Structural,optical and electronic characteristics of Cu and Mg-doped nano MnS sample prepared by molten salt solid state reaction

Journal of Materials Science: Materials in Electronics - Nano Mn0.95M0.05S (M ≡ Cu, Mg) samples were produced using molten salt solid state reaction method. Rietveld analysis of X-ray...     

Photophysical Parameters of Functional Transparent Polymethyl-Methacrylate/Double-Walled Carbon Nanotubes Nanocomposite Sheet Under UV-Irradiation

Polymethyl-methacrylate (PMMA)/double-walled carbon nanotubes DWCNTs was prepared by using casting technique and studying with different spectroscopic techniques. UV/Vis spectral analysis shows that, the transmittance reaches to 92 % for blank PMMA and decreases to 87 % for PMMA doped with 0.01 DWCNTs composite. The calculated refractive index and absorption coefficient increase, while the estimated values of Urbach energy decreased after embedding CNT into PMMA matrix. The optical band gap values were observed to vary slightly with doping amount. Photoluminescence (PL) spectra show that there is no shift in the emission peak position upon doping with CNTs, but PL intensity is enhanced.     

Technetium-99m-MIBI myocardial SPECT: supine versus right lateral imaging and comparison with coronary arteriography

Myocardial perfusion SPECT using the prone position improves inferior wall counts and decreases motion problems as compared with the usual supine position. Nonetheless, it is not suitable for women. In addition, it is associated with artifactual anteroseptal defects and hot spots. METHODS: The right lateral (RL) position was evaluated instead of the prone position in 72 patients (26 women). RL imaging was performed immediately after the supine imaging during a routine 2-day 99mTc-sestamibi exercise protocol. The SPECT images were scored semiquantitatively by three physicians. Moreover, regional myocardial counts, as well as extent and severity of defects, were assessed by quantitative polar map analysis. RESULTS: All patients tolerated the RL position well and there was no significant patient movement in either position. Higher inferior myocardial counts per pixel were observed in the RL than in supine images. Inferior wall defects (especially mild ones) were more common in the supine than the RL images, whereas defects in other regions were not different. Quantitative analysis confirmed these findings. Analysis of 34 patients with recent coronary arteriography revealed an overall coronary artery disease (CAD) supine- and RL-imaging specificity of 50% and 75%, respectively, and the sensitivities of both were 93%. Right CAD sensitivity, specificity and normalcy rates for the supine position were 100%, 44% and 55%, whereas those of the RL position were 94%, 75% and 90%, respectively. CONCLUSION: The RL position improves CAD diagnostic accuracy, particularly right CAD, without significant artifacts in other myocardial regions. Unlike the prone position, the RL position is well tolerated by both women and men.     

Structural,magnetic, and optical properties of nano-sized Ni0.85Se

Nanocrystalline Ni_0.85Se was synthesized by a hydrothermal method. X-ray diffraction analysis by Rietveld method indicated that Ni_0.85Se has a NiAs-type hexagonal structure. Narrow crystallite size distribution with an average area-weighted size of 〈ɛ_F〉 = 8.5 nm is obtained by Warren-Averbach method. Structural analysis revealed deformed Se atoms octahedron with the shortest distance between Se atoms in adjacent planes 〈Se–Se〉_adj smaller than between nearest neighbors in layer plane 〈Se–Se〉_nea, and a rather short interatomic distance between the transition metal atoms 〈Ni–Ni〉. The optical property of Ni_0.85Se was studied by UV-spectroscopy. Magnetic measurement shows a ferromagnetic phase transition for Ni_0.85Se below 14 K.     

The investigation of structural and magnetic properties of Er2−xCoxO3 nano-oxides

Journal of Materials Science: Materials in Electronics - The sol–gel technique was used to synthesize Er2?xCoxO3 (0.0?≤?x?≤?0.30) mixed oxides to...     

