Pub Date : 2012-05-21DOI: 10.1109/APEMC.2012.6238010
A. Frech, P. Russer
According to the standard CISPR 16-2-3 measurements of electromagnetic interferences (EMI) are carried out either in anechoic chambers or on open area test sites. For testing on open test sites it is necessary to choose a remote location where man-made noise is minimum to avoid covering of the emissions of the device under test by ambient signals. The regulated measurement setup and procedure, described in the standard, is mandatory for compliance measurements and reproducible measurement results of radiated emission measurements in the range of 30MHz to 1 GHz. In this paper methods are presented to suppress unwanted ambient noise and thus allow to perform measurements on noise polluted open test sites. By using ultra high-speed analog-to-digital converters sampling the emissions signal in time-domain and applying the fast Fourier transformation EMI measurements are sped-up by several orders of magnitude compared to measurements carried out with traditional heterodyne receivers operating in frequency domain. Combining the time-domain technology together with adaptive filter techniques the presented system can perform ultra-fast emission measurements in the presence of ambient noise. Advanced strategies with real-time capability for adaptive noise cancellation based on a powerful hardware platform are shown. Frequency domain and time-domain adaptive filtering are compared. The adaptive filter algorithms are investigated and enhanced in respect of implementing the noise cancelling algorithm on field programmable gate arrays ensuring a continuously high data-throughput by an optimized digital signal processing in real-time. Measurements up to 1 GHz are carried out on inner urban sites. Ambient noise suppressing in real-time is shown in frequency bands of over 125MHz at once.
{"title":"Real-time ambient noise cancellation for EMI measurements on open area test sites","authors":"A. Frech, P. Russer","doi":"10.1109/APEMC.2012.6238010","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6238010","url":null,"abstract":"According to the standard CISPR 16-2-3 measurements of electromagnetic interferences (EMI) are carried out either in anechoic chambers or on open area test sites. For testing on open test sites it is necessary to choose a remote location where man-made noise is minimum to avoid covering of the emissions of the device under test by ambient signals. The regulated measurement setup and procedure, described in the standard, is mandatory for compliance measurements and reproducible measurement results of radiated emission measurements in the range of 30MHz to 1 GHz. In this paper methods are presented to suppress unwanted ambient noise and thus allow to perform measurements on noise polluted open test sites. By using ultra high-speed analog-to-digital converters sampling the emissions signal in time-domain and applying the fast Fourier transformation EMI measurements are sped-up by several orders of magnitude compared to measurements carried out with traditional heterodyne receivers operating in frequency domain. Combining the time-domain technology together with adaptive filter techniques the presented system can perform ultra-fast emission measurements in the presence of ambient noise. Advanced strategies with real-time capability for adaptive noise cancellation based on a powerful hardware platform are shown. Frequency domain and time-domain adaptive filtering are compared. The adaptive filter algorithms are investigated and enhanced in respect of implementing the noise cancelling algorithm on field programmable gate arrays ensuring a continuously high data-throughput by an optimized digital signal processing in real-time. Measurements up to 1 GHz are carried out on inner urban sites. Ambient noise suppressing in real-time is shown in frequency bands of over 125MHz at once.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130036538","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6238017
V. Ceperic, G. Gielen, A. Barić
A black-box method for modelling of conducted electromagnetic emissions (EME) at an integrated circuit (IC) power supply pin and ground level by adjustable complexity support vector regression machines (ACSVR) is presented. The ACSVR provides a basis for representing the nonlinear dynamic conducted EME. The ACSVR enables accurate modelling of conducted EME according to the IEC 61967-4 1Ω method and allows the adjustment of accuracy versus model simulation speed. As a test case, the EME model of conducted emissions of a 242-transistor voltage reference with offset compensation is presented. The resulting models (implemented in Verilog A) are accurate and fast to execute.
