The influence of Cr3+ doping on the ground state properties of SrTiO 3 perovskite was evaluated using GGA-PBE approximation. Computational modeling results infered an agreement with the previously published literature. The modification of electronic structure and optical properties due to Cr3+ introducing into SrTiO 3 were investigated. Structural parameters assumed that Cr3+ doping alters the electronic structures of SrTiO 3 by shifting the conduction band through lower energies for the Sr and Ti sites. Besides, results showed that the band gap was reduced by approximately 50% when presenting one Cr3+ atom into the SrTiO 3 system and particularly positioned at Sr sites. Interestingly, substituting Ti site by Cr3+ led to eliminating the band gap indicated a new electrical case of transferring semiconducting material into a conducting material which intern enhance conductivity. Furthermore, it was found that Cr 3+ doping either at Sr or Ti positions could effectively develop the SrTiO3 dielectric constant properties. In addition, the absorption spectra was extended to cover the visible light region of the electromagnetic radiation, indicating the capability of this compound in harvesting sunlight for solar cell applications. Consequently, it can be said that Cr 3+ is an effective dopant which opening up new prospects for various industrial and technological applications.
In this paper three techniques for image compression are implemented. The proposed techniques consist of three dimension (3-D) two level discrete wavelet transform (DWT), 3-D two level discrete multi-wavelet transform (DMWT) and 3-D two level hybrid (wavelet-multiwavelet transform) technique. Daubechies and Haar are used in discrete wavelet transform and Critically Sampled preprocessing is used in discrete multi-wavelet transform. The aim is to maintain to increase the compression ratio (CR) with respect to increase the level of the transformation in case of 3-D transformation, so, the compression ratio is measured for each level. To get a good compression, the image data properties, were measured, such as, image entropy (He), percent r
... Show MoreIn this research, A thin film of Rhodamine B dye and TiO2 Nanoparticles doped in PMMA Polymer has been prepared by a casting method. The sample was spectrum absorption by UV-Vis. The nonlinear optical properties were measured by Z- scan technique using Nd:YAG laser with (1064 nm) wavelength. The nonlinear refractive index (n2) and nonlinear absorption coefficient (β) were estimated for the thin film for different energies of the laser, n2 and β were decreased with increasing intensity of incident laser beam. Also, the type of β was two-photon absorption and n2 negative nonlinear reflective.
We have studied the effect of gamma irradiation on the optical transmission, absorbance, absorption coefficient, and Urbach energy for (PMMA- doped red methyl) film deposited by using solvent casting method .The optical transmission (T %) in the wavelength range (1901100 ) nm of films was measured , it was seen that all the parameters were affected by gamma irradiation.
Pure blend (PC-PS) and doped blend films with various volume ratio of Coumarin dye were prepared by using casting method. The absorption and transmission spectra for these films were measured using UV/VIS spectrometer technique in order to assessment the type of transition which was found to be indirect transition. The optical energy gap of pure PC was (4.24) eV, pure PS was (4.39) eV, Coumarin dye was (4.08) eV, and pure blend was (4.1) eV. After doping blend with Coumarin dye; the energy gap decreases by (0.06) eV in volume ratio (12) ml. The results showed that absorption coefficient and refractive index affects by doping. When adding the Coumarin dye to the pure blend with different concentrations (12, 24, 36, and 48) ml, the FTIR sp
... Show MoreIn the present work, poly methyl methacrylate (PMMA) doped with Rhodamine 6G was prepared. The spectral properties (absorption and fluorescence) of the films were studied at different concentrations (1x10-5, 2x10-5, 5x10-5, 7x10-5, and 1x10-4mol/l). The investigated samples were made in the form of thin films. This was achieved by dissolving a certain weight of PMMA in a fixed volume of chloroform, composite films was with thickness (25.8μm) at room temperature. The achieved results were pointed out that absorption and fluorescence spectra have taken a wide spectral rang so when increased the concentratio
... Show MoreProverbs are considered as a major source of ancient events and happenings. Similar to other past events related to life, proverbs have many important and famous values in people's life. This study will shed lights on the use of proverbs as short sentences based on long experiences. The aim of the study is to explicate the roles, and the importance of proverbs in our life and how they are used to convey thoughts to people throughout simple words with denotation. Thus, proverbs explicate the truth and experience of our grandfathers when directed for criticism. Few proverbs were used by writers to criticize, mimic and reprint their personalities. Hence, proverbs will achieve portions of the unique roles of understanding. The model to
... Show MoreThe aim of the work is the synthesis and characterization of the tridentate Schiff base (HL) containing (N and O) as donor atoms type (ONO). The ligand is: (HL) phenyl 2-(2-hydroxybenzylidenamino)benzoate This ligand was prepared by the reaction of (phenyl 2-aminobenzoate) with salicylaldehyde under reflux in ethanol and few drops of glacial acetic acid which gave the ligand (HL). The prepared ligand was characterized by (FT IR,UV–Vis) spectroscopy, Elemental analysis of carbon, hydrogen and nitrogen (C.H.N.) and melting point. The ligand was reacted with some metal ions under reflux in ethanol with (1 metal :2 ligand )mole ratio which gave complexes of the general formula: Pr III , Cr and III La III [M(L)2]Cl , M = Products were found to
... Show MoreDelays and disruption are a common issue in both community and personal building programs The problem exists all throughout the world, but it is particularly prevalent in Iraq, where millions of dollars are squandered each time as a outcome. Delays and interruptions may have serious consequences not just for Iraq's construction plans, but also for the country's economic and social status. While numerous studies have been conducted to investigate the factors driving delays and disruption in Iraqi construction projects, slight consideration has been given to by what means project management implements and approaches have affected the occurrence of project delays and disruption. After analyzing the crucial reasons for delays and instability in
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