Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.060601
Marco Antonio García Andrade, Eliseo Martínez Espinosa, Martin Salinas-Vazquez, Jorge Ramirez cruz, William Vicente, Javier Rosas Flores
The large eddy simulation approach was used to perform a numerical simulation of a flow around a helical segmented-fin tube bundle. This work focuses on the study of turbulence and the effect of segment depth on it. The simulation was conducted in an area away from the boundaries of the tube bundle, where the flow is fully-developed, and the use of periodic boundary conditions is possible. The computer-aided design of the helical segmented-fin tube geometry is incorporated into the computational grid from the immersed boundary technique. The Reynolds stress tensor was used to analyze the anisotropic state of turbulence. This flow is characterized by an anisotropic state generated by a flow with a preferential direction. A transfer of momentum in the inter-segment space and contiguous zones was observed. This intersegment flow generates a less anisotropic state of turbulence. This study aimed to understand a possible transformation of heat transfer with marginal geometrical changes and pressure drop increases.
{"title":"The effect of segmentation depth in a helical fin tube bundle on the anisotropic turbulence state","authors":"Marco Antonio García Andrade, Eliseo Martínez Espinosa, Martin Salinas-Vazquez, Jorge Ramirez cruz, William Vicente, Javier Rosas Flores","doi":"10.31349/revmexfis.69.060601","DOIUrl":"https://doi.org/10.31349/revmexfis.69.060601","url":null,"abstract":"The large eddy simulation approach was used to perform a numerical simulation of a flow around a helical segmented-fin tube bundle. This work focuses on the study of turbulence and the effect of segment depth on it. The simulation was conducted in an area away from the boundaries of the tube bundle, where the flow is fully-developed, and the use of periodic boundary conditions is possible. The computer-aided design of the helical segmented-fin tube geometry is incorporated into the computational grid from the immersed boundary technique. The Reynolds stress tensor was used to analyze the anisotropic state of turbulence. This flow is characterized by an anisotropic state generated by a flow with a preferential direction. A transfer of momentum in the inter-segment space and contiguous zones was observed. This intersegment flow generates a less anisotropic state of turbulence. This study aimed to understand a possible transformation of heat transfer with marginal geometrical changes and pressure drop increases.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.060501
S. Azzi, F. Belkharroubi, N. Ramdani, I. S. Messaoud, W. Belkilali, L. Drici, L. Blaha, I. Ameri, Yarub Al-Douri, A. Bouhemadou
This is to investigate the structural, mechanical, electronic and optical properties of half-Heusler KZnN and KZnP compounds. The ab initio method based on density functional theory is employed. The study of structural properties has allowed us to verify the cubic structure type I that is the most stable among the three possible atomic arrangements for the two half-Heusler compounds. The mechanical stability is checked, since the calculated elastic constants obey the stability criteria of cubic. Our calculations have demonstrated that KZnN is a ductile material that is considerably stiffer than KZnP, which exhibits brittleness. The obtained results for the electronic properties with mBJ-GGA approximation reveal a semiconductor behavior with a band gap along Γ as estimated at 0.3 eV and 0.9 eV for KZnN and KZnP compounds, respectively. In addition, the optical properties have been studied by analyzing the variation of different parameters such as dielectric function, refractive index, reflectivity, absorption coefficient and conductance as a function of photon’s energy for a wide range; 0 - 40 eV. The origin of peaks in the optical spectra is determined in terms of calculated energy band structures. This work has predicted strong absorption in the ultraviolet field.