{"title":"Black-box modelling of conducted electromagnetic emissions by adjustable complexity support vector regression machines","authors":"V. Ceperic, G. Gielen, A. Barić","doi":"10.1109/APEMC.2012.6238017","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6238017","url":null,"abstract":"A black-box method for modelling of conducted electromagnetic emissions (EME) at an integrated circuit (IC) power supply pin and ground level by adjustable complexity support vector regression machines (ACSVR) is presented. The ACSVR provides a basis for representing the nonlinear dynamic conducted EME. The ACSVR enables accurate modelling of conducted EME according to the IEC 61967-4 1Ω method and allows the adjustment of accuracy versus model simulation speed. As a test case, the EME model of conducted emissions of a 242-transistor voltage reference with offset compensation is presented. The resulting models (implemented in Verilog A) are accurate and fast to execute.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130845745","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237988
I. Ahmed, E. Li
We present a review of our work on time domain simulation of devices from nano-electronics to nano-photonics. Different equations and models are incorporated into Maxwell equations. Schrödinger equation is incorporated into Maxwell equations to model nano-electronics and nano-plasmonics devices, Lorentz-Drude (LD) dispersive model to simulate passive plasmonic devices, whereas a solid state model consisting of Pauli Exclusion principle, state filling effect and dynamic Fermi-Dirac Thermalization is incorporated to model active nano-photonics devices. LD and solid state models are hybridized for the simulation of active plasmonics devices. Graphics processing unit (GPU) is used to enhance the simulation speed, and as an example one of the models is implemented on it.
{"title":"Time domain modeling: From nano-electronics to nano-photonics","authors":"I. Ahmed, E. Li","doi":"10.1109/APEMC.2012.6237988","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237988","url":null,"abstract":"We present a review of our work on time domain simulation of devices from nano-electronics to nano-photonics. Different equations and models are incorporated into Maxwell equations. Schrödinger equation is incorporated into Maxwell equations to model nano-electronics and nano-plasmonics devices, Lorentz-Drude (LD) dispersive model to simulate passive plasmonic devices, whereas a solid state model consisting of Pauli Exclusion principle, state filling effect and dynamic Fermi-Dirac Thermalization is incorporated to model active nano-photonics devices. LD and solid state models are hybridized for the simulation of active plasmonics devices. Graphics processing unit (GPU) is used to enhance the simulation speed, and as an example one of the models is implemented on it.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128976588","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237868
T. Kaufmann, C. Fumeaux
Meshless methods are a new type of numerical schemes in computational electromagnetics, combining the advantages of conformal unstructured modeling with the flexibility of a node distribution without an explicit mesh topology. A scattered field formulation of the meshless Radial Point Interpolation Method (RPIM) is introduced for efficient simulation of metallic structures. Scattering problems generally result in spherically radiated wavefronts, hence truncating the computational domain with locally radial perfectly matched layers (PML) appears more effective than with classical uniaxial PML. Therefore, such problems can be modelled using less memory and shorter computation times with spherical or cylindrical PML. The scattered field RPIM formulation with radial PML is verified in a classical scattering problem from a perfectly conducting cylinder. A comparison with the analytical Mie solution shows fast convergence rates which are indicative of low reflections from the PML boundary. A convergence analysis and a study on the PML thickness demonstrates how to extend the limits of the PML formulation.
{"title":"A scattered field formulation of the time-domain Radial Point Interpolation Method using radial perfectly matched layers","authors":"T. Kaufmann, C. Fumeaux","doi":"10.1109/APEMC.2012.6237868","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237868","url":null,"abstract":"Meshless methods are a new type of numerical schemes in computational electromagnetics, combining the advantages of conformal unstructured modeling with the flexibility of a node distribution without an explicit mesh topology. A scattered field formulation of the meshless Radial Point Interpolation Method (RPIM) is introduced for efficient simulation of metallic structures. Scattering problems generally result in spherically radiated wavefronts, hence truncating the computational domain with locally radial perfectly matched layers (PML) appears more effective than with classical uniaxial PML. Therefore, such problems can be modelled using less memory and shorter computation times with spherical or cylindrical PML. The scattered field RPIM formulation with radial PML is verified in a classical scattering problem from a perfectly conducting cylinder. A comparison with the analytical Mie solution shows fast convergence rates which are indicative of low reflections from the PML boundary. A convergence analysis and a study on the PML thickness demonstrates how to extend the limits of the PML formulation.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125521432","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237939
M. Coenen, T. Gierstberg, A. V. van Roermund
Most often, it is unclear where assembled PCBs are going to be used in and how these are being connected and applied. As such, it will be required, both for the OEM manufacturer as well as the end-user/system integrator, to know the EMC properties prior to system integration. EMC is, aside power integrity (PI) and signal integrity (SI), one of the crucial requirements to be met to ensure functional reliability of the end-product. The EMC requirements applicable need to be uncomplicated and easy to verify in a limited amount of test time. Last but not least, these EMC tests have to be applied in an environment which is close to the end-applications foreseen; rack-mounted, stand-alone, etc. The PCB test methods proposed cover the frequency range from (DC) several Hz to several GHz, both on RF emission and immunity. By exchanging the RF disturbance source by an impulse source, the test methods proposed can also be used with impulse immunity tests.
