sahar rezaee - Academia.edu (original) (raw)
Papers by sahar rezaee
Microscopy research and technique, Apr 9, 2024
Modern Physics Letters B, Sep 30, 2023
International Journal of Modern Physics B
Based on density functional theory, structural, electronic, magneto-optic, and thermoelectric pro... more Based on density functional theory, structural, electronic, magneto-optic, and thermoelectric properties of RbCaN2 and RbCaO2, Heuslerene compounds have been calculated. These compounds have the ground state points with total magnetic moment of 1.0[Formula: see text][Formula: see text], which represents their ferromagnetic behavior. The RbCaN2 Heuslerene has the half-metallic nature and RbCaO2 case is a magnetic semiconductor. The Kerr angle of the RbCaN2 Heuslerene has two relatively peaks at the energies of 5.5[Formula: see text]eV to 7.0[Formula: see text]eV, but for the RbCaO2 compound, this diagram is wider in a larger energy range. Faraday angle peaks occurred at 6.2[Formula: see text]eV and 6.8[Formula: see text]eV for RbCaN2 and RbCaO2 compounds, which indicates the polarization of the light irradiated to them at these energies. It was observed that both compounds show high thermoelectric quality at temperatures higher than the room-temperature, and both compounds are suitab...
Optical and Quantum Electronics, 2020
Results in physics, Jun 1, 2018
In order to study the effect of deposition time on silver nanoparticles structure, alumina templa... more In order to study the effect of deposition time on silver nanoparticles structure, alumina templates with nano-Ag patterns were investigated. After the preparation of alumina templates by anodic oxidation method, the silver coatings were performed using ion beam sputtering method in a vacuum chamber. The effect of deposition time on the properties of Ag nanoparticle deposited on alumina templates was studied through energy dispersive Xray (EDX) spectrometer, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and Fourier transform infrared (FTIR). The results showed that time variation strongly affects the size, form, and structure of Ag nanoparticles.
Journal of Materials Science: Materials in Electronics, 2016
Results in physics, 2017
Titanium dioxide (TiO 2) films with thicknesses around 300 nm were deposited on glass substrates ... more Titanium dioxide (TiO 2) films with thicknesses around 300 nm were deposited on glass substrates by reactive radio frequency (RF) magnetron sputtering at constant RF sputtering power (200 W), high sputtering pressure and room temperature. The effects of the oxygen presence on the growth and properties of the films were investigated using mixtures of Ar and O 2 with different O 2 /(Ar + O 2) ratios (from 0.0 to 0.3) during the sample deposition. The crystalline properties and surface morphology were characterized using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The optical properties were studied by ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy, and the refractive index and the thickness of the samples were obtained using the Swanepoel method. The obtained results indicate that all the TiO 2 films grew with an anatase phase and with an improved crystallinity at O 2 /(Ar + O 2) = 0.2. However, AFM studies show that the grain size and surface roughness decrease as the O 2 /(Ar + O 2) ratio increases from 0.0 to 0.3. Moreover, a maximum refractive index was obtained for the sample prepared at O 2 /(Ar + O 2) = 0.2.
CATENA, 2021
As an important inherent condition for an eroded landform and fragile ecosystem, the erodible loe... more As an important inherent condition for an eroded landform and fragile ecosystem, the erodible loess in China's Loess Plateau is a clastic and predominantly silt-sized sediment. Understanding the pore complexity of the loess may be crucial for exploring soil functional properties and improving knowledge on hydrological dynamic processes occurring in the soil plant atmosphere continuum. Twelve undisturbed columns of four typical soil types, namely, aeolian sandy, light dark loessial, loessial, and Lou soils, were collected for the multifractal analysis of X-ray computed tomography images. The heterogeneity of soil pore distribution and the measure of porosity dispersion relative to the pore size dispersion in the loessial and Lou soils were significantly lower than those of the aeolian sandy and light dark loessial soils. The loessial soil exhibited the highest symmetry of singularity spectra and presented the lowest variability for pore arrangement. Most correlations among parameters of soil properties, multifractal characteristics, as well as soil macropore morphology and connectivity characteristics, were significant (p < 0.05 or 0.01). The multiple regression models of the theoretical saturated hydraulic conductivity and total porosity incorporated all types of the parameters, and the multifractal parameter ΔD was the dominant variable. Macropore connectivity parameters were commonly superior to the morphology ones when the links between macropore characteristics and multifractal parameters were considered. Meantime, the number of macropores acted as a crucial parameter influencing the complexity of soil pore structures. Overall, it is of great significance to integrate the soil pore complexity into the comprehensive understanding of pore function. This study also provides an effective reference for optimizing soil structures, improving the soil water holding capacity, and balancing the relationship between water and ecosystems in the Loess Plateau.