{"title":"Investigation of optoelectronic properties of half-Heusler KZnN and KZnP compounds","authors":"S. Azzi, F. Belkharroubi, N. Ramdani, I. S. Messaoud, W. Belkilali, L. Drici, L. Blaha, I. Ameri, Yarub Al-Douri, A. Bouhemadou","doi":"10.31349/revmexfis.69.060501","DOIUrl":"https://doi.org/10.31349/revmexfis.69.060501","url":null,"abstract":"This is to investigate the structural, mechanical, electronic and optical properties of half-Heusler KZnN and KZnP compounds. The ab initio method based on density functional theory is employed. The study of structural properties has allowed us to verify the cubic structure type I that is the most stable among the three possible atomic arrangements for the two half-Heusler compounds. The mechanical stability is checked, since the calculated elastic constants obey the stability criteria of cubic. Our calculations have demonstrated that KZnN is a ductile material that is considerably stiffer than KZnP, which exhibits brittleness. The obtained results for the electronic properties with mBJ-GGA approximation reveal a semiconductor behavior with a band gap along Γ as estimated at 0.3 eV and 0.9 eV for KZnN and KZnP compounds, respectively. In addition, the optical properties have been studied by analyzing the variation of different parameters such as dielectric function, refractive index, reflectivity, absorption coefficient and conductance as a function of photon’s energy for a wide range; 0 - 40 eV. The origin of peaks in the optical spectra is determined in terms of calculated energy band structures. This work has predicted strong absorption in the ultraviolet field.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135372043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.061303
Alicia Cruzado, A. Cesanelli, C. Alejandro Paola
In the present work, we analyze the different regions that are configured in a vertical plane for the visualization of the inferior mirage phenomenon. To achieve our goal, we take advantage of a methodology that we have previously developed to analytically obtain the path taken by any ray emerging from a point object, explicitly considering the atmosphere’s behavior near the surface. By means of this procedure we have reached analytical expressions, dependent on measurable temperature values, to delimit the observation regions in which it would be possible to see only objects, only images, both simultaneously, or none of them. From the expressions obtained, we study how these regions are distributed under different atmospheric conditions. The results obtained show that our methodology allow to predict the position (distance from the object and height from the ground) at which an observer should be located to observe the phenomenon, knowing the values of the air temperature at three different heights in the microlayer.
{"title":"Light refraction in the earth’s atmosphere II. Inferior mirages: regions for images and objects observation","authors":"Alicia Cruzado, A. Cesanelli, C. Alejandro Paola","doi":"10.31349/revmexfis.69.061303","DOIUrl":"https://doi.org/10.31349/revmexfis.69.061303","url":null,"abstract":"In the present work, we analyze the different regions that are configured in a vertical plane for the visualization of the inferior mirage phenomenon. To achieve our goal, we take advantage of a methodology that we have previously developed to analytically obtain the path taken by any ray emerging from a point object, explicitly considering the atmosphere’s behavior near the surface. By means of this procedure we have reached analytical expressions, dependent on measurable temperature values, to delimit the observation regions in which it would be possible to see only objects, only images, both simultaneously, or none of them. From the expressions obtained, we study how these regions are distributed under different atmospheric conditions. The results obtained show that our methodology allow to predict the position (distance from the object and height from the ground) at which an observer should be located to observe the phenomenon, knowing the values of the air temperature at three different heights in the microlayer.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aims to determine the effect of the concentration of Carbon Dots on the bandwidth of the Carbon Dots luminescence spectrum. Carbon Dots are produced by ultrasonification method and characterized using UV-Vis spectroscopy, photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), electron dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and particle size analyzer (PSA). Measurement of the bandwidth of the Carbon Dots fluorescence spectrum for various concentrations was carried out by irradiating the Carbon Dots sample using a laser with a wavelength of 405 nm and looking at the spectrum of light emitted using a Kirchoff-Bunsen spectroscope.The characterization results show that the resulting Carbon Dots have a light absorption peak at a wavelength of 303 nm, a light wave emission peak at a wavelength of 508.87 nm, the surface structure of the Carbon Dots is in the form of a porous layer, the presence of the dominance of carbon and oxygen atoms in Carbon Dots, an amorphous Carbon Dots structure is observed, and the smallest measured Carbon Dots particle size is 1.12 nm. The results show that increasing the concentration of Carbon Dots causes a tendency to increase the bandwidth of orange, green and blue light spectra emitted by the particles, and in the red color there was no significant effect of increasing the concentration of Carbon Dots on the spectrum. However, increasing the concentration of Carbon Dots actually causes a narrowing of the yellow and violet color spectra.
