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.
A theoretical model is developed to determine time evolution of temperature at the surface of an opaque target placed in air for cases characterized by the formation of laser supported absorption waves (LSAW) plasmas. The model takes into account the power temporal variation throughout an incident laser pulse, (i.e. pulse shape, or simply: pulse profile).
Three proposed profiles are employed and results are compared with the square pulse approximation of a constant power.
This study is dedicated to solving multicollinearity problem for the general linear model by using Ridge regression method. The basic formulation of this method and suggested forms for Ridge parameter is applied to the Gross Domestic Product data in Iraq. This data has normal distribution. The best linear regression model is obtained after solving multicollinearity problem with the suggesting of 10 k value.
Background: Parotid gland tumors account for 80% of all salivary gland neoplasms, 20% of these are malignant, but in daily clinical practice most parotid masses are operated on before obtaining the final histological diagnosis. This clinical setting further complicates the critical point of parotid surgery, which is the management of the facial nerve. Materials and methods: 45 patients underwent parotidectomy for benign and malignant neoplasms. A complete history is collected from the patients with the duration and the site of the tumor, the facial nerve examined and its associations, a medical consultation done for opinion and management. Clinical examination with facial nerve was mandatory to avoid any mistakes that may occur. The most si
... Show MoreThe research, which was drawn from his doctoral thesis (People's Policy towards Vietnam 1949-1979), discussed the roots of the connections between the Chinese and Vietnamese communists since the 1920s, the presence of Ho Chi Minh and other Vietnamese communists in China, their influence by the revolutionary struggle of the Chinese Communist Party and their establishment of a group of The Vietnamese Revolutionary Societies and the Indo-Chinese Communist Party until the outbreak of the Vietnamese Revolution and their success in declaring the establishment of the Democratic Republic of Vietnam in 1946. Keywords: Ho Chi Minh, Chinese Communist Party, Indo-Chinese Communist Party, Democratic Republic of Vietnam, Chou En Lai.
New Schiff bases derived from D-galactose were synthesized by condensation of aldehyde (1,2:3,4-Di-O-isopropylidene-6-carboxaldehyde-α-D-galactopyranose) with different aromatic amines such as (4-bromo, 3-hydroxy, 4-iodo, 4-methoxy) aniline in dry benzene using glacial acetic acid as a catalyst. These compounds were converted to oxazepine derivatives by addition reaction with maleic anhydride in dry benzene as a solvent. The structures of the synthesized compounds have been characterized by elemental analysis, FTIR spectra, some of them by using 1HNMR spectra and measurement of its physical properties.
During a period of two years, from January 1995 till December 1996, the first survey on fish parasites in Bahr Al-Najaf depression, mid Iraq, was achieved. A total of 6992 fishes, belonging to 11 species, were collected and inspected for external and internal parasites. These fishes were infected with three protozoans (Ichthyophthirius multifiliis, Trichodina domerguei and Myxobolus pfeifferi), two monogeneans (Dactylogyrus cornu and Gyrodactylus elegans), two digenetic trematodes (Clinostomum complanatum and Ascocotyle coleostoma), one nematode (Contracaecum sp.) and one acanthocephalan (Neoechinorhynchus iraqensis). Five fish species were recorded as new h
... Show MoreIn this study, Cr−Mo−N thin films with different Mo contents were synthesised via closed field unbalanced magnetron sputtering ion plating. The effects of Mo content on the microstructure, chemical bonding state, and optical properties of the prepared films were investigated by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy, and ultraviolet-visible spectrophotometry. XRD results determined the face centered cubic (fcc) structure of pure CrN film. The incorporation of molybdenum (Mo) in the CrN matrix was confirmed by both XRD and XPS analyses. The CrMoN coatings demonstrate various polycrystalline phases including CrN, γ-Mo2N, Cr with oxides layers of MoO3, CrO3
... Show MoreGypseous soil is considered as a problematic soil for embankment construction, however, implementation of emulsified asphalt as a stabilization agent could be a proper solution for enhancing its properties as a subgrade soil. In this work, the sustainability of asphalt stabilized soil has been assessed in terms of its resistance to cyclic (freezing-thawing) and (heating-cooling) processes. Specimens have been prepared at optimum fluid content (moisture and emulsion) and tested under direct shear stresses while subjected to 30 cycles of (freezing-thawing) and (heating-cooling). Both of dry and soaked testing conditions have been implemented. Data have been observed after each 10 cycles, and compared with that of reference mix. It was conclud
... Show MoreThis paper represents an experimental study on the application of smart control represented by the use of the fuzzy logic controller. Two-link flexible manipulators that are used in airspace and military applications are made of flexible materials characterized by low frequency and damping ratio. To solve this problem, this paper proposes the use of smart materials (piezoelectric transducers), where each link is bonded with a pair of piezoelectric transducers that act as a sensor and another as an actuator. As the arm vibrates because of the movement generated by the motor, this voltage is controlled by a regulator inside the LABVIEW® 2020 software and sends the output control voltage to the piezoelectric actuator. Experimental results
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