Pub Date : 2024-12-17DOI: 10.1016/j.jqsrt.2024.109320
David Santalices, Juan Meléndez, Susana Briz
Periodic fluctuations in the incoming spectrum to a Fourier-transform infrared (FTIR) spectrometer often result in spectral artifacts that can compromise quantitative measurements. This study presents a novel method that relaxes the conventional assumption of uniform fluctuations across all frequencies, by modeling the radiance fluctuations with a Fourier series expansion with wavenumber-dependent coefficients. By limiting the incoming spectral bandwidth with an interference filter, it is possible to retrieve the artifact-free average spectrum and to obtain the temporal evolution of the incident radiance. Experimental validation was conducted with transmittance measurements on a methane gas sample whose column density was periodically modulated. This method expands FTIR capabilities, particularly for applications involving fluctuating gases, and enhances the potential for time-resolved analysis in complex environments.
{"title":"Analysis of periodic temporal changes in the spectral signature of IR sources by modeling of spectral artifacts in FTIR systems","authors":"David Santalices, Juan Meléndez, Susana Briz","doi":"10.1016/j.jqsrt.2024.109320","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109320","url":null,"abstract":"Periodic fluctuations in the incoming spectrum to a Fourier-transform infrared (FTIR) spectrometer often result in spectral artifacts that can compromise quantitative measurements. This study presents a novel method that relaxes the conventional assumption of uniform fluctuations across all frequencies, by modeling the radiance fluctuations with a Fourier series expansion with wavenumber-dependent coefficients. By limiting the incoming spectral bandwidth with an interference filter, it is possible to retrieve the artifact-free average spectrum and to obtain the temporal evolution of the incident radiance. Experimental validation was conducted with transmittance measurements on a methane gas sample whose column density was periodically modulated. This method expands FTIR capabilities, particularly for applications involving fluctuating gases, and enhances the potential for time-resolved analysis in complex environments.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-15DOI: 10.1016/j.jqsrt.2024.109318
Netai Das, Arijit Ghoshal, Yew Kam Ho
The existence and the behaviour of the resonance states in the scattering of electrons from the hydrogen atoms under semi-classical plasma environments are investigated. The organized effect of the plasma charged particles is modelled by a pseudopotential which takes care of the quantum mechanical effect of diffraction at short distances as well as the collective effect of the plasma particles by means of two adjustable parameters, namely the de Broglie wavelength λ and the screening parameter κ. An extensive square-integrable basis set is employed within the framework of the stabilization method to determine the S-wave resonance states in the e-H system. In particular, the emergence of three S-wave singlet resonance states is identified by noting the stabilized energy levels, whereas the energy and the width of those states are computed from the fitting of the density of the states with the Lorentzian form. The results for the plasma-free case are in good agreement with the established results in the literature. A comprehensive study is made on the changes in the energy and width of the resonance states as a result of variation in λ at a given κ.
{"title":"Electron scattering from hydrogen atom in dense semi-classical hydrogen plasma: S-wave resonance states","authors":"Netai Das, Arijit Ghoshal, Yew Kam Ho","doi":"10.1016/j.jqsrt.2024.109318","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109318","url":null,"abstract":"The existence and the behaviour of the resonance states in the scattering of electrons from the hydrogen atoms under semi-classical plasma environments are investigated. The organized effect of the plasma charged particles is modelled by a pseudopotential which takes care of the quantum mechanical effect of diffraction at short distances as well as the collective effect of the plasma particles by means of two adjustable parameters, namely the de Broglie wavelength <mml:math altimg=\"si1.svg\" display=\"inline\"><mml:mi>λ</mml:mi></mml:math> and the screening parameter <mml:math altimg=\"si2.svg\" display=\"inline\"><mml:mi>κ</mml:mi></mml:math>. An extensive square-integrable basis set is employed within the framework of the stabilization method to determine the S-wave resonance states in the e-H system. In particular, the emergence of three S-wave singlet resonance states is identified by noting the stabilized energy levels, whereas the energy and the width of those states are computed from the fitting of the density of the states with the Lorentzian form. The results for the plasma-free case are in good agreement with the established results in the literature. A comprehensive study is made on the changes in the energy and width of the resonance states as a result of variation in <mml:math altimg=\"si1.svg\" display=\"inline\"><mml:mi>λ</mml:mi></mml:math> at a given <mml:math altimg=\"si2.svg\" display=\"inline\"><mml:mi>κ</mml:mi></mml:math>.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"92 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-14DOI: 10.1016/j.jqsrt.2024.109323
Olga Shefer
For set of crystals with and without taking into account nonsphericity and preferential orientation, there are presented the calculation results that generalize the features of the spectral behavior of the extinction efficiency factor of radiant energy. The influence of various physico-chemical characteristics of scatterers on extinction is demonstrated. The scheme is proposed for comparative analysis of the extinction coefficient of visible and infrared radiation for different components of ice cloud. Considering a medium containing methane and large ice plates, there is demonstrated the scheme to estimate cooperative and separated contributions of dispersed and gas components to the total extinction by the mixture.
