Dielectric Properties of Calcium Phosphate Ceramics

Calcium phosphate ceramics with various Ca/P ratios of 1, 2, 3, 4 and 8 were synthesized via sol-gel route. The effects of Ca/P molar ratio on structural, morphological, dielectric and antimicrobial properties were investigated in detail using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and dielectric measurements. The Ca/P molar ratio significantly affects the crystal structure and phase composition. The crystallite size, lattice parameters and volume of the unit cell were remarkably affected by the change in the Ca/P molar ratio. The microstructure is changed with increasing the Ca/P molar ratio. The relative permittivity and alternating current conductivity gradually decrease for the samples having the Ca/P ratios higher than 2. The dielectric loss decreases gradually with the increase of the molar ratio of Ca/P.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7222</p

Crystallinity Improvement of Co3O4 by Adding Thiourea

Tricobalt tetraoxide (Co3O4) samples having different thiourea/Co molar ratio of 0, 5 and 10 were prepared by wet chemical synthesis. The effects of thiourea content on the crystal structure-related parameters of Co3O4 were determined. The increase in the amount of thiourea caused a gradual decrease in the lattice parameters and specific surface area and an increase in the crystallinity and crystallite size. The experimental analysis results showed that thiourea content can be used to control the crystal structure-related parameters of Co3O4

Malva neglecta Wallr. (Ebegümeci)’nın In vitro Biyoaktif ve Fitokimyasal Özellikleri

M. neglecta çok yıllık otsu bir bitkidir ve Malvaceae familyasında yer almaktadır. Bu bitki ülkemizde her türlü toprakta kendiliğinden yetişir ve taze sürgünleri ile yaprakları sebze olarak tüketilir. Bu çalışmada M. neglecta toprak üstü kısımlarının su, etanol ve metanol ekstraktlarının antiradikal, antimikrobiyal, antikanser ve fitokimyasal içerikleri incelenmiştir. Elde edilen sonuçlara göre, M. neglecta toprak üstü kısımlarının yüksek antiradikal, antimikrobiyal, antikanser aktiviteye ve fitokimyasal içeriğe sahip olduğu anlaşılmıştır

Synthesis and Structural Characterization of Y-doped Pyramidal ZnO Powders

The present study focuses on the structural changes in ZnO powder induced by doping of a rare earth metal of Y. For this aim, we synthesized four ZnO samples with different Y-content using the combustion reaction method. X-ray powder diffraction (XRPD) technique and scanning electron microscopy (SEM) results confirm that the as-investigated structural parameters and morphology of the ZnO structure were affected directly by the concentration of Y dopant. For each Y-doped sample, randomly-oriented pyramidal morphology and the formation of a minority phase of Y2O3 were observed. A gradual increase in both lattice parameters and unit cell volume was detected with increasing Y content. All samples were found to be thermally stable in the temperature interval of 25-950 °C

Experimental and theoretical characterization of Dy-doped hydroxyapatites

The effects of adding Dy to the hydroxyapatite (HAp) structure were investigated experimentally and theoretically. The as-obtained experimental results with an increasing amount of Dy are as follows. X-ray diffraction, Raman, and Fourier transform infrared measurements verified the HAp structure for each specimen. The crystallinity, lattice parameters, lattice stress, strain, and anisotropic energy density were affected. Thermal stability and stoichiometry were not affected. It was observed that all the Dy-doped HAps have smaller crystallite size values compared to the un-doped HAp. The cell viability obtained from mouse fibroblast cell (L929) was higher than 82%, indicating all the samples were biocompatible. The theoretical findings, obtained from the density functional theory (DFT) calculations, exhibited a continuous decrease in the bandgap from 4.7109 to 3.7982 eV, an increase in the density from 3,155 to 3,189 kg m(-3), and an increase in the linear absorption coefficient.Management Unit of Scientific Research Projects of Firat University (FUBAP) [FF.22.28, FF.22.05]AcknowledgementsThis work was supported by the Management Unit of Scientific Research Projects of Firat University (FUBAP) (Project Numbers: FF.22.28 and FF.22.05)

Structural, spectroscopic, dielectric, and magnetic properties of Fe/Cu co-doped hydroxyapatites prepared by a wet-chemical method

