55 research outputs found
Synthesis and characterization of BaSrTiO3 Perovskite Thin Films Prepared by Sol Gel Technique
Barium strontium Titanate (BST) is a solid solution consist of BaTiO3 and SrTiO3 that mixed with suitable ratio. Barium strontium Titanate oxide (Ba0.8Sr0.2TiO3) thin films prepared by sol gel technique. Barium strontium Titanate thin films deposited on Si substrate and annealing at 400,500, 600 and 700 oC. The characterization of BST film investigated by a different technique, the XRD and SEM revealed the phases, crystal structure and surface topography of the film. XRD pattern shows tetragonal phase for perovskite structure Ba0.8Sr0.2TiO3 with many peaks for different plans. The films annealed at the different temperature that indicated intermediate phases on perovskite structure of Ba0.8Sr0.2TiO3
Effect of High Temperature on Thermal Analysis, Structure and Morphology of CeO2 Nanoparticles Prepared by Hydrothermal Method
Cerium oxide(CeO2) nanoparticles have been prepared by Hydro-Thermal method.The nanoparticles size of cerium oxide was obtained from the solution after drying and heat treatment at a high temperature of 800,900 and 1100 ̊C were in different sizes. The thermal analyses of CeO2 is investigated. The results showed by the x-ray diffractometers that all nanoparticles of cerium oxide have the fluorite crystalline structure. The optical properties showed that the transmittance coefficient decreases with increasing temperatures. There is no significant change in energy band gap where is the increasing sintering temperature
Impact of Molarity on the Structural, Morphological and Optical Properties of CeO2 Thin Films Prepared by Spray Pyrolysis Technique
CeO2 thin films are deposited on glass substrate by spray pyrolysis technique (SPT) at 623 K using different molar concentration of cerium chloride precursor solution. The structural, morphological and optical properties of films were investigated by a set of characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM),UV-VIS-IR. The estimation of crystallite size is 80-120 nm, which is confirmed by Scherer formulae from XRD pattern. XRD analysis shows that the film has cubic fluorite phase with orientation along (111) for all molarity. The optical energy gap decreased with the increase of crystallite size (98-120 nm) due to the size effect
A Study Effect of Irradiation on the Optical Properties of Bi Thin Films
In this work, the effect of irradiation on the optical properties of Bi thin films was studied. The Bi films were deposited on glass substrates at room temperature by thermal evaporation technique with the thickness (0.6 μm) and rate of deposition equal to 6.66 ?/sec. The work had included studying some of the optical properties of Bi thin films before and after irradiation from Co-60 by ray doses (20) Mrad. Analyses performed on irradiated and unirradiated samples showed significant changes in transmittance, transmission spectra. After irradiation, the transmission spectra values increased whereas anisotropy detected in the transmission spectra of unirradiated samples disappeared. The change of color caused by irradiation was noticeable to the naked eye.The optical constants, which are represented by the extinction coefficient (k), and refractive index (n), were determined from the transmittance spectrum in the Near Infrared (2500-3900) nm regions. The value of the optical energy gap increased after irradiation for samples
Effect of RF Sputtered on Characterization of SrTiO3 Thin Film
Thin films of SrTiO3 (STO) were formed on p-type Si(100) substrates using rf magnetron sputtering at different substrate temperatures. The structural and electrical properties were investigated. The thickness of the films was between 300 and 500 nm, and the substrate temperature was always 550°C. The XRD pattern shows the cubic phase for SrTiO3 thin film. Using capacitance-voltage, current-voltage, and admittance spectroscopy, metal-insulator-semiconductor (Al/STO/p- Si/Al) structures were fabricated and characterized. The dielectric constant decreased with increasing frequency. The impedance decreased with increasing frequency
Effect of Sr+ ion Concentration on Microstructure and Dielectric properties of Barium Strontium Titanate Ceramics
Ba1-xSrxTiO3(BST) solid solution with x=0.3,0.4 and 0.5 were prepared by sol-gel method. (Ba, Sr) acetate and Titanate isopropoxide were used as a starting material. XRD patterns confirmed the formation of tetragonal perovskite structure and cubic structure.The FESEM images showed that the particles size reduced when strontium concentration increased. Particles size influence on dielectric constant which observed that with decreasing value dielectric constant due to increased frequency and strontium ion Sr+. The high value of dielectric constant observed at low frequencies and reduced concentration of Sr+
Fabricate and Characterization of SrTiO3-based MIM capacitors