{"title":"Separated and cooperative influence of components of ice cloud on total extinction of optical radiation","authors":"Olga Shefer","doi":"10.1016/j.jqsrt.2024.109323","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109323","url":null,"abstract":"For set of crystals with and without taking into account nonsphericity and preferential orientation, there are presented the calculation results that generalize the features of the spectral behavior of the extinction efficiency factor of radiant energy. The influence of various physico-chemical characteristics of scatterers on extinction is demonstrated. The scheme is proposed for comparative analysis of the extinction coefficient of visible and infrared radiation for different components of ice cloud. Considering a medium containing methane and large ice plates, there is demonstrated the scheme to estimate cooperative and separated contributions of dispersed and gas components to the total extinction by the mixture.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"31 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-10DOI: 10.1016/j.jqsrt.2024.109321
Adam Pastorek, Peter Bernath
We present a comprehensive data analysis of coincident solar occultation data captured by the ACE satellite, alongside the atmospheric river database derived from MERRA-2 reanalysis through the ARTMIP (Atmospheric River Tracking Method Intercomparison Project) initiative. Our investigation, comparing an atmospheric river catalogue by Guan and Waliser (2015) with experimental ACE data, reveals significant differences in altitude-dependent volume-mixing ratios (VMRs) of several molecules (particularly H2O, HNO3, and O3). These differences are observed in pairs of ACE observations that are closely matched in time and location, with one point falling within an identified atmospheric river and the other outside. Additionally, we demonstrate that these differences in VMR profiles are not attributable to random atmospheric turbulence. This is achieved by contrasting our findings with a randomized set of paired ACE observations, where both data points are situated outside of atmospheric rivers. The obtained results corroborate atmospheric mixing between the troposphere and stratosphere during the passage of an atmospheric river through a specific location. Our findings demonstrate the utility of ACE satellite data in observing atmospheric phenomena associated with atmospheric rivers.
{"title":"Comparison of atmospheric river-related phenomena with ACE satellite data","authors":"Adam Pastorek, Peter Bernath","doi":"10.1016/j.jqsrt.2024.109321","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109321","url":null,"abstract":"We present a comprehensive data analysis of coincident solar occultation data captured by the ACE satellite, alongside the atmospheric river database derived from MERRA-2 reanalysis through the ARTMIP (Atmospheric River Tracking Method Intercomparison Project) initiative. Our investigation, comparing an atmospheric river catalogue by Guan and Waliser (2015) with experimental ACE data, reveals significant differences in altitude-dependent volume-mixing ratios (VMRs) of several molecules (particularly H<ce:inf loc=\"post\">2</ce:inf>O, HNO<ce:inf loc=\"post\">3</ce:inf>, and O<ce:inf loc=\"post\">3</ce:inf>). These differences are observed in pairs of ACE observations that are closely matched in time and location, with one point falling within an identified atmospheric river and the other outside. Additionally, we demonstrate that these differences in VMR profiles are not attributable to random atmospheric turbulence. This is achieved by contrasting our findings with a randomized set of paired ACE observations, where both data points are situated outside of atmospheric rivers. The obtained results corroborate atmospheric mixing between the troposphere and stratosphere during the passage of an atmospheric river through a specific location. Our findings demonstrate the utility of ACE satellite data in observing atmospheric phenomena associated with atmospheric rivers.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"61 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-10DOI: 10.1016/j.jqsrt.2024.109311
Vadim A. Markel, Manabu Machida, John C. Schotland
We consider the collision expansion of the Green’s function of the radiative transport equation (RTE) in an infinite medium. Analytical expressions in terms of quadratures of the most simple form are given for all orders of the expansion. Singularities of the Green’s function are considered in detail. While it is well known that the zeroth and first terms in the expansion are singular (and proportional to delta functions), we show that the second order term contains a logarithmic singularity. All higher-order terms are regular. We further establish a relation between the Green’s function and the signal measured by a collimated detector. In the presence of singularities, this relation is not always obvious and, at second order, it cannot be stated in a form that is independent of the acceptance angle of the detector. We also consider the density and energy current. Theoretical results are supported by Monte-Carlo simulations.