The European Physical Journal Plus, 2016
Abstract.The preparation of designed nanostructured thin films combining nano grains of different... more Abstract.The preparation of designed nanostructured thin films combining nano grains of different compositions and physical properties represents a promising avenue for the exploration of novel collective behaviors with technological potentials. Herein, nanostructured Ag-Cu thin films with different surface morphology properties were grown by magnetron sputtering varying the deposition time (4-24 min) and fixing the other deposition conditions. X-ray diffraction studies corroborated that Cu and Ag tend to appear as separated phases with nanometric sizes due to the fact that these elements are rather immiscible. The deposited Cu tended to be partially oxidized with crystal sizes of several tens of nm, whereas the deposited Ag phase displayed a poor crystallinity with an average crystal size of around 3nm. However, at deposition time of few minutes, the formation of Ag-Cu crystals with a preferable crystallization orientation along the [111] direction was detected. The surface morphology of the obtained thin films was studied by atomic force microscopy determining the surface roughness and average particle sizes of the samples. These parameters were correlated with the plasmon resonance extinction bands of the different Ag-Cu films and their electrical properties, providing a reproducible route to obtain thin films with tuned electrical resistances and optical properties.
Acta Physica Polonica A, 2019
N + ions were incorporated into nickel-coated 316 stainless steel (SS) at room temperature using ... more N + ions were incorporated into nickel-coated 316 stainless steel (SS) at room temperature using different energies (10, 20, and 50 keV) and a fluence of 5 × 10 17 N + cm −2. The microstructure, surface morphology, and corrosion inhibition of the obtained materials were investigated and compared with the properties of the untreated steel using several analytical techniques. The X-ray diffraction patterns indicated the formation of nickel nitride with the ion implantation process. The surface morphology of the samples was studied by atomic force microscopy and statistical and multifractal analytical methods. Moreover, the potentiodynamic polarization test in 3.5% NaCl solution was carried out to evaluate the corrosion properties of the samples. These studies revealed that the generalized fractal dimension, Dq, is dependent on the ion implantation energy and the symmetry of the multifractal singularity spectra, f (α), which is related to the uniformity of the sample. In this manner, the lowest value was obtained for the sample prepared with the maximum ion implantation energy. Also, the increment of the implantation energy yields to increase the corrosion resistance. The simultaneous decrease of the corrosion current density (Icorr) and the increase of the corrosion potential observed with the N + ion-implantation indicate that treated samples are more resistant to corrosion than the untreated steel, and the highest corrosion protection was observed for the maximum implantation energy (50 keV). The correlation between corrosion resistance, structural and surface morphology induced by implantation is discussed.
Materials Today Communications
Microscopy Research and Technique, Oct 12, 2022
Microscopy Research and Technique
Coatings
In the present work, Cu/Cr thin films were deposited on substrates of a different nature (Si, Gla... more In the present work, Cu/Cr thin films were deposited on substrates of a different nature (Si, Glass, Bk7, and ITO) through a thermal evaporation deposition method. Non-contact atomic force microscopy (AFM) was used to obtain 3D AFM topographical maps of the surface for the Cu/Cr samples. Various analyses were carried out to obtain crucial parameters for the characterization of the surface features. In particular, Minkowski functionals (including the normalized Minkowski volume, the Minkowski boundary, and the Minkowski connectivity) and studies of the spatial microtexture by fractal and multifractal analyses were carried out. Different roughness parameters (including arithmetical mean height, root mean square height, skewness, kurtosis, fractal dimension, Hurst coefficient, topographical entropy, and fractal lacunarity) were quantified in these analyses for the comparison of the surface morphology of the different samples. All the samples displayed non-Gaussian randomly rough surfac...
