Pub Date : 2022-10-31DOI: 10.1177/0309524X221130718
H. M. Yassin, Ramadan Ragab Abdel Wahab, H. H. Hanafy
This paper proposes an effective control technique for low voltage ride through (LVRT) capability in dual excited synchronous generator (DESG) wind turbines. The proposed control technique is dependent on controlling the field circuit parameters. Where the active power is controlled by the field-current space phasor magnitude and the reactive power is controlled by the field-voltage space phasor phase. With the proposed control strategy, the DESG can generate additional reactive power to support grid voltage recovery under grid faults. The DC-link voltage is kept within an acceptable limit since the excess power, due to the power mismatch between the mechanical and armature power is stored in the generator inertia. Using the proposed control strategy, the DESG can enhance the LVRT capability efficiently without using extra protection circuits or any additional control techniques during fault conditions. To test the proposed control method, simulation, and experimental results for a 1.1 kW DESG wind turbine system were obtained.
{"title":"Investigation of LVRT capability of wind driven dual excited synchronous generator","authors":"H. M. Yassin, Ramadan Ragab Abdel Wahab, H. H. Hanafy","doi":"10.1177/0309524X221130718","DOIUrl":"https://doi.org/10.1177/0309524X221130718","url":null,"abstract":"This paper proposes an effective control technique for low voltage ride through (LVRT) capability in dual excited synchronous generator (DESG) wind turbines. The proposed control technique is dependent on controlling the field circuit parameters. Where the active power is controlled by the field-current space phasor magnitude and the reactive power is controlled by the field-voltage space phasor phase. With the proposed control strategy, the DESG can generate additional reactive power to support grid voltage recovery under grid faults. The DC-link voltage is kept within an acceptable limit since the excess power, due to the power mismatch between the mechanical and armature power is stored in the generator inertia. Using the proposed control strategy, the DESG can enhance the LVRT capability efficiently without using extra protection circuits or any additional control techniques during fault conditions. To test the proposed control method, simulation, and experimental results for a 1.1 kW DESG wind turbine system were obtained.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"18 1","pages":"369 - 384"},"PeriodicalIF":1.5,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88054284","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 : 2022-10-28DOI: 10.1177/0309524X221127879
Víctor Pérez, C. Armenta-Déu
In this paper the influence of the wave oscillation on the behavior of floating off-shore wind turbine is analyzed. Aerodynamic analysis of forces on wind turbine blade has been carried out as a function of the wind turbine tilt angle due to wave oscillation. This analysis has resulted in a theoretical model based on the variation of the angle of attack which allows the characterization of the turbine under the effect of the oscillation of the sea surface. The results obtained show the influence of the oscillation in a particular case and its impact on the generated power. Subsequently, a so-called “pitching compensation” system that allows eliminating the effect produced by the variation in the angle of attack and, therefore, minimizing the effect of oscillation on the power generated, is proposed.
{"title":"Pitching compensation system to improve floating offshore wind turbine performance","authors":"Víctor Pérez, C. Armenta-Déu","doi":"10.1177/0309524X221127879","DOIUrl":"https://doi.org/10.1177/0309524X221127879","url":null,"abstract":"In this paper the influence of the wave oscillation on the behavior of floating off-shore wind turbine is analyzed. Aerodynamic analysis of forces on wind turbine blade has been carried out as a function of the wind turbine tilt angle due to wave oscillation. This analysis has resulted in a theoretical model based on the variation of the angle of attack which allows the characterization of the turbine under the effect of the oscillation of the sea surface. The results obtained show the influence of the oscillation in a particular case and its impact on the generated power. Subsequently, a so-called “pitching compensation” system that allows eliminating the effect produced by the variation in the angle of attack and, therefore, minimizing the effect of oscillation on the power generated, is proposed.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"211 1","pages":"299 - 310"},"PeriodicalIF":1.5,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77485701","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 : 2022-10-19DOI: 10.1177/0309524X221126743
M. Pohl, J. Riemenschneider
To increase the power yield, wind turbines have significantly grown in the last decades. Today, this growth is more and more limited by the weight of the structures and fatigue loads. To compensate these loads, especially flapwise root bending moments, trailing edge flaps can be used. They can change the lift of the blade with little delay to equalize the aerodynamic lift and by this reduce the fatigue amplitude. Such a trailing edge flap has been designed, developed, built and experimentally tested. It uses a flexible, morphing design to seal the entire mechanics against environmental influences, such as rain, dust, or insects. Therefore a design made from glass fiber reinforced plastics in combination with elastomer materials is used. In this paper the design process from the concept to two consecutive demonstrators is presented. Both are tested in the laboratory for their morphing characteristics.
