Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814210
T. Mazloum, Shanshan Wang, J. Wiart
We aim in the present paper to address the impact of installing indoor distributed antenna system (distAS) on the human exposure to radio-frequency electromagnetic field (RF-EMF). We note that distAS aims to extend coverage and improve wireless communication quality. We performed measurement campaigns in subway stations, where distAS are deployed. The impact of distAS on the exposure is studied by considering two scenarios where distAS are turned either on or off. The electric field strength is measured at different distances to the distAS, for all the frequency bands and operators. The results show that the DL exposure induced by distAS is very low and far away from the standard limits of ICNIRP.
{"title":"RF-EMF exposure induced by distributed antenna system in the subway station","authors":"T. Mazloum, Shanshan Wang, J. Wiart","doi":"10.23919/AT-AP-RASC54737.2022.9814210","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814210","url":null,"abstract":"We aim in the present paper to address the impact of installing indoor distributed antenna system (distAS) on the human exposure to radio-frequency electromagnetic field (RF-EMF). We note that distAS aims to extend coverage and improve wireless communication quality. We performed measurement campaigns in subway stations, where distAS are deployed. The impact of distAS on the exposure is studied by considering two scenarios where distAS are turned either on or off. The electric field strength is measured at different distances to the distAS, for all the frequency bands and operators. The results show that the DL exposure induced by distAS is very low and far away from the standard limits of ICNIRP.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131557888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814283
M. Morgan
Geometric or Clifford algebra is a powerful, coordinate-free language for mathematical physics, offering more compact and insightful descriptions of natural laws than existing legacy formalisms in areas ranging from basic geometry and complex analysis to quantum mechanics and general relativity [1]–[5]. In its four-dimensional form employing the Minkowski metric, known as spacetime algebra, it is extraordinarily effective at describing electrodynamics in a relativistic framework, compressing Maxwell's equations into one simple expression that applies independent of any preferred inertial reference frame.However, as the practitioners of spacetime algebra have typically come from either a pure mathematics or theoretical physics background, only the microscopic form of Maxwell's equation, that which applies to fundamental particles in a vacuum, has received widespread attention. The conventional macroscopic simplification used by engineers, wherein the effects of bound charges and currents in a dielectric medium are subsumed into phenomenological constituent parameters—the relative permittivity and permeability—is frequently neglected.In this paper I describe a macroscopic form of Maxwell's equation in spacetime algebra where only free charges and currents appear explicitly.
{"title":"A Macroscopic Field Equation in Spacetime Algebra","authors":"M. Morgan","doi":"10.23919/AT-AP-RASC54737.2022.9814283","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814283","url":null,"abstract":"Geometric or Clifford algebra is a powerful, coordinate-free language for mathematical physics, offering more compact and insightful descriptions of natural laws than existing legacy formalisms in areas ranging from basic geometry and complex analysis to quantum mechanics and general relativity [1]–[5]. In its four-dimensional form employing the Minkowski metric, known as spacetime algebra, it is extraordinarily effective at describing electrodynamics in a relativistic framework, compressing Maxwell's equations into one simple expression that applies independent of any preferred inertial reference frame.However, as the practitioners of spacetime algebra have typically come from either a pure mathematics or theoretical physics background, only the microscopic form of Maxwell's equation, that which applies to fundamental particles in a vacuum, has received widespread attention. The conventional macroscopic simplification used by engineers, wherein the effects of bound charges and currents in a dielectric medium are subsumed into phenomenological constituent parameters—the relative permittivity and permeability—is frequently neglected.In this paper I describe a macroscopic form of Maxwell's equation in spacetime algebra where only free charges and currents appear explicitly.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127613507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814236
V. van Tonder, L. Schwardt, A. Faustmann, J. Gilmore
Radio telescopes are becoming more powerful, with increased sensitivity to both astronomical and interfering sources. Various interference mitigation techniques exist, however they could be harmful to the signal of interest, thus it is important to develop new techniques. Majority of radio astronomical sources are considered to have a Gaussian distribution which are fully characterised using second-order power statistics. Higher-order statistics is a tool that can suppress Gaussian noise, therefore if interference have energy in higher domains it could form the basis for a new mitigation technique. This work uses a third-order statistic, the bispectrum, to conduct analysis on global positioning system (GPS) signals. It is found that one of the in-phase components of GPS signals has energy in the bispectrum.