{"title":"Assembled PCB EMC test methods","authors":"M. Coenen, T. Gierstberg, A. V. van Roermund","doi":"10.1109/APEMC.2012.6237939","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237939","url":null,"abstract":"Most often, it is unclear where assembled PCBs are going to be used in and how these are being connected and applied. As such, it will be required, both for the OEM manufacturer as well as the end-user/system integrator, to know the EMC properties prior to system integration. EMC is, aside power integrity (PI) and signal integrity (SI), one of the crucial requirements to be met to ensure functional reliability of the end-product. The EMC requirements applicable need to be uncomplicated and easy to verify in a limited amount of test time. Last but not least, these EMC tests have to be applied in an environment which is close to the end-applications foreseen; rack-mounted, stand-alone, etc. The PCB test methods proposed cover the frequency range from (DC) several Hz to several GHz, both on RF emission and immunity. By exchanging the RF disturbance source by an impulse source, the test methods proposed can also be used with impulse immunity tests.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117122095","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237808
Y. S. Meng, Y. Shan, H. Neo
In this paper, the development of a waveguide microwave power sensor calibration system is reported. This system is a physical realization of the direct comparison transfer of waveguide microwave power sensor calibration up to 110 GHz. For the developed calibration system, the measurement uncertainty is discussed and evaluated, where the major uncertainty contributor for the current system is identified. To further improve the performance of our system and reduce the cost of calibration, some necessary future work is planned.
{"title":"Development of a waveguide microwave power sensor calibration system at NMC","authors":"Y. S. Meng, Y. Shan, H. Neo","doi":"10.1109/APEMC.2012.6237808","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237808","url":null,"abstract":"In this paper, the development of a waveguide microwave power sensor calibration system is reported. This system is a physical realization of the direct comparison transfer of waveguide microwave power sensor calibration up to 110 GHz. For the developed calibration system, the measurement uncertainty is discussed and evaluated, where the major uncertainty contributor for the current system is identified. To further improve the performance of our system and reduce the cost of calibration, some necessary future work is planned.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125557412","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237958
B. V. Ha, M. Maglio, R. Zich
The application of a wireless energy transfer system to a rotating shaft is analyzed in this paper. Energy transfer without contacts is critical in a large number of applications. The use of slip ring contacts between the power feeder and the rotating system can bring a lot of drawbacks and can damage the entire structure[1]. The use of a contactless energy transfer system could overcome all these drawbacks in particular where the maintenance time is very expensive and the access to the system parts could be hard to do.
{"title":"Contactless energy transfer in adverse environment using rectennas","authors":"B. V. Ha, M. Maglio, R. Zich","doi":"10.1109/APEMC.2012.6237958","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237958","url":null,"abstract":"The application of a wireless energy transfer system to a rotating shaft is analyzed in this paper. Energy transfer without contacts is critical in a large number of applications. The use of slip ring contacts between the power feeder and the rotating system can bring a lot of drawbacks and can damage the entire structure[1]. The use of a contactless energy transfer system could overcome all these drawbacks in particular where the maintenance time is very expensive and the access to the system parts could be hard to do.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126015077","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237948
R. Chang, K. See, Weishan Soh, Yew-Huat Ong, W. Huang
Today's digital data lines are clocking at very high speed, in excess of 100MHz with rise time in the sub-nano second range. The effects of EMI radiation even from short traces are becoming significant and cannot be ignored. The use of resistive termination versus the EMI filter has long been a compromise in terms of cost and necessity. EMI compliance is now becoming a major design challenge for product development rather than a mere good-to-have specification of low emission. This paper carries out a comprehensive study on filter selection, application, impact on receiver waveform signal integrity and far-field emission suppression using a full-wave electromagnetic simulator (CST Microwave Studio). This study will provide high-speed digital designers an in-depth assessment of the use of EMI filter for radiation suppression in high-speed digital layout.
