Asghar Ghaderi; arash boochani; Alireza Hojabri; Fatemeh Hajakbari
Abstract
Based on density functional theory calculations, the electronic, optical and thermoelectric properties of WSe2(8,0) and WSeS(8,0) nanotubes have been investigated. The WSe2(8,0) nanotube has 0.2eV energy gap, and this gap is reduced by adding a Se atom in it. The band structure shows that WSe2(8,0) nanotube ...
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Based on density functional theory calculations, the electronic, optical and thermoelectric properties of WSe2(8,0) and WSeS(8,0) nanotubes have been investigated. The WSe2(8,0) nanotube has 0.2eV energy gap, and this gap is reduced by adding a Se atom in it. The band structure shows that WSe2(8,0) nanotube is p-type semiconductor and WSeS(8,0) compound is n-type. The imaginary part of the dielectric function shows that these two structures in the infrared region have main response to the light and have small optical gaps, while the optical energy loss functions have the lowest values in this energy region. At a temperature of 200 K, the figure of merit coefficient of WSeS(8,0) nanotube is larger than WSe2(8,0) one, but at high temperatures, the power factor coefficient of WSe2(8,0) nanotube is higher, which shows that this case is suitable for power generators.
Amirmohammad Beigzadeh; MohammadReza BaSaadat
Abstract
The operation principle of calorimeters used for dosimetry of ionizing radiations is based on measuring the induced temperature difference in the adsorbent due to thermal energy deposition of the ionization radiation. In recent years, one of these methods has been the holographic optical calorimetry ...
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The operation principle of calorimeters used for dosimetry of ionizing radiations is based on measuring the induced temperature difference in the adsorbent due to thermal energy deposition of the ionization radiation. In recent years, one of these methods has been the holographic optical calorimetry by laser beams. One of the problems that affect the response accuracy of the calorimeters is the heat transfer phenomenon in the adsorbent material. This phenomenon affects the measurement accuracy of the absorbed dose. In this research, a model was developed for the post-processing of camera images of the interferometric calorimeter system with a water phantom under vertical and horizontal irradiation with electron and proton beams.
Elham Emadi; Neda Pourjafari
Abstract
Using quantum hydrodynamic (QHD) model, dust acoustic (DA) shock waves are studied in a quantum dusty plasma containing degenerate electrons, ions and negatively charged dust grains. Employing the reductive perturbation technique, a Kortweg-de Vries-Burgers (KdVB) equation is derived and solved theoretically ...
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Using quantum hydrodynamic (QHD) model, dust acoustic (DA) shock waves are studied in a quantum dusty plasma containing degenerate electrons, ions and negatively charged dust grains. Employing the reductive perturbation technique, a Kortweg-de Vries-Burgers (KdVB) equation is derived and solved theoretically and numerically. The hyperbolic tangent (tanh) method is used for theoretical solution. One of the most convenient approaches for solving the nonlinear partial differential equation in dispersive and dissipative system is the tanh method. The KdVB equation is solved numerically by fourth-order Runge – Kutta method. It is found that when dissipation dominates over dispersion, monotonic shock structure is formed, while in case of small dissipation, oscillatory shock profile is created. The influence of viscosity on DA shock waves shows that shock thickness is enhanced with the increase in viscosity. Additionally, the number and height of oscillatory shocks get increased by decreasing the viscosity. The solutions of the KdVB equation is studied in a frame moving with the phase velocity of the wave. Considering the boundary conditions, the nonlinear obtained equation is rewritten in the form of a dynamical system. In the plane, this system has two fixed points. Investigating the eigen values corresponding to these fixed points indicate that one point is always a saddle, while the other one is either a stable focus or stable node. The phase plane analysis shows that the decrease in the number of spirals show increase in dissipation.
Behnam Kazempour; Fatemeh Moslemi
Abstract
In this paper, multichannel filter tunability containing magnetized plasma and anisotropic metamaterial in 1D ternary photonic crystal is theoretically investigated and designed at the GHz frequency range. The results show that resonance modes in transmission spectrum of the proposed structure without ...
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In this paper, multichannel filter tunability containing magnetized plasma and anisotropic metamaterial in 1D ternary photonic crystal is theoretically investigated and designed at the GHz frequency range. The results show that resonance modes in transmission spectrum of the proposed structure without defining defect layer are created and the structure can act as the multichannel filter. The tunability of the transmission spectrum of the proposed structure by applying an external magnetic field is investigated and shown that channels frequency can be red or blue shifted depending on the orientation of external magnetic field. In addition, the effect of the number of periodicities, optical axis angle of anisotropic metamaterial and incident angle on the filter properties of channels for both TE and TM polarization is investigated.
noushin dadashzadeh
Abstract
Plasma technology is used in many countries in various fields such as ozone production, surface treatment, surface modification, medicine, etc. Plasma generated with microwave-like waves is a promising and interesting technology for its unique and versatile properties. These characteristics of microwave ...
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Plasma technology is used in many countries in various fields such as ozone production, surface treatment, surface modification, medicine, etc. Plasma generated with microwave-like waves is a promising and interesting technology for its unique and versatile properties. These characteristics of microwave plasma make it an alternative technology compared to traditional thermal chemical reactors, provided that its specific technical challenges are met. In this numerical study, the properties of microwave plasma with a frequency of 2.45 GHz and argon gas at atmospheric pressure were investigated. By varying the input power of the device in the range of 10 W to 20 W in magnetic mode and mode (TM), the comparative profiles of electron density, electron temperature, electric field are shown. The simulation results show the production of chemical elements in microwave plasma. High-energy electrons and electron density are considered as the main factors affecting the properties of microwave plasma.
Parisa Mahmoudi
Abstract
The field of brain mapping reveals that each region within the nervous system performs specific functions, with neurons in neural networks communicating through complex spatiotemporal patterns. Implementing these neuronal activity patterns is crucial for neuroscience to control neural activity and treat ...
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The field of brain mapping reveals that each region within the nervous system performs specific functions, with neurons in neural networks communicating through complex spatiotemporal patterns. Implementing these neuronal activity patterns is crucial for neuroscience to control neural activity and treat diseases. Researchers use these patterns for targeted neural stimulation of neurons to uncover the secrets of information processing in the brain's intricate networks. Optical neural stimulation, as a powerful tool for manipulating neurons, employs optical modulation techniques to achieve patterned light illumination on neural tissue surfaces. On the other hand, the design of implants that deliver effective, patterned light pulses to target neurons deep within brain tissue is significantly evolving. These tools enable the reconstruction of neuronal activity patterns in both two and three dimensions. This study highlights the necessity of achieving patterned light delivery techniques to neural tissue by introducing various optical stimulation techniques. Subsequently, patterned light implementation through advanced technologies, including scanning lasers, liquid crystal modulators, and digital micromirror modulators, is examined with their unique advantages and challenges. Finally, the notable advancements in fiber optic arrays, waveguides, and micro light-emitting diodes, which collectively pave the way toward more complex and less invasive neural stimulation techniques, are reviewed.