{"title":"Bispectra of simulated GPS data for potential RFI mitigation","authors":"V. van Tonder, L. Schwardt, A. Faustmann, J. Gilmore","doi":"10.23919/AT-AP-RASC54737.2022.9814236","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814236","url":null,"abstract":"Radio telescopes are becoming more powerful, with increased sensitivity to both astronomical and interfering sources. Various interference mitigation techniques exist, however they could be harmful to the signal of interest, thus it is important to develop new techniques. Majority of radio astronomical sources are considered to have a Gaussian distribution which are fully characterised using second-order power statistics. Higher-order statistics is a tool that can suppress Gaussian noise, therefore if interference have energy in higher domains it could form the basis for a new mitigation technique. This work uses a third-order statistic, the bispectrum, to conduct analysis on global positioning system (GPS) signals. It is found that one of the in-phase components of GPS signals has energy in the bispectrum.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131227103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814341
T. Pisanu, G. Valente, P. Marongiu, P. Maxia, P. Ortu, A. Navarrini, A. Ladu, L. Schirru, R. Ghiani, R. Concu, F. Gaudiomonte, G. Angius, A. Cabras, E. Egron, N. Iacolina, V. Vacca
We describe the development status of the S-band (3-4.5 GHz) seven-beam cryogenic receiver for the primary focus of the Sardinia Radio Telescope (SRT). The main scientific goals for the SRT at S-band include the search for new pulsars, the evaluation of the pulsar dispersion for gravitational wave measurements, the mapping of galactic supernova remnants, and the study of magnetic field of galaxy clusters.
{"title":"Status of the multibeam S band receiver for the Sardinia Radio Telescope","authors":"T. Pisanu, G. Valente, P. Marongiu, P. Maxia, P. Ortu, A. Navarrini, A. Ladu, L. Schirru, R. Ghiani, R. Concu, F. Gaudiomonte, G. Angius, A. Cabras, E. Egron, N. Iacolina, V. Vacca","doi":"10.23919/AT-AP-RASC54737.2022.9814341","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814341","url":null,"abstract":"We describe the development status of the S-band (3-4.5 GHz) seven-beam cryogenic receiver for the primary focus of the Sardinia Radio Telescope (SRT). The main scientific goals for the SRT at S-band include the search for new pulsars, the evaluation of the pulsar dispersion for gravitational wave measurements, the mapping of galactic supernova remnants, and the study of magnetic field of galaxy clusters.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133555994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814201
Haya Al Kassir, Z. Zaharis, P. Lazaridis, N. Kantartzis, T. Yioultsis, I. Chochliouros, A. Mihovska, T. Xenos
The implementation of antenna array beamforming using several neural network (NN) architectures is compared in this paper. Gated recurrent unit, feed-forward NN, convolutional NN, and long short-term memory architectures have been used for the beamforming process. This comparative study is carried out using various metrics, such as the root mean square error, and the computational time for each NN. In addition, the mean absolute divergences of the antenna array main lobe and nulls directions from their respective desired directions have also been used to assess the performance of each beamformer. The neural networks are trained using the simulation results of a 16-element microstrip patch antenna array. It is demonstrated that deep learning-based beamformers are capable of computing optimum antenna array weights in real time and in environments that change with time.