Influence of Cr and Fe doping on the structure,magnetic and optical properties of nano CuCo2O4

Nano CuCo_2-xM_xO₄ (x = 0, 0.1, 0.2, M = Cr or Fe) samples were synthesized by hydrothermal method. Synchrotron x-ray diffraction data obtained for the samples were subjected to phase analysis and manifested a single-phase cubic spinel structure for Cr-doped samples, while for Fe-doped samples two phases were identified. Cation distribution and cell parameter (a) were obtained from Rietveld X-ray diffraction analysis. FTIR analysis affirmed the formation of the cubic spinel and the cation distribution obtained. The nano nature of the samples and the particle morphology were examined by high-resolution transmission electron microscope (HRTEM) with selected area electron diffraction (SAED). UV-diffuse reflectance revealed that all samples have two optical energy gaps. For all Fe doped samples, the optical band gaps decreased, while for Cr-content x = 0.1 the bandgaps increased then reduced for x = 0.2. Doped samples exhibited a blue or red shift depending on the kind and amount of the dopant ions. The PL intensity and the emitted colors depended on the kind and amount of the dopant ions. Magnetic measurements disclosed the paramagnetic nature of CuCo₂O₄, while a weak ferromagnetic is revealed for CuCo_2-xCr_xO₄ and a ferromagnetic nature for CuCo_2-xFe_xO₄. Lowering the bandgap upon doping could make better mobility of lattice oxygen and enhancing the catalyst reducibility. Thus, the Cr and Fe-doped samples are expected to have better catalytic activity than the pristine one.     

Effect of Annealing Temperature on Structural and Magnetic Properties of Zn0.94Co0.05Cu0.01O

The doped ZnO system Zn_0.94Co_0.05Cu_0.01O (ZCCO) was prepared as a nano-polycrystalline by a simple sol–gel process, then air annealed at different temperatures. Applying X-ray diffraction (XRD) and the Rietveld method, structural analysis showed that Co and Cu replace Zn substitutionally yielding ZCCO single phase. The refined u-fractional coordinate of Zn increases monotonically by an annealing temperature from 0.3546 at 500 °C reaching 0.3722 at 800 °C, very near from the ideal value 0.375. The Zn tetrahedrons become more symmetric and the distortion is gradually relieved by annealing up to 800 °C. Annealing at 900 °C introduces tetrahedron distortion in an opposite way. The zero field cooled (ZFC) and field cooled (FC) magnetization versus the temperature at different applied fields and the magnetization versus the applied field at different temperatures were carried out. The system exhibits a ferromagnetic behavior at room temperature. As the annealing temperature increases from 550 to 900 °C, the saturation magnetization at 300 K increases from 0.0507 to 0.1088 emu/g.     

Structural and Magnetic Properties of (Al/Mg) Co-doped Nano ZnO

The doped ZnO systems Zn_1?x?y Mg _x Al _y O (ZMAO) (x=0, 0.05, 0.1 and y=0, 0.05 and 0.1) were prepared as polycrystalline nanoparticle by a simple sol–gel process. Structural and microstructural analyses were carried out applying X-ray diffraction (XRD) and Rietveld method. Analysis showed that Mg²⁺ and Al³⁺ replace Zn²⁺ substitutionally yielding ZMAO single phase. Replacing Zn⁺² affects the lattice parameters in opposite ways, the parameter c decreases while a increases with an overall decrease in the ratio c/a, which deviates the ZMAO lattice gradually from the wurtzite hexagonal structure. The magnetization versus temperature was measured with zero-field cooled (ZFC) and field cooled (FC) at different applied fields. Also, measurement of magnetization versus applied field was carried out at different temperatures. The system exhibits ferromagnetic properties at room temperature. The saturation magnetization increases as Al doped amount increases.     

The effect of changing the ratios of perovskite triple cations and anions on the optical properties and solar cell performance of perovskite thin films

Journal of Materials Science: Materials in Electronics - (MACl0.33FAPbI3)x(Tri)1?x; (Tri?=?FA0.85MA0.10Cs0.05Pb(Br0.10I0.90)3, x?=?0, 0.05, 0.1, 0.15) perovskite thin...