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Ab–Initio large unit cell calculations of the electronic structure of Si and Ge nanocrystals
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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.

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Publication Date
Fri Jun 24 2022
Journal Name
Iraqi Journal Of Science
Comparison of Physical Properties, Energetic, Vibration Frequencies and Normal Coordinates, for Construction Units of Fullerene C60 Using Quantum Mechanical Calculations
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PM3 semiempirical method and Density Functional Theory (DFT) calculations of the type (B3LYP) and a Gaussian basis set (6-311G) were carried out for fullerene C60 molecule with its construction units (5radialene, 1,2,3-trimethylene indan, and corannulene), to evaluate the geometrical structure (bond lengths, symmetry, and energetic such as heat of formation ΔH0f, total energy Etot., dipole moment μ, EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), energy gap ΔEHOMO-LUMO), the distribution of electron density and vibration frequencies, all at their equilibrium geometries. Assignment of the vibrations modes was done according to the movement of the atoms as a result of DFT calculatio

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Publication Date
Mon Apr 10 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Morphological Description and Histological Structure of Kidney in Barn Owl Tyto alba
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  The morphological description and histological structure of Kidney in barn owl Tyto alba have been invesigated. The results of present study revealed that barn owl has pair of elongated solid kidney situated symmetrically on both sides of vertebral column. Each kidney consists of three lobes represented by carnial, middle and caudal lobes and all of then covered by a capsule of connective tissue.     Microscopical examination showed that the basic unit of kidney in barn owl represented by lobules which have conical shaped and each of them consists of cortex and medulla, and the cortex occupies more area than that of medulla. The results of the present study revealed that the glomerulus in barn owl represented b

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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
Virtual ( Electronic ) Reference Services In Academic Libraries: Virtual ( Electronic ) Reference Services In Academic Libraries
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Abstract
This paper deals with the concept of electronic reference services in academic
libraries , showing forms of communications , training needs for reference librarians
and the role of the librarian in the new technological environment.

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Publication Date
Tue Jan 01 2019
Journal Name
Izvestiya Of Saratov University. New Series. Series: Philology. Journalism
To the Question of Internal Inflection of the Roots in Arabic and Russian (Inflected Analysis of the Root Structure)
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Publication Date
Wed Jan 02 2019
Journal Name
Journal Of Educational And Psychological Researches
The Effectiveness of an Educational Unit According To the Constructive Strategy in Developing Thinking Skills for Fifth Primary Students
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    The current phase distinguish by the rapid scientific development, which pushes individuals to have the necessities of scientific and practical life through the proper scientific thinking which contribute to the development of invention and creativity away from memorizing and indoctrination and encouraging individuals to looking for information and then attempting to process and develop these information instead of being a passive receiver. The investment of minds becomes the logical investment in all societies by preparing the citizen to become able to face life changes and its necessities. It is very important to take care of individuals and develop their mental abilities and thinking skills. The constructive strateg

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Publication Date
Fri Apr 01 2016
Journal Name
Al–bahith Al–a'alami
Journalism of Paper Newspapers in Light of the Competition of the Electronic Press / (A Field Study of Yemeni Daily Newspapers)
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The researcher seeks to get scientific facts through knowing the relationship between the priorities of Yemeni audience in follow-up paper daily newspapers compared to surfing publics the online journalism sites and the nature of information obtained from online journalism sites and printed paper newspapers and the impact of the daily newspapers in the priority of issues and political events among a sample of a group of Yemeni readers in order to identify the extent to keep up the paper daily newspapers of the development in the field of online journalism and the extent of reading paper newspapers under the intense competition by online journalism sites, and are paper newspapers able to keep pace with the actual developments provided by

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Crossref
Publication Date
Sun Feb 01 2015
Journal Name
International Journal Of Computer Science And Mobile Computing
Electronic Commerce Obstacles for Educated Iraqi Women
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Electronic Commerce (EC) is an important field due to the many advantages it involves. This study aims to discuss the constraints surrounding educated Iraqi women which results overall lack of entering the EC and to give us additional insight into why they are avoiding entering this world. Results reveal that lack of awareness, lack of government policy and support, language, security and trust are the most important factors that contributes to EC adoption in addition to many other factors

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Publication Date
Sun Feb 20 2022
Journal Name
Papers In Physics
Electronic and optical properties of nickel-doped ceria: A computational modelling study
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Cerium oxide CeO2, or ceria, has gained increasing interest owing to its excellent catalytic applications. Under the framework of density functional theory (DFT), this contribution demonstrates the effect that introducing the element nickel (Ni) into the ceria lattice has on its electronic, structural, and optical characteristics. Electronic density of states (DOSs) analysis shows that Ni integration leads to a shrinkage of Ce 4f states and improvement of Ni 3d states in the bottom of the conduction band. Furthermore, the calculated optical absorption spectra of an Ni-doped CeO2 system shifts towards longer visible light and infrared regions. Results indicate that Ni-doping a CeO2 system would result in a decrease of the band gap. Finally,

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Publication Date
Sun Feb 20 2022
Journal Name
Papers In Physics
Electronic and optical properties of nickel-doped ceria: A computational modelling study
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Cerium oxide (CeO2), or ceria, has gained increasing interest owing to its excellent catalytic applications. Under the framework of density functional theory (DFT), this contribution demonstrates the eect that introducing the element nickel (Ni) into the ceria lattice has on its electronic, structural, and optical characteristics. Electronic density of states (DOSs) analysis shows that Ni integration leads to a shrinkage of Ce 4f states and improvement of Ni 3d states in the bottom of the conduction band. Furthermore, the calculated optical absorption spectra of an Ni-doped CeO2 system shifts towards longer visible light and infrared regions. Results indicate that Ni-doping a CeO2 system would result in a decrease of the band gap. Finally,

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Publication Date
Fri Jul 01 2011
Journal Name
Materials Chemistry And Physics
Gadolinium substitution and sintering temperature dependent electronic properties of Li–Ni ferrite
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Scopus (61)
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