Ab – initio restricted Hartree - Fock method within the framework of large unit cell (LUC) formalism is used to investigate the electronic structure of Si and Ge nanocrystals. The surface and core properties are investigated. A large unit cell of 8 atoms is used in the present analysis. Cohesive energy, energy gap, conduction and valence band widths are obtained from the electronic structure calculations. The results are compared with available experimental data and theoretical results of other investigators. The calculated lattice constant is found to be slightly larger than the corresponding experimental value because we use only 8 atoms and we compared the results with that of the bulk crystals, nanoclusters are expected to have stronger directional bonds that in their bulk structure. The surface states are found to be mostly non-degenerated because of the effect of surface discontinuity and the existence of oxygen atoms. Valence and conduction bands are found to be wider on the surface due to the splitting of energy levels due to the existence of oxygen atoms. The present method can be used to investigate the electronic structure of bulk, surface and nanocrystals.
Objective: Per-implantitis is one of the implant treatment complications. Dentists have failed to restore damaged periodontium by using conventional therapies. Tissue engineering (stem cells, scaffold and growth factors) aims to reconstruct natural tissues. The paper aimed to isolate both periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMMSCs) and use them in a co-culture method to create three-layered cell sheets for reconstructing natural periodontal ligament (PDL) tissue. Materials and methods: BMMSCs were isolated from rabbit tibia and femur, and PDLSC culture was established from the lower right incisor. The cells were co-cultured to induce BMMSC differentiation into PDL cells. Cell morphology, stem cel
... Show MoreThe research Was based to on a real problem and realistically of represented by that Iraqi Airways company does not have the electronic cost accounting system and therefore be the process of the pricing various services provided by a company sample research respecting air transport and air cargo and aviation fuel and services and catering are not properly especially in the presence of new data from the new companies entering competition in Iraqi aviation industry and therefore does not provide price flexibility in order to compete in getting market share, And then research this problem addressed through design an electronic cost Accounting system covers all the costs incurred by the compan
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This research aims to determine the nature of tacit knowledge relationship and its impact on building the electronic human resources management, as it constitutes the most prominent tacit knowledge resources owned by the Organization for being a stand out in the skill, knowledge and intellectual capacity of human resources, as the electronic human resources management is a contemporary trend that adopted by the organization in the performance of all tasks and duties related workers have remained in the contemporary environment in which it operates.
and have indicated the research problem to the low level of awareness of the ad
... Show MoreBackground: Prematurity and its complications are the major causes of neonatal and infant morbidity and mortality. Although the cause of preterm labor is often unknown, numerous etiological risk factors may be implicated. To identify the risk factors that lead to prematurity and assess the neonatal outcomes that preterm neonates may develop. Methods: This case-control study was conducted at AL-Elwiya Pediatric Teaching Hospital, Baghdad, Iraq, from the 1st of June to the 31st of December 2019. A non-randomized sample of 700 neonates admitted to the neonatal care unit was included in this study and divided into two groups of preterm full-term neonates as the experimental and control groups, respectively (n=350 each). The same questionnaire w
... Show MoreThe liver of marsh harrier grossly appeared as large, bi-lobed organ divided into left and right lobes, which are approximately equal in size and not divided into secondary lobes. Histologically, the liver of marsh harrier was found to contain numerous lobules which are not well defined by the connective tissue of the septa except that surrounded the portal triads. The parenchyma of liver composed of irregular branching cords of hepatocytes organized in double rows alternating with tortures path sinusoids which are lined with flattened endothelial cells and large, irregular outlined kupffer cells. Hepatic cords arranged in a radial pattern around the central vein of the liver lobule while in a subscapsular region they run parallel to the ca
... Show MoreHighlighting the role of the movement and its dramatic dimensions, as an artistic product, whether at the level of cinema or television in general, and the stages of its influence within the structure of the cinematographic scene in particular, had an effective role in the continuation of the structure of the event according to its dramatic and aesthetic process, and from this the research problem crystallized in the following question: What is How the kinetic diversity of the camera in the structure of the cinematographic scene is achieved to achieve the maximum possible benefit by extrapolating all opinions in line with the objectives of the research, the research presented and two topics and the introduction were divided, which
... Show MoreVibration is a source of energy that can be beneficial or harmful based on the application. Vibration can affect the function of any structure; however, Ceramic matrix composite (CMC) is one of these structures. Whereby less studies have been concentrated on study its function specially when electromagnetic wave (microwave) exposed on its surface to perform its designed function. To address this concept, SiC composite has been fabricated which is designed to have a transparent characteristics to microwave. External vibration had been applied on its surface to monitor how much influence could nanoscale amplitude vibration damage the microwave interaction. The source of vibration was applied from piezoelectric and the vibration was monitored
... Show MoreThis research was conducted to study the histological structure of the eye in the tree frog (Hyla arborea savignyi) and showed that it is composed of the eyeball and the lens and optic nerve. Appeared eyeball is surrounded by three Tunica from the inside to the outside are Tunica Interna, Tunica vasculosa, Tunica fibrosa. The tunica interna consists of the retina that consists of 10 layers are from outer to inner pigment epithelial layer, rods and cones layer, external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer , ganglion cells layer , nerve fibers layer, internal limiting membrane .The vascular tunic or Uvea consists of the choroid, ciliary body , and iris . The fibrous coat co
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