermodynamic studies of iron(III) complex of some new dihydroxamic acids model of rhodotorulic acid

2018

Abstract The objective of this research is to elucidate the coordination chemistry and the structure of complexes formed with siderochelates organic ligands and the physico-chemical studies of iron(III) complexation. Three dihydroxamic acids synthesized ((LCyEt)2−, (LCyPr)2− and (LO)2−) mimicking a fungal siderophore, rhodotorulic acid. They were evaluated with iron(III) chelation by potentiometric and spectrophotometric titrations in 0.1 M KNO3. These measurements revealed the formation of dileptic and trileptic complexes in excess ligand conditions. The chemical model includes five species of [Fem(L)lHh](3m−2l+h)+ with general formula: [Fe(L)]+, [Fe(L)(OH)], [Fe(L)(OH)2]−, [Fe(L)2H] and […

chemistry.chemical_classificationAbsorption spectroscopy010405 organic chemistryChemistryLigandElectrospray ionizationPotentiometric titration010402 general chemistry01 natural sciencesMedicinal chemistry0104 chemical sciencesCoordination complexInorganic ChemistryRhodotorulic acidchemistry.chemical_compoundMaterials ChemistryTitrationChelationPhysical and Theoretical ChemistryInorganica Chimica Acta
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