{"title":"Antenna Array Beamforming Based on Deep Learning Neural Network Architectures","authors":"Haya Al Kassir, Z. Zaharis, P. Lazaridis, N. Kantartzis, T. Yioultsis, I. Chochliouros, A. Mihovska, T. Xenos","doi":"10.23919/AT-AP-RASC54737.2022.9814201","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814201","url":null,"abstract":"The implementation of antenna array beamforming using several neural network (NN) architectures is compared in this paper. Gated recurrent unit, feed-forward NN, convolutional NN, and long short-term memory architectures have been used for the beamforming process. This comparative study is carried out using various metrics, such as the root mean square error, and the computational time for each NN. In addition, the mean absolute divergences of the antenna array main lobe and nulls directions from their respective desired directions have also been used to assess the performance of each beamformer. The neural networks are trained using the simulation results of a 16-element microstrip patch antenna array. It is demonstrated that deep learning-based beamformers are capable of computing optimum antenna array weights in real time and in environments that change with time.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132279926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814418
A. Goudarzi, M. M. Honari, A. Gharaati, R. Mirzavand
This paper presents a Millimeter-Wave (mm-wave) resonat cavity (RC) structure with high gain and low sidelobe level (SLL). It consists of a 5×5 dipole antenna array as a main radiator fed by a series feeding network. The network is designed based on the Chebyshev distribution to decrease the SLL. A partially reflective surface (PRS) is designed and placed above the dipole array to improve the RC radiation characteristics. All dipoles arranged in a separated row are connected by a series network with Chebyshev distribution weights. A vertically-placed series feeding network is applied to feed all five rows of the dipole array and is enclosed by a metallic cavity to decrease the undesired backward radiations resulting from the vertical feeding line. It is observed that the sidelobe level can be reduced to -32 dB and -27 dB at E-plane and H-plane, respectively. Also, a high gain of 22 dBi is achieved at 28 GHz.
{"title":"A Millimeter-Wave Resonant Cavity Antenna with High Gain and Low Sidelobe Level","authors":"A. Goudarzi, M. M. Honari, A. Gharaati, R. Mirzavand","doi":"10.23919/AT-AP-RASC54737.2022.9814418","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814418","url":null,"abstract":"This paper presents a Millimeter-Wave (mm-wave) resonat cavity (RC) structure with high gain and low sidelobe level (SLL). It consists of a 5×5 dipole antenna array as a main radiator fed by a series feeding network. The network is designed based on the Chebyshev distribution to decrease the SLL. A partially reflective surface (PRS) is designed and placed above the dipole array to improve the RC radiation characteristics. All dipoles arranged in a separated row are connected by a series network with Chebyshev distribution weights. A vertically-placed series feeding network is applied to feed all five rows of the dipole array and is enclosed by a metallic cavity to decrease the undesired backward radiations resulting from the vertical feeding line. It is observed that the sidelobe level can be reduced to -32 dB and -27 dB at E-plane and H-plane, respectively. Also, a high gain of 22 dBi is achieved at 28 GHz.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131286057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814350
A. Boaventura
We present a dc superconducting quantum interference device (dc-SQUID) model for the design and optimization of quantum-limited parametric amplifiers. These devices are critical for superconducting quantum computing and do not currently have comprehensive models that designers can use to simulate their circuits in standard circuit simulators. Our model has been implemented and tested in the Advanced Design Systems (ADS) simulation software and validated against analytical predictions.
{"title":"A Superconducting Quantum Interference Device Model for the Design and Optimization of Quantum-Limited Microwave Amplifiers in Harmonic Balance Simulators","authors":"A. Boaventura","doi":"10.23919/AT-AP-RASC54737.2022.9814350","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814350","url":null,"abstract":"We present a dc superconducting quantum interference device (dc-SQUID) model for the design and optimization of quantum-limited parametric amplifiers. These devices are critical for superconducting quantum computing and do not currently have comprehensive models that designers can use to simulate their circuits in standard circuit simulators. Our model has been implemented and tested in the Advanced Design Systems (ADS) simulation software and validated against analytical predictions.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127239415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814213
A. Argyriou
Detecting the number of sources from which the signal of a single wireless transmitter has originated, as well as estimating its angle-of-arrival (AoA), are critical parameters for a plethora of remote sensing applications (e.g. military, localization, radio-astronomy, etc.). A rather interesting observation is that these two problems are inter-twined since the most popular solution is based on eigenvalue decomposition (EGD) of the correlation matrix of the received signal. The Akaike information criterio (AIC) has been used in conjunction with EGD for detecting the number of sources or the number of AoAs (the later is a pre-requisite for AoA estimation). In this work we present an algorithm for a two-step application of AIC so that we can detect simultaneously the number of sources and AoAs for a MIMO transmitter that operates in a multipath environment. Results indicate the good performance of the proposed scheme for different multipath topologies and system configurations.