{"title":"Effect of carbon dots nanomaterial concentration on luminance spectral bandwidth via Kirchoff-Bunsen spectroscope","authors":"Pramudya Wahyu Pradana, None Suparno, Eka Ayu Nurbaiti, Wipsar Sunu Brams Dwandaru","doi":"10.31349/revmexfis.69.061003","DOIUrl":"https://doi.org/10.31349/revmexfis.69.061003","url":null,"abstract":"This study aims to determine the effect of the concentration of Carbon Dots on the bandwidth of the Carbon Dots luminescence spectrum. Carbon Dots are produced by ultrasonification method and characterized using UV-Vis spectroscopy, photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), electron dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and particle size analyzer (PSA). Measurement of the bandwidth of the Carbon Dots fluorescence spectrum for various concentrations was carried out by irradiating the Carbon Dots sample using a laser with a wavelength of 405 nm and looking at the spectrum of light emitted using a Kirchoff-Bunsen spectroscope.The characterization results show that the resulting Carbon Dots have a light absorption peak at a wavelength of 303 nm, a light wave emission peak at a wavelength of 508.87 nm, the surface structure of the Carbon Dots is in the form of a porous layer, the presence of the dominance of carbon and oxygen atoms in Carbon Dots, an amorphous Carbon Dots structure is observed, and the smallest measured Carbon Dots particle size is 1.12 nm. The results show that increasing the concentration of Carbon Dots causes a tendency to increase the bandwidth of orange, green and blue light spectra emitted by the particles, and in the red color there was no significant effect of increasing the concentration of Carbon Dots on the spectrum. However, increasing the concentration of Carbon Dots actually causes a narrowing of the yellow and violet color spectra.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.060401
Rachna Joshi, Nupur Verma, Man Mohan
Shannon entropy (SE) for hydrogen isoelectronic sequence is calculated through numerical simulation. Fast and accurate Numerov method is applied for the computation of the wavefunctions used for the evaluation of Shannon entropy. The reliability of this approach is verified by the excellent comparison with the available literature results. It is observed that Shannon entropy values diminish with an increment in atomic number (Z). Additionally, previously unexplored Shannon entropy behaviour for a variety of higher excited orbitals is investigated. It is found that Shannon entropy exhibits an interesting behavior of increasing and decreasing nature with principal quantum number n and orbital quantum number l, respectively. Benchmark values for Shannon information entropy are established for the ground and excited states as a signature of localization and delocalization of electron density. This will further contribute to the diagnostics of spectroscopic data and atomic system complexity.
{"title":"Shannon entropy along hydrogen isoelectronic sequence using Numerov method","authors":"Rachna Joshi, Nupur Verma, Man Mohan","doi":"10.31349/revmexfis.69.060401","DOIUrl":"https://doi.org/10.31349/revmexfis.69.060401","url":null,"abstract":"Shannon entropy (SE) for hydrogen isoelectronic sequence is calculated through numerical simulation. Fast and accurate Numerov method is applied for the computation of the wavefunctions used for the evaluation of Shannon entropy. The reliability of this approach is verified by the excellent comparison with the available literature results. It is observed that Shannon entropy values diminish with an increment in atomic number (Z). Additionally, previously unexplored Shannon entropy behaviour for a variety of higher excited orbitals is investigated. It is found that Shannon entropy exhibits an interesting behavior of increasing and decreasing nature with principal quantum number n and orbital quantum number l, respectively. Benchmark values for Shannon information entropy are established for the ground and excited states as a signature of localization and delocalization of electron density. This will further contribute to the diagnostics of spectroscopic data and atomic system complexity.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.060802
Abdelmadjid Maireche
The deformed Klein-Gordonequation has been solved in three-dimensional extended relativistic quantum mechanics (3D-ERQM) symmetries for the improved modified Yukawa-Kratzer potential (IMYKP) model under the influence of the deformation space-space symmetries. The new relativistic energy eigenvalues were calculated using the parametric Bopp’s shift method and standard perturbation theory in addition to the approximation scheme suggested by Greene and Aldrich for the inverse square terms. The new relativistic energy eigenvalues of (LiH, HCl, CO and H2) molecules under the IMYKP model it was shown to be sensitive to the atomic quantum numbers (j, l, s, m), mixed potential depths (V0, De, re), the screening parameter’s inverse α and noncommutativity parameters (Θ,τ ,χ). In addition, we analyzed the nonrelativistic energy values by applying the well-known transmission rules known in the literature. In addition, we studied many special cases useful to researchers in the framework of the new extended symmetries, such as the improved modified Kratzer potential, the improved generalized Kratzer potential, the improved Kratzer potential, the improved modified Kratzer plus screened Coulomb potential, the improved Hellmann potential, the improved Yukawa potential, and improved inversely square Yukawa potential. We noticed that these particular results are identical to our previous work and other known works in the literature. The study is further extended to calculate the mass spectra of mesons of charmonium (cc) and bottomonium (bb) within the framework of the IMYKP model in three-dimensional extended non-relativistic quantum mechanics (3D-ENRQM) symmetries.