The conventional method uses the stoichiometric mixture of metallic oxides to synthesize polycrystalline SrTiO3. The SrTiO3 was prepared by spin coating to fabricate Metal-Insulator-Matel (MIM) aluminum-SrTiO3 film-aluminum. The cubic structure of the prepared thin film of SrTiO3 was confirmed by X-ray diffraction analysis. Strontium Titanate was deposited on silicon substrates. Studying the effect of the film thickness on the structural and electrical properties. The surface morphology of deposited thin films was studied using a scanning electron microscope. Electrical properties for SrTiO3 films at constant frequency were measured. The electrical conductivity decreases with increasing thickness. The behavior of (capacitance- Frequency) at different thicknesses was discussed. It is noted that the dielectric constant decreases with increasing frequency for all films, and the dielectric constant increases as thickness increases
Optical Properties of Ferroelectric Thin Film Prepared by PLD Technique
Polycrystalline SrTiO3 is synthesized from a stoichiometric combination of metallic oxides by standard ceramic synthesis methods. SrTiO3 thin film X-ray diffraction examination confirmed the cubic structure phase. Strontium Titanate was deposited on the glass substrate. Studying the effect of annealing temperature on the structural properties of the glass of substrate, it is clear that increasing the annealing temperature can improve the crystallinity of SrTiO3 thin films. The surface morphology of the deposited thin films was studied using Scanning Electronic macroscopy; it is observed that the grain size increases with increasing the annealing temperature. The transitions of SrTiO3 films show high transmittance within the wavelength range (300-800nm), making them suitable for antireflection coating in this region. The optical energy gap of SrTiO3 films at various annealing temperatures was measured. It decreases as the annealing temperature of the coatings increases
A novel heat-pulse probe for measuring soil thermal conductivity: Field test under different tillage practices
Accurate soil thermal conductivity (λ) measurements are needed in experimental agri-environmental research. This study design and build of new heat-pulse probe (HPP) based on transient state technology to measure λ. The HPP consists of three main components: an electronic control system, a measurement chamber, and sample rings. The performance of the new HPP for in-situ λ measurements is compared to estimates from measurable soil physical properties (pedotransfer function). Tests were conducted in clay loam and loam soils at three depths. λ measurements by the HPP were affected by tillage practice, fertilizer treatment, soil depth, and soil type. No significant differences in λ measurements by the HPP and estimates from a pedotransfer function were found between tillage practices. There were positive correlations between their values at three soil depths: R2 = 0.92 at 0–5 cm depth, and R2 = 0.88 at both 5–10 and 10–15 cm depths. The standard deviation from the HPP measurements were 0.061, 0.077, and 0.080 W·m−1·K−1 at 0–5, 5–10, and 10–15 cm depths, respectively. In contrast, the pedotransfer function estimates had standard deviations of 0.085, 0.660, and 0.083 W·m−1·K−1, respectively. It was found that conventional tillage increases temperature flow in soils compared to no-tillage because of decreasing soil bulk density (ρb) and consequently higher porosity. The proposed HPP is a low-cost and energy-efficient device, with wide applicability under a range of conditions. It is highly recommended for measuring λ clay loam and loam soils; however, more research is needed to determine its value with other soil types
Evaluation of Water Quality Parameters for Shatt Al-Basrah Canal in Basrah Authorities
A significant increase in freshwater demand has been reported recently due to several factors such as population growth, industrialization, rising living standards and global warming effects. As a direct result of that, numerous water crises have occurred around the world especially in downstream countries such as Iraq. Due to the previous reasons, water in terms of quality and quantity considered as a first priority by the Iraqi government. This study focuses on Basrah city, which is located in the south region. The purpose of this research is evaluating the physicochemical qualities of water from the Shatt Al-Basrah Canal to evaluate its suitability to be used for domestic or industrial uses. Data gathered from two sampling stations located on the canal to measure the physicochemical characteristics of the water such as pH, Ca, Mg, PO4, Cl, SO4, DO, NO3, TDS, and EC. With this specific purpose, water samples were collected from the study area, and the water quality has been evaluated. Water samples were collected during six months period during 2013 for assessment purposes. The results of the analysis were assessed according to international water standards for drinking water. From these results of this study, it is often asserted that there is a water pollution in the Shatt Al-Basrah canal and therefore immediate protective actions need to be utilized to minimize the pollution and improve water quality
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