{"title":"Collision expansion for the radiative transport equation: Analytical results and numerical simulations","authors":"Vadim A. Markel, Manabu Machida, John C. Schotland","doi":"10.1016/j.jqsrt.2024.109311","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109311","url":null,"abstract":"We consider the collision expansion of the Green’s function of the radiative transport equation (RTE) in an infinite medium. Analytical expressions in terms of quadratures of the most simple form are given for all orders of the expansion. Singularities of the Green’s function are considered in detail. While it is well known that the zeroth and first terms in the expansion are singular (and proportional to delta functions), we show that the second order term contains a logarithmic singularity. All higher-order terms are regular. We further establish a relation between the Green’s function and the signal measured by a collimated detector. In the presence of singularities, this relation is not always obvious and, at second order, it cannot be stated in a form that is independent of the acceptance angle of the detector. We also consider the density and energy current. Theoretical results are supported by Monte-Carlo simulations.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"28 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Empirical and semi-empirical models of the continua absorption are still ubiquitously used in atmospheric science and applications despite almost a hundred-years-long persistent theoretical and experimental investigation of the continuum' nature. Based on the empirical knowledge accumulated to-date about the water vapor continuum we propose a physically sound continuum model for practical applications in the subterahertz frequency range (0-1 THz). Our model interpret the water vapor continuum in terms of a combination of various contributions owed to bimolecular absorption. The self-continuum component is presented in the model as a sum of the contributions from absorption by bound and quasibound dimers, which are evaluated with the help of the water vapor second virial coefficient and existing ab initio simulation of the water dimer absorption. The contribution from the far wings of the water monomer resonant lines is taken into account by virtue of a simple analytical function approximating available empirical data. The foreign-continuum component of absorption is taken in a conventional empirical form. The values of its numerical coefficients are updated to achieve better agreement with results of laboratory measurements in the sub-THz range. We demonstrate that our new model is in good agreement with modern versions of atmospheric propagation models. However, the atmospheric brightness temperature calculated using our new model systematically deviates from the results obtained with its empirical version. The deviation amounts up to several Kelvins in the microwindows between resonant water lines.
{"title":"Atmospheric water vapor continuum model for the sub-THz range","authors":"M.Yu. Tretyakov, T.A. Galanina, A.O. Koroleva, D.S. Makarov, D.N. Chistikov, A.A. Finenko, A.A. Vigasin","doi":"10.1016/j.jqsrt.2024.109319","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109319","url":null,"abstract":"Empirical and semi-empirical models of the continua absorption are still ubiquitously used in atmospheric science and applications despite almost a hundred-years-long persistent theoretical and experimental investigation of the continuum' nature. Based on the empirical knowledge accumulated to-date about the water vapor continuum we propose a physically sound continuum model for practical applications in the subterahertz frequency range (0-1 THz). Our model interpret the water vapor continuum in terms of a combination of various contributions owed to bimolecular absorption. The self-continuum component is presented in the model as a sum of the contributions from absorption by bound and quasibound dimers, which are evaluated with the help of the water vapor second virial coefficient and existing <ce:italic>ab initio</ce:italic> simulation of the water dimer absorption. The contribution from the far wings of the water monomer resonant lines is taken into account by virtue of a simple analytical function approximating available empirical data. The foreign-continuum component of absorption is taken in a conventional empirical form. The values of its numerical coefficients are updated to achieve better agreement with results of laboratory measurements in the sub-THz range. We demonstrate that our new model is in good agreement with modern versions of atmospheric propagation models. However, the atmospheric brightness temperature calculated using our new model systematically deviates from the results obtained with its empirical version. The deviation amounts up to several Kelvins in the microwindows between resonant water lines.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"93 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-07DOI: 10.1016/j.jqsrt.2024.109307
Charles S. Callahan, Sean M. Bresler, Sean C. Coburn, David A. Long, Gregory B. Rieker
Interpreting measured absorption spectroscopy data can require repeated simulations of the expected absorption spectrum to fit the data. In cases of high temperature or broadband spectra, the computational load of the spectral analysis can be expensive due to the large number of individual absorption transitions that contribute to each simulation. We present a Graphics Processing Unit (GPU) Accelerated Absorption Simulator (GAAS) – a fast, hardware-accelerated, line-by-line absorption simulation software for generating absorption spectra based on Voigt and Hartmann-Tran lineshape profiles. We show that GAAS produces the same output spectra as the high-resolution transmission molecular absorption database (HITRAN) Application Programming Interface (HAPI) to within 32-bits of numerical precision for spectra based on both Voigt and Hartmann-Tran profiles. We also measure the performance increase compared to HAPI and demonstrate that GAAS can reduce simulation time by up to 115x for spectra containing many (several thousand or more) absorption transitions. The software is provided as an open-source python library which is built around an OpenCL implementation of the Voigt and Hartmann-Tran lineshape functions. GAAS can be run on a variety of GPU hardware including integrated GPUs on most computers and high-performance external GPUs. It is installed as a standalone Python library, making it accessible and easy to use for many applications. GAAS will enable researchers to more efficiently analyze complex spectra, especially using advanced lineshapes, to ultimately increase the accuracy of complex spectroscopic measurements.
