Ghasem Forozani; Dastan Hormozinejad
Abstract
Graphene, with its exceptional properties, is pivotal in modern technologies. However, its zero band gap limits advanced applications like optoelectronics and quantum computing. This study investigates doping graphene with group III elements (boron, aluminum, gallium, and indium) to enhance its properties. ...
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Graphene, with its exceptional properties, is pivotal in modern technologies. However, its zero band gap limits advanced applications like optoelectronics and quantum computing. This study investigates doping graphene with group III elements (boron, aluminum, gallium, and indium) to enhance its properties. Using DFT and LDA in Quantum Espresso, along with BURAI and YAMBO tools, structural and electronic properties were analyzed. Moderate boron doping (~16.68%) introduced a 0.6-0.8 eV band gap, while high gallium doping (50%) achieved ~2 eV, enhancing visible light absorption. Aluminum and indium doping improved optoelectronic properties, with indium increasing states near the Fermi level and infrared absorption. Molecular dynamics confirmed doping preserves graphene’s structural stability and performance. This work highlights the potential of precise doping to optimize graphene for sensors, optoelectronic devices, and quantum technologies.
zohre Ahmadi Beni; Ebrahim Sadeghi; Kavoos Abbasi
Abstract
A two-electron quantum disc under harmonic confinement potential and uniform magnetic field normal to surface disc is considered. In this regard, a change of variable is used and the total Hamiltonian is divided into center of mass and relative part Hamiltonians. The Schrodinger equations of each part ...
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A two-electron quantum disc under harmonic confinement potential and uniform magnetic field normal to surface disc is considered. In this regard, a change of variable is used and the total Hamiltonian is divided into center of mass and relative part Hamiltonians. The Schrodinger equations of each part are analytically solved and wave functions and eigen values energy are obtained. To study the tunneling effect, a constant confinement potential for barrier region is considered and the quantum transmission coefficient in terms of height and barrier width and magnetic field is calculated. Results show the transmission coefficient decreases with increase the height and width barrier and increases with magnetic field
Seyedeh Masoumeh Moosavi Mehmandosti; Marjaneh Jafari Fesharaki; Mohammad Reza Jalali
Abstract
In this study SrZrO3:xEu3+(x=0.1-0.5 mol%) nanophosphor was prepared by celf-combustion sol-gel method with citric acid as fuel at 350 °C. The results of X-ray diffraction (XRD) indicated the optimum temperature to form a single-phase of nanophosphors with perovskite crystal structure was 900 °C. ...
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In this study SrZrO3:xEu3+(x=0.1-0.5 mol%) nanophosphor was prepared by celf-combustion sol-gel method with citric acid as fuel at 350 °C. The results of X-ray diffraction (XRD) indicated the optimum temperature to form a single-phase of nanophosphors with perovskite crystal structure was 900 °C. Surface morphology of the sample were characterized by field-emission electron microscopy (FE-SEM). In order to evaluate the quantitative analysis of available elements of the energy dispersive X-ray analysis (EDXA) connected to the SEM device was used. In order to investigate the thermoluminescence (TL) properties, at first the samples were heated at 500 °C for one hour and then irradiated with X-ray for different content of Eu impurity. The maximum intensity of thermoluminescence was obtained for the SrZrO3:xEu3+ sample with x=0.3 mol%. The Sr0.097Eu0.003ZrO3 sample was irradiated with X-ray over a period of 30 s to 5 min. As the irradiation time increases, the number of charge carriers’ increases, which results in an increase in the intensity of thermoluminescence. Linearity and reproducibility were checked for this sample, which can be a suitable option for dosimetry due to the significant stability and linearity of the thermoluminescence response. Kinetic parameters such as; activation energy, frequency factor and kinetic order were also calculated for Sr0.097Eu0.003ZrO3 dosimeter.
Hamed Alizadeh; Mohammad Mofarreh
Abstract
In heterogeneous networks integrating Radio Frequency (RF) and Visible Light Communication (VLC) modalities, the handover process is critical for maintaining connectivity and quality-of-service (QoS) in dynamic indoor environments. This paper proposes a novel deep learning assisted heuristic algorithm ...
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In heterogeneous networks integrating Radio Frequency (RF) and Visible Light Communication (VLC) modalities, the handover process is critical for maintaining connectivity and quality-of-service (QoS) in dynamic indoor environments. This paper proposes a novel deep learning assisted heuristic algorithm (DLHA) that predicts, optimizes, and executes handover decisions in an RF-VLC integrated network. By leveraging a gated recurrent unit (GRU)-based deep neural network (DNN) to forecast channel conditions and user mobility, and coupling these predictions with a heuristic decision framework, the algorithm minimizes handover latency, reduces packet loss, and balances network load. The problem is formulated as a multi-objective optimization problem with constraints on delay, energy consumption, and interference, and is further refined using principles from optimization and Markov decision processes (MDPs). Simulation results, validated on realistic indoor channel models and mobility scenarios, demonstrate that the proposed DLHA significantly outperforms conventional threshold-based methods.
Fatemeh Akbari Baseri; Alireza Jangjoo
Abstract
In this study, the attenuation and scattering behavior of photons in healthy and cancerous liver tissues was investigated using linear attenuation coefficient (μ) diagrams, differential scattering intensity, and contributions of different physical processes. The results show that the linear attenuation ...
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In this study, the attenuation and scattering behavior of photons in healthy and cancerous liver tissues was investigated using linear attenuation coefficient (μ) diagrams, differential scattering intensity, and contributions of different physical processes. The results show that the linear attenuation coefficients for both types of liver tissue are very close, with only minor differences observed in the energy range below 50 keV. At low energies, the photoelectric effect plays a dominant role in photon attenuation; however, its contribution decreases with increasing energy, and Compton scattering becomes the predominant mechanism. The scattering curves for 20 keV photons also show good agreement with the predictions of Compton theory and the Klein–Nishina formula, such that scattering intensity decreases with increasing angle, with slight differences observed between healthy and cancerous tissues at small angles. The analysis of each physical process's contribution to attenuation indicates that above 50 keV, Compton scattering accounts for more than 90% of total attenuation. In contrast, the contributions of the photoelectric and Rayleigh effects are negligible. Additionally, the ratio of the attenuation coefficient of cancerous tissue to that of healthy tissue decreases with increasing energy, reaching approximately 1.1 at 15 keV and then decreasing to 1.03 at 50 keV. These results suggest that using lower energies (approximately 15–30 keV) can enhance image contrast in liver tumor detection. Therefore, the findings of this study can serve as a basis for optimizing medical imaging protocols for the early diagnosis of liver cancer.
Karim Milanchian
Abstract
In this study, the optical behavior of a three-layer photonic structure composed of graphene sheets with hyperbolic properties and an obliquely oriented optical axis was investigated in the terahertz frequency range. The phenomena were analyzed using the effective medium approximation model and the wave ...
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In this study, the optical behavior of a three-layer photonic structure composed of graphene sheets with hyperbolic properties and an obliquely oriented optical axis was investigated in the terahertz frequency range. The phenomena were analyzed using the effective medium approximation model and the wave transfer approach. The results indicate that variations in parameters such as the graphene chemical potential, dielectric layer thicknesses, and the deviation angle of the optical axis can significantly influence the absorption and energy transmission responses for both types of incident wave polarizations. It was found that, for one of the transverse polarizations, changes in the optical axis orientation have negligible effect, whereas increasing the thickness of the first and third dielectric layers in the periodic structure reduces the bandwidth of the transmission region for both incident wave polarizations.