Optical and Quantum Electronics
Indian Journal of Physics
Article history: Received: 3 Dec 2018 Final Revised: 25 Feb 2019 Accepted: 26 Feb 2019 Available ... more Article history: Received: 3 Dec 2018 Final Revised: 25 Feb 2019 Accepted: 26 Feb 2019 Available online: 25 Jun 2019
Acta Physica Polonica A, 2020
In this study, we investigate the use of catalytic copper-silver-palladium substrates for the gro... more In this study, we investigate the use of catalytic copper-silver-palladium substrates for the growth of multiwalled carbon nanotubes via the thermal chemical vapor deposition. These layers are comprised of nanocrystals of Cu2O, CuO, Ag, Pd, Cu, and PdO and were grown using a DC magnetron sputtering method. Scanning electron microscopy characterizations confirmed the significant growth of carbon nanotubes on the catalytic layer. A comparison of the growth of nanotubes indicated that the thickness of the catalytic layers has a significant impact on the quality and the diameter of the carbon nanotubes. Two major peaks were seen in the Raman spectrum. The formation of graphite multiwalled nanotubes and the presence of defects in the graphene-like hexagonal disordered carbons were confirmed by the appearance of the G band (graphite band) and the D band (disorder-induced band), respectively. The ratio of the intensities of these bands, I(G)/I(D), indicated a good graphite structural quality.
Copyright © 2013 Arash Boochani et al. This is an open access article distributed under the Creat... more Copyright © 2013 Arash Boochani et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In this study, density functional theory in improved flat waves ’ framework has been used. First of all, characterization, elastic and half-metallic properties of the CrSb-ZB compound at (GGA & LDA) and GGA + U approximation are cal-culated. The elastic calculations indicate that the CrSb-ZB is a ductile material. However, the calculation of Deby tem-perature indicates that the CrSb-ZB is meta-stable. The half-metallicity character is also preserved at CrSb/InP (001) interface by GGA + U. The conduction band minimum (CBM) of CrSb in the minority spin case lies about 1.26 eV above that of GaSb, suggesting that the major spin can be injected into GaSb without being flipped to the conduction bands of the minor spin.
Microscopy research and technique, Apr 9, 2024
Modern Physics Letters B, Sep 30, 2023
International Journal of Modern Physics B
Based on density functional theory, structural, electronic, magneto-optic, and thermoelectric pro... more Based on density functional theory, structural, electronic, magneto-optic, and thermoelectric properties of RbCaN2 and RbCaO2, Heuslerene compounds have been calculated. These compounds have the ground state points with total magnetic moment of 1.0[Formula: see text][Formula: see text], which represents their ferromagnetic behavior. The RbCaN2 Heuslerene has the half-metallic nature and RbCaO2 case is a magnetic semiconductor. The Kerr angle of the RbCaN2 Heuslerene has two relatively peaks at the energies of 5.5[Formula: see text]eV to 7.0[Formula: see text]eV, but for the RbCaO2 compound, this diagram is wider in a larger energy range. Faraday angle peaks occurred at 6.2[Formula: see text]eV and 6.8[Formula: see text]eV for RbCaN2 and RbCaO2 compounds, which indicates the polarization of the light irradiated to them at these energies. It was observed that both compounds show high thermoelectric quality at temperatures higher than the room-temperature, and both compounds are suitab...
Optical and Quantum Electronics, 2020
Results in physics, Jun 1, 2018
In order to study the effect of deposition time on silver nanoparticles structure, alumina templa... more In order to study the effect of deposition time on silver nanoparticles structure, alumina templates with nano-Ag patterns were investigated. After the preparation of alumina templates by anodic oxidation method, the silver coatings were performed using ion beam sputtering method in a vacuum chamber. The effect of deposition time on the properties of Ag nanoparticle deposited on alumina templates was studied through energy dispersive Xray (EDX) spectrometer, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and Fourier transform infrared (FTIR). The results showed that time variation strongly affects the size, form, and structure of Ag nanoparticles.
