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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
Tue Apr 02 2024
Journal Name
Iraqi Journal Of Applied Physics
Effect of Substrate Temperature on Characteristics and Gas Sensing Properties of Nb2O5/Si Thin Films
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Thin films of Nb2O5 have been successfully deposited using the DC reactive magnetron sputtering technique to manufacture NH3 gas sensors. These films have been annealed at a high temperature of 800°C for one hour. The assessment of the Nb2O5 thin films structural, morphological, and electrical characteristics was carried out using several methods such as X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), Hall effect measurements, and sensitivity assessments. The XRD analysis confirms the polycrystalline composition of the Nb2O5 thin films with a hexagonal crystal structure. Furthermore, the sensitivity, response time, and recovery time of the gas sensor were evaluated for the Nb2O5 thin film

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Publication Date
Sun Jan 01 2023
Journal Name
3rd International Conference On Smart Cities And Sustainable Planning
Theoretical structure of apparent and latent in the urban townscape: Subject review
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Publication Date
Thu Aug 06 2020
Journal Name
Cuestiones Políticas
Political structure and the administration of political system in Iraq (post-ISIS)
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The objective of the investigation was to analyze the structure and administration of the political system in Iraq (post-ISIS). After 2003, the Iraqi political system suffered the fundamental problem of its failure to achieve the political and social inclusion that characterizes democratic systems, to guarantee the establishment of a "state for all", while respecting differences. Political representation has moved from the system of sectarian ethnic components, under the title of consensual democracy, to the representation of leaders and the realization of their interests and the interests of their parties at the expense of the groups that claim to represent them, which complicates the problem. In this sense, the new political syste

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Publication Date
Sat Oct 01 2011
Journal Name
Iraqi Journal Of Physics
The Structure and Electrical Properties of Porous Silicon Prepared by Electrochemical Etching
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Porous silicon was prepared by using electrochemical etching process. The structure, electrical, and photoelectrical properties had been performed. Scanning Electron Microscope (SEM) observations of porous silicon layers were obtained before and after rapid thermal oxidation process. The rapid thermal oxidation process did not modify the morphology of porous layers. The unique observation was the pore size decreased after oxidation; pore number and shape were conserved. The wall size which separated between pore was increased after oxidation and that effected on charge transport mechanism of PS

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Publication Date
Thu Jun 02 2016
Journal Name
Alustath Journal For Human And Social Sciences
Islamic Electronic Libraries and The service for downloading Research and Comic books (PDF): An Evaluation study
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The research aims to evaluate Islamic electronic libraries and their service for downloading research and illustrated books, explaining their origins, features and types. The research was limited to the libraries available on the Internet that provide the service for downloading research and illustrated books. The researcher relied on the survey approach to identify the libraries and a sample of them (20 libraries) was selected. For the purpose of evaluating it according to five criteria related to the preparation and publication of Islamic electronic libraries (the responsible party, the goals and objectives, the year, the services it provides, the sections and subject specializations of its contents) and five criteria related to the servi

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Publication Date
Sun Aug 06 2023
Journal Name
Karbala International Journal Of Modern Science
Improving the BURT’s Sensitivity using Noise Calibration Unit via Crab Nebula Observations
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Radio observations from astronomical sources like supernovae became one the most important sources of information about the physical properties of those objects. However, such radio observations are affected by various types of noise such as those from sky, background, receiver, and the system itself. Therefore, it is essential to eliminate or reduce these undesired noise from the signals in order to ensure accurate measurements and analysis of radio observations. One of the most commonly used methods for reducing the noise is to use a noise calibrator. In this study, the 3-m Baghdad University Radio Telescope (BURT) has been used to observe crab nebula with and without using a calibration unit in order to investigate its impact on the sign

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Publication Date
Sun Aug 06 2023
Journal Name
Karbala International Journal Of Modern Science
Improving the BURT’s Sensitivity using Noise Calibration Unit via Crab Nebula Observations
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Radio observations from astronomical sources like supernovae became one the most important sources of information about the physical properties of those objects. However, such radio observations are affected by various types of noise such as those from sky, background, receiver, and the system itself. Therefore, it is essential to eliminate or reduce these undesired noise from the signals in order to ensure accurate measurements and analysis of radio observations. One of the most commonly used methods for reducing the noise is to use a noise calibrator. In this study, the 3-m Baghdad University Radio Telescope (BURT) has been used to observe crab nebula with and without using a calibration unit in order to investigate its impact on the sign

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Publication Date
Sun Mar 04 2018
Journal Name
Iraqi Journal Of Science
Energy Band Diagram of NiO: Lu2 O3/n-Si heterojunction
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Crystalline NiO and doped with rare earth lutetium oxide (Lu2O3) at (6%wt)., have been prepared by pulsed laser deposition (PLD), The Q-switched Nd:YAG laser beam was incident at an angle of 45° on the target surface, and the energy of the laser was 500 mJ, wavelengths of 532nm, and frequency 6Hz. XRD pattern shows all doped and undoped films are polycrystalline, and cubic structure. The 200nm thin NiO showed an average optical energy band gap of 3.4eV, and increase with doping at 6% Lu2O3. The Hall Effect measurements confirmed that holes were predominant charges in the conduction process (i.e p-type). D.C conductivity measurements with temp-erature (T), show

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Publication Date
Thu Sep 13 2018
Journal Name
Baghdad Science Journal
Study of the Electric Quadrupole Moments for some Scandium Isotopes Using Shell Model Calculations with Different Interactions
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The electric quadrupole moments for some scandium isotopes (41, 43, 44, 45, 46, 47Sc) have been calculated using the shell model in the proton-neutron formalism. Excitations out of major shell model space were taken into account through a microscopic theory which is called core polarization effectives. The set of effective charges adopted in the theoretical calculations emerging about the core polarization effect. NushellX@MSU code was used to calculate one body density matrix (OBDM). The simple harmonic oscillator potential has been used to generate the single particle matrix elements. Our theoretical calculations for the quadrupole moments used the two types of effective interactions to obtain the best interaction compared with the exp

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Publication Date
Mon Aug 01 2011
Journal Name
Journal Of Engineering
DESIGN OF A CONTINUOUS SLIDING MODE CONTROLLER FOR THE ELECTRONIC THROTTLE VALVE SYSTEM
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Lowering the emission, fuel economy and torque management are the essential
requirements in the recent development in the automobile industry. The main engine control
input that satisfies the above requirements is the throttling angle which adjusts the air mass
flow rate to the engine port. Due to the uncertainty and the presence of the nonlinear
components in its dynamical model, the sliding mode control theory is utilized in this work
for the throttle valve angle control system to design a robust controller for this system in the
presence of a nonlinear spring and Coulomb friction. A continuous sliding mode control law
which consists of a saturation function, instead of a signum function, and the integral of
ano

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