{"title":"New Eigensolution of the Klein--Gordon and Shrödinger equations for improved modified Yukawa-Kratzer potential and its applications using Boop's Shift method and standard perturbation theory in the 3D-ERQM and 3D-ENRQM symmetries","authors":"Abdelmadjid Maireche","doi":"10.31349/revmexfis.69.060802","DOIUrl":"https://doi.org/10.31349/revmexfis.69.060802","url":null,"abstract":"The deformed Klein-Gordonequation has been solved in three-dimensional extended relativistic quantum mechanics (3D-ERQM) symmetries for the improved modified Yukawa-Kratzer potential (IMYKP) model under the influence of the deformation space-space symmetries. The new relativistic energy eigenvalues were calculated using the parametric Bopp’s shift method and standard perturbation theory in addition to the approximation scheme suggested by Greene and Aldrich for the inverse square terms. The new relativistic energy eigenvalues of (LiH, HCl, CO and H2) molecules under the IMYKP model it was shown to be sensitive to the atomic quantum numbers (j, l, s, m), mixed potential depths (V0, De, re), the screening parameter’s inverse α and noncommutativity parameters (Θ,τ ,χ). In addition, we analyzed the nonrelativistic energy values by applying the well-known transmission rules known in the literature. In addition, we studied many special cases useful to researchers in the framework of the new extended symmetries, such as the improved modified Kratzer potential, the improved generalized Kratzer potential, the improved Kratzer potential, the improved modified Kratzer plus screened Coulomb potential, the improved Hellmann potential, the improved Yukawa potential, and improved inversely square Yukawa potential. We noticed that these particular results are identical to our previous work and other known works in the literature. The study is further extended to calculate the mass spectra of mesons of charmonium (cc) and bottomonium (bb) within the framework of the IMYKP model in three-dimensional extended non-relativistic quantum mechanics (3D-ENRQM) symmetries.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135373387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.061202
Rolando Martínez Ramírez, Óscar Iván Valdés Martínez, Eric Vázquez Jáuregui
The radioactivity concentration for shrimp and sea bass retrieved from the Mexican Pacific Ocean and the Gulf of Mexico is reported in this work. The activity of 40K and 208Tl was determined with gamma spectroscopy using a High Purity Germanium detector. Overall, the radioactivity concentration of samples from the Mexican Pacific Ocean is higher than from the Gulf of Mexico. The 40K concentration measured for shrimp is 575 ± 14 Bq/kg (Pacific) and 443 ± 10 Bq/kg (Gulf), while the activity for sea bass is 753 ± 18 Bq/kg (Pacific) and 502 ± 14 Bq/kg (Gulf). Similarly, the measured concentration of 208Tl for shrimp and sea bass is 0.75 ± 0.03 and 1.09 ± 0.05 Bq/kg (Pacific), respectively, and 0.51 ± 0.02 and 0.85 ± 0.04 Bq/kg (Gulf), respectively. No other natural radionuclides or radiation contaminants were observed with significant activity. This is the first comparison of radioactivity concentration in fish and shellfish between the two main Mexican marine ecosystems.