Journal of Materials Science: Materials in Electronics, 2016
Results in physics, 2017
Titanium dioxide (TiO 2) films with thicknesses around 300 nm were deposited on glass substrates ... more Titanium dioxide (TiO 2) films with thicknesses around 300 nm were deposited on glass substrates by reactive radio frequency (RF) magnetron sputtering at constant RF sputtering power (200 W), high sputtering pressure and room temperature. The effects of the oxygen presence on the growth and properties of the films were investigated using mixtures of Ar and O 2 with different O 2 /(Ar + O 2) ratios (from 0.0 to 0.3) during the sample deposition. The crystalline properties and surface morphology were characterized using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The optical properties were studied by ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy, and the refractive index and the thickness of the samples were obtained using the Swanepoel method. The obtained results indicate that all the TiO 2 films grew with an anatase phase and with an improved crystallinity at O 2 /(Ar + O 2) = 0.2. However, AFM studies show that the grain size and surface roughness decrease as the O 2 /(Ar + O 2) ratio increases from 0.0 to 0.3. Moreover, a maximum refractive index was obtained for the sample prepared at O 2 /(Ar + O 2) = 0.2.
CATENA, 2021
As an important inherent condition for an eroded landform and fragile ecosystem, the erodible loe... more As an important inherent condition for an eroded landform and fragile ecosystem, the erodible loess in China's Loess Plateau is a clastic and predominantly silt-sized sediment. Understanding the pore complexity of the loess may be crucial for exploring soil functional properties and improving knowledge on hydrological dynamic processes occurring in the soil plant atmosphere continuum. Twelve undisturbed columns of four typical soil types, namely, aeolian sandy, light dark loessial, loessial, and Lou soils, were collected for the multifractal analysis of X-ray computed tomography images. The heterogeneity of soil pore distribution and the measure of porosity dispersion relative to the pore size dispersion in the loessial and Lou soils were significantly lower than those of the aeolian sandy and light dark loessial soils. The loessial soil exhibited the highest symmetry of singularity spectra and presented the lowest variability for pore arrangement. Most correlations among parameters of soil properties, multifractal characteristics, as well as soil macropore morphology and connectivity characteristics, were significant (p < 0.05 or 0.01). The multiple regression models of the theoretical saturated hydraulic conductivity and total porosity incorporated all types of the parameters, and the multifractal parameter ΔD was the dominant variable. Macropore connectivity parameters were commonly superior to the morphology ones when the links between macropore characteristics and multifractal parameters were considered. Meantime, the number of macropores acted as a crucial parameter influencing the complexity of soil pore structures. Overall, it is of great significance to integrate the soil pore complexity into the comprehensive understanding of pore function. This study also provides an effective reference for optimizing soil structures, improving the soil water holding capacity, and balancing the relationship between water and ecosystems in the Loess Plateau.
The European Physical Journal Plus, 2016
Abstract.The preparation of designed nanostructured thin films combining nano grains of different... more Abstract.The preparation of designed nanostructured thin films combining nano grains of different compositions and physical properties represents a promising avenue for the exploration of novel collective behaviors with technological potentials. Herein, nanostructured Ag-Cu thin films with different surface morphology properties were grown by magnetron sputtering varying the deposition time (4-24 min) and fixing the other deposition conditions. X-ray diffraction studies corroborated that Cu and Ag tend to appear as separated phases with nanometric sizes due to the fact that these elements are rather immiscible. The deposited Cu tended to be partially oxidized with crystal sizes of several tens of nm, whereas the deposited Ag phase displayed a poor crystallinity with an average crystal size of around 3nm. However, at deposition time of few minutes, the formation of Ag-Cu crystals with a preferable crystallization orientation along the [111] direction was detected. The surface morphology of the obtained thin films was studied by atomic force microscopy determining the surface roughness and average particle sizes of the samples. These parameters were correlated with the plasmon resonance extinction bands of the different Ag-Cu films and their electrical properties, providing a reproducible route to obtain thin films with tuned electrical resistances and optical properties.