{"title":"GAAS: GPU accelerated absorption simulator","authors":"Charles S. Callahan, Sean M. Bresler, Sean C. Coburn, David A. Long, Gregory B. Rieker","doi":"10.1016/j.jqsrt.2024.109307","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109307","url":null,"abstract":"Interpreting measured absorption spectroscopy data can require repeated simulations of the expected absorption spectrum to fit the data. In cases of high temperature or broadband spectra, the computational load of the spectral analysis can be expensive due to the large number of individual absorption transitions that contribute to each simulation. We present a Graphics Processing Unit (GPU) Accelerated Absorption Simulator (GAAS) – a fast, hardware-accelerated, line-by-line absorption simulation software for generating absorption spectra based on Voigt and Hartmann-Tran lineshape profiles. We show that GAAS produces the same output spectra as the <ce:italic>hi</ce:italic>gh-resolution <ce:italic>trans</ce:italic>mission molecular absorption database (HITRAN) Application Programming Interface (HAPI) to within 32-bits of numerical precision for spectra based on both Voigt and Hartmann-Tran profiles. We also measure the performance increase compared to HAPI and demonstrate that GAAS can reduce simulation time by up to 115x for spectra containing many (several thousand or more) absorption transitions. The software is provided as an open-source python library which is built around an OpenCL implementation of the Voigt and Hartmann-Tran lineshape functions. GAAS can be run on a variety of GPU hardware including integrated GPUs on most computers and high-performance external GPUs. It is installed as a standalone Python library, making it accessible and easy to use for many applications. GAAS will enable researchers to more efficiently analyze complex spectra, especially using advanced lineshapes, to ultimately increase the accuracy of complex spectroscopic measurements.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"134 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-06DOI: 10.1016/j.jqsrt.2024.109312
Murat Kaan Özcan, Muhsin Caner Gökçe, Yahya Baykal
The study examines the average transmittance of Gaussian beams passing through various biological tissues, taking into account the impact of turbulence, absorption, and scattering. The extended Huygens-Fresnel technique, which utilizes the power spectrum of turbulent biological tissues, is applied to determine the optical intensity at the observation point. Additionally, there are tabulated absorption and scattering coefficients available for the application of the Beer-Lambert law, facilitating the calculation of optical light attenuation in biological tissues. Examining the impact of turbulence, as well as absorption and scattering-induced attenuation on the Gaussian beam's propagation, the changes in transmittance are documented across different tissue parameters.
{"title":"Transmittance of Gaussian beams in biological tissues","authors":"Murat Kaan Özcan, Muhsin Caner Gökçe, Yahya Baykal","doi":"10.1016/j.jqsrt.2024.109312","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109312","url":null,"abstract":"The study examines the average transmittance of Gaussian beams passing through various biological tissues, taking into account the impact of turbulence, absorption, and scattering. The extended Huygens-Fresnel technique, which utilizes the power spectrum of turbulent biological tissues, is applied to determine the optical intensity at the observation point. Additionally, there are tabulated absorption and scattering coefficients available for the application of the Beer-Lambert law, facilitating the calculation of optical light attenuation in biological tissues. Examining the impact of turbulence, as well as absorption and scattering-induced attenuation on the Gaussian beam's propagation, the changes in transmittance are documented across different tissue parameters.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"49 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-06DOI: 10.1016/j.jqsrt.2024.109315
Alexis Abad, Alexandre Poux, Marc Brunel
A convolutional neural network (CNN) has been trained to reconstruct the two-dimensional (2D) shape of rough particles from their interferometric defocused images. The experimental set-up uses a digital micro-mirror device (DMD). The particles programmed on the DMD can have different morphologies: stick, cross, dendrite, L, T and Y. Sticks, crosses and dendrites are centrosymmetric, while l-, T-, and Y-shaped particles are non-centrosymmetric. For each family of particle, the training of the CNN has been performed for particle's sizes that cover a decade from hundreds of micrometers to millimeters, and for an arbitrary 3D-orientation of the particle. Accurate reconstructions and particle sizing can be done. Using three orthogonal views of the same particle, a three-dimensional (3D) reconstruction can be further done to estimate the 3D-morphology of the particle.