{"title":"Natural radioactivity concentration measurements in shrimp and sea bass samples from the Mexican Pacific Ocean and the Gulf of Mexico","authors":"Rolando Martínez Ramírez, Óscar Iván Valdés Martínez, Eric Vázquez Jáuregui","doi":"10.31349/revmexfis.69.061202","DOIUrl":"https://doi.org/10.31349/revmexfis.69.061202","url":null,"abstract":"The radioactivity concentration for shrimp and sea bass retrieved from the Mexican Pacific Ocean and the Gulf of Mexico is reported in this work. The activity of 40K and 208Tl was determined with gamma spectroscopy using a High Purity Germanium detector. Overall, the radioactivity concentration of samples from the Mexican Pacific Ocean is higher than from the Gulf of Mexico. The 40K concentration measured for shrimp is 575 ± 14 Bq/kg (Pacific) and 443 ± 10 Bq/kg (Gulf), while the activity for sea bass is 753 ± 18 Bq/kg (Pacific) and 502 ± 14 Bq/kg (Gulf). Similarly, the measured concentration of 208Tl for shrimp and sea bass is 0.75 ± 0.03 and 1.09 ± 0.05 Bq/kg (Pacific), respectively, and 0.51 ± 0.02 and 0.85 ± 0.04 Bq/kg (Gulf), respectively. No other natural radionuclides or radiation contaminants were observed with significant activity. This is the first comparison of radioactivity concentration in fish and shellfish between the two main Mexican marine ecosystems.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.31349/revmexfis.69.061101
Arón Hernández Trinidad, Teodoro Córdova Fraga, Luis Carlos Padierna García, José Luis López Hernández, Blanca Olivia Murillo Ortiz, Rafael Guzman-Cabrera
In the present research, a supervised learning classification methodology is proposed to identify post-COVID conditions. Image processing and deep learning methods were employed to analyze a data set provided by the High Specialty Medical Unit No.1 of the Mexican Institute of Social Security (T1-IMSS) of Leon, Guanajuato, Mexico, of Mexican patients infected with COVID-19. The dataset is classified into post-COVID findings and no post-COVID findings. A deep neural network of 50 hidden layers is used to extract regions of interest, with properties that can potentially be related to computer-aided medical diagnosis. Different patterns were found in the post-COVID computed tomography scans: pulmonary fibrosis, ground glass pattern, etc. The efficiency of the proposed method was 97% precision using the cross-validation classification scenario. This result allows to provide an auxiliary tool in medical diagnosis, through computer-aided diagnosis. This model provides an automatic and objective estimation of post-COVID conditions of Mexican patients, facilitating the expert interpretation during the COVID-19 pandemic.
{"title":"Automatic image processing to identify post-COVID conditions by using deep learning","authors":"Arón Hernández Trinidad, Teodoro Córdova Fraga, Luis Carlos Padierna García, José Luis López Hernández, Blanca Olivia Murillo Ortiz, Rafael Guzman-Cabrera","doi":"10.31349/revmexfis.69.061101","DOIUrl":"https://doi.org/10.31349/revmexfis.69.061101","url":null,"abstract":"In the present research, a supervised learning classification methodology is proposed to identify post-COVID conditions. Image processing and deep learning methods were employed to analyze a data set provided by the High Specialty Medical Unit No.1 of the Mexican Institute of Social Security (T1-IMSS) of Leon, Guanajuato, Mexico, of Mexican patients infected with COVID-19. The dataset is classified into post-COVID findings and no post-COVID findings. A deep neural network of 50 hidden layers is used to extract regions of interest, with properties that can potentially be related to computer-aided medical diagnosis. Different patterns were found in the post-COVID computed tomography scans: pulmonary fibrosis, ground glass pattern, etc. The efficiency of the proposed method was 97% precision using the cross-validation classification scenario. This result allows to provide an auxiliary tool in medical diagnosis, through computer-aided diagnosis. This model provides an automatic and objective estimation of post-COVID conditions of Mexican patients, facilitating the expert interpretation during the COVID-19 pandemic.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135373388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nano optical crescent patch antenna for Terahertz applications using Graphene is designed in this paper. The antenna is designed at 7.28 THZ with several substrates material as PTFE (²r = 2.1), polymide (²r = 3.5), RO3003 (²r = 3), RO4003 (²r = 3.4) and Arlon AD (²r = 2.5). Graphene is the material patch used with different properties such as chemical potential µc = 0.2 eV, relaxation time τ = 1 ps and thickness of 60 nm to achieve a high gain and bandwidth. We obtained a very good performance of crescent antenna at 7.28 THZ with −37.962 dB, 7.124 dBi, 1.767 THZ of return loss, gain and bandwidth respectively which is very satisfactory for terahertz transmission between [0.1-10] THZ.
