In this work, the photoluminescence spectra (PL) of porous silicon (PS) have been modified by adding gold nanoparticles (AuNPs) to PS layer. PS was produced via Photo electro-chemical etching (PECE) method of n-type Si wafer with resistivity of about (10 Ω.cm) and (100) orientation. Laser wavelength of (630 nm) and illumination intensity of about (30 mW/cm2), etching current density of (10mA/cm2), and etching time of (4 min) were used during the etching process. The bare PS before metallic deposition process and porous silicon/gold nanoparticles (PS/AuNPs) structures were investigated by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-Ray (EDX). The photoluminescence spectra were investigated as a function of gold nanoparticles sizes and distribution on the surface of PS.
It was found that there are two behaviours were observed for the photoluminescence spectra of PS/AuNPs substrate; quenching and enhancement effects based on the average gold nanoparticles sizes and their aggregation forms.
The utilization of metal oxide nanoparticles, especially zinc oxide, is of a great importance in the medical field because of its physical and chemical properties as well as its antimicrobial potential effects. In our study, the ZnO nanoparticles were synthesized by the precipitation method where pH=14. ZnO nanoparticles were characterized by ultraviolet–visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscope (AFM). Antifungal activity of the ZnO was tested against candida albicans. The results showed that C. albicans (15 samples) became resistant to the fungal activity after testing its sensitivity to several types of fungal antibiotics. UV-vis spectroscopy, XRD, TEM and A
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In this work, nanostructured TiO2 thin films were grown by pulsed laser deposition (PLD) technique on glass substrates. TiO2 thin films then were annealed at 400-600 °C in air for a period of 2 hours. Effect of annealing on the structural and morphological were studied. Many growth parameters have been considered to specify the optimum conditions, namely substrate temperature (300 °C), oxygen pressure (10-2 Torr), laser fluence energy density (0.4 J/cm2), using double frequency Q-switching Nd:YAG laser beam (wavelength 532nm), repetition rate (1-6 Hz) and the pulse duration of 10 ns. The results of the X-ray test show that all nanostructures tetragonal are polycrystalline. These results show that grain size increase fr
... Show MoreIn this work, InSe thin films were deposited on glass substrates by thermal evaporation technique with a deposit rate of (2.5∓0.2) nm/sec. The thickness of the films was around (300∓10) nm, and the thin films were annealed at (100, 200 and 300)°C. The structural, morphology, and optical properties of Indium selenide thin films were studied using X-ray diffraction, Scanning Electron Microscope and UV–Visible spectrometry respectively. X-ray diffraction analyses showed that the as deposited thin films have amorphous structures. At annealing temperature of 100°C and 200°C, the films show enhanced crystalline nature, but at 300°C the film shows a polycrystalline structure with Rhombohedral phase with crystallites size of 17.459 nm. Th
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The change in the optical band gap and optical activation energy have been investigated for pure Poly (vinyl alcohol)and Poly (vinyl alcohol) doped with Aluminum sulphate to proper films from their optical absorption spectra. The absorption spectra were measured in the wave range from (200-700) nm at temperature range (25-140) 0C. The optical band gap (Eg) for allowed direct transition decrease with increase the concentration of Aluminum sulphate. The optical activation energy for allowed direct transition band gap was evaluated using Urbach- edges method. It was found that ?E increases with increasing the concentration of Al2 (SO4)3 and decreases when temperature increases.
In this paper, the effect of both rotation and magnetic field on peristaltic transport of Jeffery fluid through a porous medium in a channel are studied analytically and computed numerically. Mathematical modeling is carried out by utilizing long wavelength and low Reynolds number assumptions. Closed form expressions for the pressure gradient, pressure rise, stream function, velocity and shear stress on the channel walls have been computed numerically. Effects of Hartman number, time mean flow, wave amplitude, porosity and rotation on the pressure gradient, pressure rise, stream function, velocity and shear stress are discussed in detail and shown graphically. The results indicate that the effect of Hartman number, time mean flow, wave a
... Show MoreCutaneous leishmaniasis (CL) is the most form of leishmaniasis disease prevalent in Iraq. CL remains a public health problem in numerous endemic countries because of the absence of safe, effective, and high-cost drugs for treatment. Macrophages are the main inhabitant cell for Leishmania; they phagocyte and allow parasite multiplying. Phagocytosis and anti-leishmanial activity of macrophage are the main factors in the elimination of Leishmania parasites. Phagosome-resident amastigotes also evade innate host defense mechanisms. Silver nanoparticles (Ag NPs) have an important effect in stimulating the production of oxygen species. The objective of this study was to examine macrophages cytotoxicity upon exposure to L. tropica and Ag NPs. Se
... Show MoreIn this paper, magnesium oxide nanoparticles (MgO NPS) have been prepared and characterized and its concentration effect has been studied on polymers surface (MgO NPS). The results showed that the degradation of poly methyl methacrylate increased when using such metal oxide. The results also showed that the metal oxide increased the degradation of poly methyl methacrylate. X-ray diffraction, scanning electron microscopy, atomic force microscopy were used to study the morphological characteristics and size of nano MgO particles analysis. Films were prepared by mixing the different masses of MgO NPS (0.025, 0.05, 0.1, 0.2 and 0.4) % with a polymer solution ratio (W/V) 7 %. Photo-
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Thin films of zinc selenide ZnSe have been prepared by using thermal evaporation method in vacuum with different thickness (1000 – 4000) Ao and a deposited on glass substrate and studying some electrical properties including the determination of A.C conductivity and real, imaginary parts of dielectric constant and tangent of loss angle. The result shows that increasing value of A.C conductivity with increasing thickness and temperature, and increasing capacitance value with increasing the temperature and decrease with increasing frequency . Real and imaginary parts of dielectric constant and tangent of loss angle decrease with increasing frequency
Diabetic foot is a catastrophic complication of diabetes. This study included isolation and identification of three types of bacteria that cause diabetic foot ulcers, fifty-five isolates of Staphylococcus aureus, thirty-five isolates of Acinetobacter baumannii, and thirty isolates of Serratia marcescens. These isolates were obtained from diabetic foot patients at different private clinics in and around Baghdad and Medical City Hospital. The proportion of male patients was greater than females, and it was noted that the age group (51-68 years) was more ages affected by diabetic foot. These isolates showed high resistance to most of the antibiotics used, Staphylococcus aureus was resistant to
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Transient mixed convection heat transfer in a confined porous medium heated at periodic sinusoidal heat flux is investigated numerically in the present paper. The Poisson-type pressure equation, resulted from the substituting of the momentum Darcy equation in the continuity equation, was discretized by using finite volume technique. The energy equation was solved by a fully implicit control volume-based finite difference formulation for the diffusion terms with the use of the quadratic upstream interpolation for convective kinetics scheme to discretize the convective terms and the temperature values at the control volume faces. The numerical study covers a range of the hydrostatic pressure head , , , , and ), sinusoidal amplitude range of
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