{"title":"Convolutional neural network for 2D-reconstructions of rough particles from their experimental speckle images in interferometric particle imaging","authors":"Alexis Abad, Alexandre Poux, Marc Brunel","doi":"10.1016/j.jqsrt.2024.109315","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109315","url":null,"abstract":"A convolutional neural network (CNN) has been trained to reconstruct the two-dimensional (2D) shape of rough particles from their interferometric defocused images. The experimental set-up uses a digital micro-mirror device (DMD). The particles programmed on the DMD can have different morphologies: stick, cross, dendrite, L, T and Y. Sticks, crosses and dendrites are centrosymmetric, while <ce:small-caps>l</ce:small-caps>-, T-, and Y-shaped particles are non-centrosymmetric. For each family of particle, the training of the CNN has been performed for particle's sizes that cover a decade from hundreds of micrometers to millimeters, and for an arbitrary 3D-orientation of the particle. Accurate reconstructions and particle sizing can be done. Using three orthogonal views of the same particle, a three-dimensional (3D) reconstruction can be further done to estimate the 3D-morphology of the particle.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"279 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-12-05DOI: 10.1016/j.jqsrt.2024.109314
Zhengwei Tao, Jun Qiu
The optical constants of fiber materials are of great value in the study of the mechanism and application of radiation regulation, but the conventional methods for obtaining the optical constants of fiber materials suffer from a series of problems such as compositional differences, chemical residues, and microstructural damages, which make it difficult to obtain the optical constants of the fiber materials and make the final results of the measurements doubtful. In this work, a new intelligent inversion method is developed, based on the first-principles calculations of electromagnetic scattering using Finite Difference Time Domain method and particle swarm optimization algorithm (FDTD-PSO), to obtain the optical constants of fibers through the measurement of the scattered radiation properties of fiber materials and the characterization of their surface microstructures. The feasibility and accuracy of the method are demonstrated by theoretical numerical calculation simulations of different kinds of fibers, and the scale effect and error are analyzed from three aspects, namely, scale parameters, roughness and incident light angle direction. The results show that the dimensions, roughness and incident wavelength of the fiber material are in the sub-wavelength scale interval, which requires high model accuracy and gives the appropriate inversion range interval. Finally, the method is experimentally validated by using the natural silk fibers. This work constructs a complete set of theoretical models and experimental methods to accurately obtain the optical constants of actual fiber materials, which provides a new direction for obtaining the optical constants of fiber materials and a numerical basis for the study of the radiation modulation mechanism of fiber materials.
{"title":"Inversion of optical constants of natural silk fibers based on FDTD-PSO and scattering experiments","authors":"Zhengwei Tao, Jun Qiu","doi":"10.1016/j.jqsrt.2024.109314","DOIUrl":"https://doi.org/10.1016/j.jqsrt.2024.109314","url":null,"abstract":"The optical constants of fiber materials are of great value in the study of the mechanism and application of radiation regulation, but the conventional methods for obtaining the optical constants of fiber materials suffer from a series of problems such as compositional differences, chemical residues, and microstructural damages, which make it difficult to obtain the optical constants of the fiber materials and make the final results of the measurements doubtful. In this work, a new intelligent inversion method is developed, based on the first-principles calculations of electromagnetic scattering using Finite Difference Time Domain method and particle swarm optimization algorithm (FDTD-PSO), to obtain the optical constants of fibers through the measurement of the scattered radiation properties of fiber materials and the characterization of their surface microstructures. The feasibility and accuracy of the method are demonstrated by theoretical numerical calculation simulations of different kinds of fibers, and the scale effect and error are analyzed from three aspects, namely, scale parameters, roughness and incident light angle direction. The results show that the dimensions, roughness and incident wavelength of the fiber material are in the sub-wavelength scale interval, which requires high model accuracy and gives the appropriate inversion range interval. Finally, the method is experimentally validated by using the natural silk fibers. This work constructs a complete set of theoretical models and experimental methods to accurately obtain the optical constants of actual fiber materials, which provides a new direction for obtaining the optical constants of fiber materials and a numerical basis for the study of the radiation modulation mechanism of fiber materials.","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"15 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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