In this study, the effects of Cu and Fe additives on the structural, dielectric, magnetic, thermal and morphology of hydroxyapatite (HAp) samples were investigated and reported in detail for the first time. The prepared systems were also modeled and examined theoretically. It can be said that both additives affect the thermal behavior of the HAp structure. The addition of Cu affected the morphology of submicron-sized particles with spherical-like shapes with a low degree of agglomeration. Diffuse reflection data revealed that the energy band gap values decreased as Cu was added to the Fe-based HAp structure. The dielectric constant (epsilon') had high values at low frequencies in all samples and decreased with increasing frequency. It could be concluded that Fe/Cu incorporation to hydroxyapatites enhanced its thermal, magnetic, and dielectric properties required for mimicking natural HAps to open a successful venue for medical application in the healing regeneration of bone.Deanship for Scientific Research of Imam Abdulrahman Bin Faisal University [2020-170-IRMC]The authors acknowledge the financial supports provided by the Deanship for Scientific Research of Imam Abdulrahman Bin Faisal University (Project application No. 2020-170-IRMC) . Also, the authors acknowledge the facilities used at Institute for Research and Medical consultations (IRMC) at Imam Abdulrahman Bin Faisal University.WOS:0007151334000012-s2.0-8511834109

Structural, optical, and electrical investigation of multilayered MnO2(n)/ NiO(p) heterojunctions for supercapacitors applications

Heterojunctions of alternating MnO2 and NiO thin films were deposited on an Indium Tin Oxide (ITO). The MnO2 and NiO thin films were synthesized by electrodeposition and sol-gel methods respectively. The structural morphology of the synthesized heterojunctions was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The microstructural and chemical compositions were examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman techniques. The optical properties were investigated by Ultraviolet-Visible (UV) analysis. The electrical conductivity, specific capacitance, and charge carrier density were determined using the Hall effect and Electrochemical impedance spectroscopy (EIS) methods. As a result, it was found that the MnO2 and NiO thin films crystallize in tetragonal and cubic crystal systems respectively. Increasing the number of NiO/MnO2 heterojunctions increases the electrical conductivity from 9.7 x 10- 7 to 1.2 x 10-3 S.cm- 1, the bandgap decreased 3.16 to 2.62 eV, the volume carrier density rises from 5.17 x 1011 to 4.62 x 1012 cm-3. The specimens constituted of two and four alternative staked MnO2 and NiO layers are characterized by a specific capacitance of 3.6 x 103 and 5.8 x 103 F.g -1 and capacitance retention of 14.8 and 12.9% which consider them promising materials for supercapacitor devices

The effects of Zn and Yb co-dopants on the electronic, radiation shielding, structural, thermal and spectroscopic properties of hydroxyapatite

This work presents a comprehensive investigation of the electronic properties of hydroxyapatite (HA) doped with zinc (Zn) and ytterbium (Yb). Four different compositions, namely 0.33Zn-0.33Yb-HA, 0.33Zn-0.66Yb-HA, 0.66Zn-0.33Yb-HA, and 0.66Zn-0.66Yb-HA, were studied using Density of States (DOS) and band structure calculations. The computed band gap values for each composition were determined to be 4.3097 eV, 4.1324 eV, 4.2527 eV, and 4.2088 eV, respectively. The observed decrease in the band gap energy from 0.33Zn-0.33Yb-HA to 0.66Zn-0.66Yb-HA signifies a significant impact of the dopant composition on the electronic properties of the material. Furthermore, the inclusion of ytterbium in the HA matrix resulted in the formation of a distinct band and peak in the density of states. This indicates the emergence of specific energy levels associated with Yb, suggesting a distinct influence on the electronic structure of the material. These findings provide valuable insights into the tunability of the electronic properties of HA through controlled doping with Zn and Yb. Such knowledge is crucial for tailoring materials with desired electronic characteristics, thus holding promise for various applications in electronic devices and biocompatible coatings. The as-modeled structures were synthesized via a wet chemical route. Fourier transform infrared (FTIR), Raman, and X-ray diffraction (XRD) analyses verified the formation of the HA structure for each sample. Differential thermal analysis (DTA) results showed that all the as-prepared samples were thermally stable. The negligible mass losses were detected for all the samples in the thermogravimetric analysis (TGA) measurements. The addition of both co-dopants affected crystal structure related parameters and decreased the crystallinity and cell viability