{"title":"Number of Sources Detection and AoA Estimation of a Wireless Transmitter in Multipath Channels","authors":"A. Argyriou","doi":"10.23919/AT-AP-RASC54737.2022.9814213","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814213","url":null,"abstract":"Detecting the number of sources from which the signal of a single wireless transmitter has originated, as well as estimating its angle-of-arrival (AoA), are critical parameters for a plethora of remote sensing applications (e.g. military, localization, radio-astronomy, etc.). A rather interesting observation is that these two problems are inter-twined since the most popular solution is based on eigenvalue decomposition (EGD) of the correlation matrix of the received signal. The Akaike information criterio (AIC) has been used in conjunction with EGD for detecting the number of sources or the number of AoAs (the later is a pre-requisite for AoA estimation). In this work we present an algorithm for a two-step application of AIC so that we can detect simultaneously the number of sources and AoAs for a MIMO transmitter that operates in a multipath environment. Results indicate the good performance of the proposed scheme for different multipath topologies and system configurations.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"169 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128851568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814217
M. Bevacqua, T. Isernia
In this contribution a new method for inverse obstacle scattering problem is proposed starting from a recently introduced smart rewriting of the scattering equations, known as New Integral Equation (NIE) model. This latter involves a redefinition of the contrast function encoding the target properties. Interestingly, in both cases of strong and metallic scatterers, this function turns to be approximatively real, homogenous and approaching the unitary value. These properties are then exploited in the proposed method to accurately retrieve the shape and size of strong and/or metallic targets, as described in the following.
{"title":"Exploiting the NIE model for the inverse obstacle scattering problem in case of strong or metallic scatterers","authors":"M. Bevacqua, T. Isernia","doi":"10.23919/AT-AP-RASC54737.2022.9814217","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814217","url":null,"abstract":"In this contribution a new method for inverse obstacle scattering problem is proposed starting from a recently introduced smart rewriting of the scattering equations, known as New Integral Equation (NIE) model. This latter involves a redefinition of the contrast function encoding the target properties. Interestingly, in both cases of strong and metallic scatterers, this function turns to be approximatively real, homogenous and approaching the unitary value. These properties are then exploited in the proposed method to accurately retrieve the shape and size of strong and/or metallic targets, as described in the following.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114821579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-29DOI: 10.23919/AT-AP-RASC54737.2022.9814200
M. A. Kriele, R. Wayth, M. Bentum, B. Juswardy, C. Trott
We present multi-system spherical harmonic transit interferometry, an extension to the m-mode formalism, allowing for the inclusion of multiple interferometric systems to account for missing information on the sky; alleviating the need for prior fitting and/or regression. We simulate data with two model topologies to show we can indeed recover a genuine all-sky map. Furthermore, we explain how including multiple systems affects point-spread functions (PSFs) across declination, as well as how this method helps improving spatial coverage on the sky.
{"title":"Multi-system All-sky Spherical Harmonic Transit Interferometry","authors":"M. A. Kriele, R. Wayth, M. Bentum, B. Juswardy, C. Trott","doi":"10.23919/AT-AP-RASC54737.2022.9814200","DOIUrl":"https://doi.org/10.23919/AT-AP-RASC54737.2022.9814200","url":null,"abstract":"We present multi-system spherical harmonic transit interferometry, an extension to the m-mode formalism, allowing for the inclusion of multiple interferometric systems to account for missing information on the sky; alleviating the need for prior fitting and/or regression. We simulate data with two model topologies to show we can indeed recover a genuine all-sky map. Furthermore, we explain how including multiple systems affects point-spread functions (PSFs) across declination, as well as how this method helps improving spatial coverage on the sky.","PeriodicalId":356067,"journal":{"name":"2022 3rd URSI Atlantic and Asia Pacific Radio Science Meeting (AT-AP-RASC)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117264484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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