{"title":"Impacts of EMI filter on high speed interconnects for digital circuits design","authors":"R. Chang, K. See, Weishan Soh, Yew-Huat Ong, W. Huang","doi":"10.1109/APEMC.2012.6237948","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237948","url":null,"abstract":"Today's digital data lines are clocking at very high speed, in excess of 100MHz with rise time in the sub-nano second range. The effects of EMI radiation even from short traces are becoming significant and cannot be ignored. The use of resistive termination versus the EMI filter has long been a compromise in terms of cost and necessity. EMI compliance is now becoming a major design challenge for product development rather than a mere good-to-have specification of low emission. This paper carries out a comprehensive study on filter selection, application, impact on receiver waveform signal integrity and far-field emission suppression using a full-wave electromagnetic simulator (CST Microwave Studio). This study will provide high-speed digital designers an in-depth assessment of the use of EMI filter for radiation suppression in high-speed digital layout.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126904859","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237903
Oussama Alilou, V. Fontaine, C. Marot
Electronic boards will become higher density of integration with lower supply voltages. Internal integrated Circuits have more and more gates on silicon and Printed circuits Boards use many high density technologies. That size reduction integration with nearby signals positions promotes internal crosstalk, sizes reduction of die geometries increases unwanted current in parasitic structure as isolation capacitances. Consequently, the immunity of electronic boards is becoming more and more critical and the use of models and simulation tools is hardly required to optimize during the design phases the susceptibility behaviour and also to predict the immunity strength to conducted disturbances both at the IC and the application level. This paper introduces in section I an overview of the IEC projects for Integrated Circuit modelling. An immunity model for an electronic board is described in section II. Example model of driver bus is presented in a part III. Simulation results of a immunity test with that driver immunity model is presented in a part IV.
{"title":"Immunity modelling of electronics board","authors":"Oussama Alilou, V. Fontaine, C. Marot","doi":"10.1109/APEMC.2012.6237903","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237903","url":null,"abstract":"Electronic boards will become higher density of integration with lower supply voltages. Internal integrated Circuits have more and more gates on silicon and Printed circuits Boards use many high density technologies. That size reduction integration with nearby signals positions promotes internal crosstalk, sizes reduction of die geometries increases unwanted current in parasitic structure as isolation capacitances. Consequently, the immunity of electronic boards is becoming more and more critical and the use of models and simulation tools is hardly required to optimize during the design phases the susceptibility behaviour and also to predict the immunity strength to conducted disturbances both at the IC and the application level. This paper introduces in section I an overview of the IEC projects for Integrated Circuit modelling. An immunity model for an electronic board is described in section II. Example model of driver bus is presented in a part III. Simulation results of a immunity test with that driver immunity model is presented in a part IV.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127170061","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 : 2012-05-21DOI: 10.1109/APEMC.2012.6237866
A. Al-Kalbani, M. Yuce, Jean-Michel Redouté
This paper discusses the simulated exposure to a 5 MHz electromagnetic field powering implanted electronic devices using an inductive link. A high efficiency class-E transmitter circuit operating at 5 MHz has been designed. The circuit generates a 1 W to 5 W transmitted power by means of two possible planar primary coil designs, and powers 5 identical implants which are individually equipped with a secondary inductor. Simulations illustrate that a maximum localized SAR level (averaged over 10 g) of 1.16 W/kg is obtained in a rectangular bone structure with a thickness of 10 mm, when the power transmission is equal to 5 W.
{"title":"Specific absorption rate of inductively powered brain implanted circuits","authors":"A. Al-Kalbani, M. Yuce, Jean-Michel Redouté","doi":"10.1109/APEMC.2012.6237866","DOIUrl":"https://doi.org/10.1109/APEMC.2012.6237866","url":null,"abstract":"This paper discusses the simulated exposure to a 5 MHz electromagnetic field powering implanted electronic devices using an inductive link. A high efficiency class-E transmitter circuit operating at 5 MHz has been designed. The circuit generates a 1 W to 5 W transmitted power by means of two possible planar primary coil designs, and powers 5 identical implants which are individually equipped with a secondary inductor. Simulations illustrate that a maximum localized SAR level (averaged over 10 g) of 1.16 W/kg is obtained in a rectangular bone structure with a thickness of 10 mm, when the power transmission is equal to 5 W.","PeriodicalId":300639,"journal":{"name":"2012 Asia-Pacific Symposium on Electromagnetic Compatibility","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126182241","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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