Acta Physica Polonica A, 2019
N + ions were incorporated into nickel-coated 316 stainless steel (SS) at room temperature using ... more N + ions were incorporated into nickel-coated 316 stainless steel (SS) at room temperature using different energies (10, 20, and 50 keV) and a fluence of 5 × 10 17 N + cm −2. The microstructure, surface morphology, and corrosion inhibition of the obtained materials were investigated and compared with the properties of the untreated steel using several analytical techniques. The X-ray diffraction patterns indicated the formation of nickel nitride with the ion implantation process. The surface morphology of the samples was studied by atomic force microscopy and statistical and multifractal analytical methods. Moreover, the potentiodynamic polarization test in 3.5% NaCl solution was carried out to evaluate the corrosion properties of the samples. These studies revealed that the generalized fractal dimension, Dq, is dependent on the ion implantation energy and the symmetry of the multifractal singularity spectra, f (α), which is related to the uniformity of the sample. In this manner, the lowest value was obtained for the sample prepared with the maximum ion implantation energy. Also, the increment of the implantation energy yields to increase the corrosion resistance. The simultaneous decrease of the corrosion current density (Icorr) and the increase of the corrosion potential observed with the N + ion-implantation indicate that treated samples are more resistant to corrosion than the untreated steel, and the highest corrosion protection was observed for the maximum implantation energy (50 keV). The correlation between corrosion resistance, structural and surface morphology induced by implantation is discussed.
Materials Today Communications
Microscopy Research and Technique, Oct 12, 2022
Microscopy Research and Technique
Coatings
In the present work, Cu/Cr thin films were deposited on substrates of a different nature (Si, Gla... more In the present work, Cu/Cr thin films were deposited on substrates of a different nature (Si, Glass, Bk7, and ITO) through a thermal evaporation deposition method. Non-contact atomic force microscopy (AFM) was used to obtain 3D AFM topographical maps of the surface for the Cu/Cr samples. Various analyses were carried out to obtain crucial parameters for the characterization of the surface features. In particular, Minkowski functionals (including the normalized Minkowski volume, the Minkowski boundary, and the Minkowski connectivity) and studies of the spatial microtexture by fractal and multifractal analyses were carried out. Different roughness parameters (including arithmetical mean height, root mean square height, skewness, kurtosis, fractal dimension, Hurst coefficient, topographical entropy, and fractal lacunarity) were quantified in these analyses for the comparison of the surface morphology of the different samples. All the samples displayed non-Gaussian randomly rough surfac...
Optical and Quantum Electronics
Indian Journal of Physics
Article history: Received: 3 Dec 2018 Final Revised: 25 Feb 2019 Accepted: 26 Feb 2019 Available ... more Article history: Received: 3 Dec 2018 Final Revised: 25 Feb 2019 Accepted: 26 Feb 2019 Available online: 25 Jun 2019
Acta Physica Polonica A, 2020
In this study, we investigate the use of catalytic copper-silver-palladium substrates for the gro... more In this study, we investigate the use of catalytic copper-silver-palladium substrates for the growth of multiwalled carbon nanotubes via the thermal chemical vapor deposition. These layers are comprised of nanocrystals of Cu2O, CuO, Ag, Pd, Cu, and PdO and were grown using a DC magnetron sputtering method. Scanning electron microscopy characterizations confirmed the significant growth of carbon nanotubes on the catalytic layer. A comparison of the growth of nanotubes indicated that the thickness of the catalytic layers has a significant impact on the quality and the diameter of the carbon nanotubes. Two major peaks were seen in the Raman spectrum. The formation of graphite multiwalled nanotubes and the presence of defects in the graphene-like hexagonal disordered carbons were confirmed by the appearance of the G band (graphite band) and the D band (disorder-induced band), respectively. The ratio of the intensities of these bands, I(G)/I(D), indicated a good graphite structural quality.
Copyright © 2013 Arash Boochani et al. This is an open access article distributed under the Creat... more Copyright © 2013 Arash Boochani et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In this study, density functional theory in improved flat waves ’ framework has been used. First of all, characterization, elastic and half-metallic properties of the CrSb-ZB compound at (GGA & LDA) and GGA + U approximation are cal-culated. The elastic calculations indicate that the CrSb-ZB is a ductile material. However, the calculation of Deby tem-perature indicates that the CrSb-ZB is meta-stable. The half-metallicity character is also preserved at CrSb/InP (001) interface by GGA + U. The conduction band minimum (CBM) of CrSb in the minority spin case lies about 1.26 eV above that of GaSb, suggesting that the major spin can be injected into GaSb without being flipped to the conduction bands of the minor spin.