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1 - Investigation of dopant centres dominating the conduction process in the bulk of un-doped GaSb
Megersa Wodajo ShuraAbstractIn this paper, first, the theoretical description of the effects of the dopant densities and the activation energies on the ionization densities, the chemical potentials corresponding to each dopant levels, the majority carrier densities and the Fermi-energy lev أکثرAbstractIn this paper, first, the theoretical description of the effects of the dopant densities and the activation energies on the ionization densities, the chemical potentials corresponding to each dopant levels, the majority carrier densities and the Fermi-energy levels in one-acceptor-level system, highly compensated system and two-acceptor-level system are described in detail. Upon fitting the theoretical to the experimental results obtained by the temperature-dependent Hall effect measurements for three samples of un-doped GaSb, the dopant densities and the activation energies for a system with different dopants are investigated. The obtained results revealed that the dopant activation energy has less (no) effect on the Fermi-energy level and the majority carrier density in the highest temperature regimes. The doping density has also less (no) effect on the Fermi-energy level in the lowest temperature regimes. Finally, fitting of the theoretical to the experimental Hall effect measurements results confirmed the presence of three acceptor and one donor levels dominating the majority carrier densities at different temperature regions in all the samples of un-doped GaSb semiconductor. تفاصيل المقالة -
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2 - Computational study of chemical properties of Captopril drug and the connected form to Fullerene (C60) as a medicine nano carrier
Roya AhmadiIn this research at the first, captopril drug (CA) and its fullerene connected form (FCA) wereoptimized. Natural Bond Orbital (NBO) calculations for these compounds were carried out at theB3LYP/6-31G quantum chemistry level, in the gas phase and the liquid phase. These أکثرIn this research at the first, captopril drug (CA) and its fullerene connected form (FCA) wereoptimized. Natural Bond Orbital (NBO) calculations for these compounds were carried out at theB3LYP/6-31G quantum chemistry level, in the gas phase and the liquid phase. These calculations canbe performed at different accuracy levels depending on the aim of the theoretical study [1]. Forinstance, Density Functional Theory (DFT) can be used to calculate an accurate electronic structure,HOMO and LUMO energies, Mulliken charge of atoms, energetic_orbital levels, chemical hardness,chemical potential and electrophilicity of systems, and finally chemical, physical, biological,pharmacological and industrial of fullerene and fullerene derivatives [47]. Theoretical calculationssuch as NBO are very important to understand the pathways of electron transfer in assemblies.Consequently, the obtained results showed that energy orbital levels decreased considerably bylinking structure of Captopril to structure of fullerene C60. In the study some other characteristicssuch as chemical potential, chemical hardness, electrophilicity in these structures; it was found thatthey changed considerably. These changes show dependency of the results, on power of electronaffinity of C60. In another part, the valence electrons populations for carbons, nitrogen, oxygens andhydrogens atoms in similar position for FCA and CA were compared. Finally the data were comparedand discussed. تفاصيل المقالة -
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3 - Efficiency Measurement in Two-Stage Network Structures Considering Undesirable Outputs
AR. Amirteimoori A. Tolooei Eshlaghi‎ M. HomayounfarData envelopment analysis (DEA) has been proven as an excellent data oriented nonparametric technique to evaluate the relative performance of peer decision making units. Since DEA is introduced in 1978, it has been widely applied to measure the efficiency of a wide va أکثرData envelopment analysis (DEA) has been proven as an excellent data oriented nonparametric technique to evaluate the relative performance of peer decision making units. Since DEA is introduced in 1978, it has been widely applied to measure the efficiency of a wide variety of production and operation systems. Recently DEA has been extended to examine the efficiency of decision making units (DMUs) with two-stage network structures or processes, where the outputs from the first stage are intermediate measures that make up the inputs of the second stage. Many researchers developed several DEA based models for evaluating the efficiencies of such systems. This paper considers the performance evaluation of the general two-stage network structures, while each stage may produce undesirable outputs (bad outputs), in addition to desirable and goos outputs. The applicability of the approach in this paper is illustrated by using the Green Hen poultry chain data in Guilan province, Iran. تفاصيل المقالة