{"title":"Optical nano patch antenna for terahertz applications with graphene","authors":"Bouchra Moulfi, Souheyla Ferouani, Djalal Ziani Kerarti","doi":"10.31349/revmexfis.69.061302","DOIUrl":"https://doi.org/10.31349/revmexfis.69.061302","url":null,"abstract":"Nano optical crescent patch antenna for Terahertz applications using Graphene is designed in this paper. The antenna is designed at 7.28 THZ with several substrates material as PTFE (²r = 2.1), polymide (²r = 3.5), RO3003 (²r = 3), RO4003 (²r = 3.4) and Arlon AD (²r = 2.5). Graphene is the material patch used with different properties such as chemical potential µc = 0.2 eV, relaxation time τ = 1 ps and thickness of 60 nm to achieve a high gain and bandwidth. We obtained a very good performance of crescent antenna at 7.28 THZ with −37.962 dB, 7.124 dBi, 1.767 THZ of return loss, gain and bandwidth respectively which is very satisfactory for terahertz transmission between [0.1-10] THZ.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135373092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The structural, electronic, optical, and thermoelectric properties of the niobium new halide double perovskites Cs2GeNbX6 (X = Cl, Br, I) were investigated using a density functional theory method. The generalized gradient approximation (GGA) method is used to project the exchange-correlation potential. The tolerance factor and optimizing total energy define the structure's stability. The magnetic moments of our compounds are high, more than 3μB. The compounds have direct narrow band gaps of 0.69, 0.46, and 0.26 eV, respectively, for Cs2GeNbCl6, Cs2GeNbBr6, and Cs2GeNbI6, as determined by band structure calculations. This is ideal for investigating these compounds for use in solar cells. In addition, the investigated compounds were investigated in terms of optical absorption, refractive index, and dielectric constants for energy range 0–12 eV, ensuring absorption in infrared, visible, and ultraviolet regions. This was done in order to study optical characteristics. The investigated compounds are excellent candidates for harvest solar cell applications due to their maximum visible absorption. They are also good candidates for thermoelectric applications due to their Seebeck coefficient, lattice thermal, electric conductivities and figure of merit (ZT) addressed by Boltzmann theory.
{"title":"Evolution of electronic bandgap by anion variation to explore niobium new halide double perovskites Cs2GeNbX6 (X = Cl, Br, I) for solar cells and thermoelectric applications: first principles analysis","authors":"Abbes Labdelli, Fatima Bendahma, Mohamed Mana, Noureddine Benderdouche","doi":"10.31349/revmexfis.69.061001","DOIUrl":"https://doi.org/10.31349/revmexfis.69.061001","url":null,"abstract":"The structural, electronic, optical, and thermoelectric properties of the niobium new halide double perovskites Cs2GeNbX6 (X = Cl, Br, I) were investigated using a density functional theory method. The generalized gradient approximation (GGA) method is used to project the exchange-correlation potential. The tolerance factor and optimizing total energy define the structure's stability. The magnetic moments of our compounds are high, more than 3μB. The compounds have direct narrow band gaps of 0.69, 0.46, and 0.26 eV, respectively, for Cs2GeNbCl6, Cs2GeNbBr6, and Cs2GeNbI6, as determined by band structure calculations. This is ideal for investigating these compounds for use in solar cells. In addition, the investigated compounds were investigated in terms of optical absorption, refractive index, and dielectric constants for energy range 0–12 eV, ensuring absorption in infrared, visible, and ultraviolet regions. This was done in order to study optical characteristics. The investigated compounds are excellent candidates for harvest solar cell applications due to their maximum visible absorption. They are also good candidates for thermoelectric applications due to their Seebeck coefficient, lattice thermal, electric conductivities and figure of merit (ZT) addressed by Boltzmann theory.","PeriodicalId":21538,"journal":{"name":"Revista Mexicana De Fisica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135373372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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