{"title":"Design and laboratory tests of flexible trailing edge demonstrators for wind turbine blades","authors":"M. Pohl, J. Riemenschneider","doi":"10.1177/0309524X221126743","DOIUrl":"https://doi.org/10.1177/0309524X221126743","url":null,"abstract":"To increase the power yield, wind turbines have significantly grown in the last decades. Today, this growth is more and more limited by the weight of the structures and fatigue loads. To compensate these loads, especially flapwise root bending moments, trailing edge flaps can be used. They can change the lift of the blade with little delay to equalize the aerodynamic lift and by this reduce the fatigue amplitude. Such a trailing edge flap has been designed, developed, built and experimentally tested. It uses a flexible, morphing design to seal the entire mechanics against environmental influences, such as rain, dust, or insects. Therefore a design made from glass fiber reinforced plastics in combination with elastomer materials is used. In this paper the design process from the concept to two consecutive demonstrators is presented. Both are tested in the laboratory for their morphing characteristics.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"15 1","pages":"283 - 298"},"PeriodicalIF":1.5,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80097279","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 : 2022-10-18DOI: 10.1177/0309524X221127930
S. Tounsi
In this paper is presented an optimal control technology of wind energy system recovering energy in a battery energy accumulator. This control technology makes it possible to regulate the speed of the electric generator at its optimum value, to avoid any over-speed problems leading to strong increases in current in the electrical components of the wind turbine, and subsequently to its destruction. This control technology also makes it possible to maintain the induced electromotive forces in phase with the phase’s currents of the generator to have an additive electromagnetic torque, and in this way the recovered energy will be optimal. This control technology is based on two conversions, one is an Alternative-Continuous conversion performed by an AC-DC converter with IGBTs, and the other is a DC-DC conversion performed by a booster chopper to regulate the voltage of recharges batteries at its nominal value.
{"title":"Systemic optimal control of wind energy system regulating conjointly generator speed and battery recharging current","authors":"S. Tounsi","doi":"10.1177/0309524X221127930","DOIUrl":"https://doi.org/10.1177/0309524X221127930","url":null,"abstract":"In this paper is presented an optimal control technology of wind energy system recovering energy in a battery energy accumulator. This control technology makes it possible to regulate the speed of the electric generator at its optimum value, to avoid any over-speed problems leading to strong increases in current in the electrical components of the wind turbine, and subsequently to its destruction. This control technology also makes it possible to maintain the induced electromotive forces in phase with the phase’s currents of the generator to have an additive electromagnetic torque, and in this way the recovered energy will be optimal. This control technology is based on two conversions, one is an Alternative-Continuous conversion performed by an AC-DC converter with IGBTs, and the other is a DC-DC conversion performed by a booster chopper to regulate the voltage of recharges batteries at its nominal value.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"28 1","pages":"311 - 333"},"PeriodicalIF":1.5,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78175958","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 : 2022-10-17DOI: 10.1177/0309524X221130110
A. Kangash, M. Virk, P. Maryandyshev
This paper presents a study of the impact of icing on the performance of a pitch-regulated large wind turbine. Numerical simulations of six blade sections of the NREL 5 MW wind turbine at various free stream velocities are performed. Blade Element Momentum (BEM) method along Computational Fluid Dynamics (CFD) bases multiphase numerical simulations are used for this study. Analysis shows that the simulated parameters are in good agreement with the real conditions for each blade element during operation, except for the three-dimensional effects. The analysis of accreted ice shapes and air/droplet flow fields around the blade profile sections was carried out, and the calculation of aerodynamic performance, and energy production degradation was also performed. The tip of the blade is most affected by icing, it is characterized by the greatest changes in the aerodynamic performance. Maximum reduction in the wind turbine performance is estimated to be around 24%.
{"title":"Numerical study of icing impact on the performance of pitch-regulated large wind turbine","authors":"A. Kangash, M. Virk, P. Maryandyshev","doi":"10.1177/0309524X221130110","DOIUrl":"https://doi.org/10.1177/0309524X221130110","url":null,"abstract":"This paper presents a study of the impact of icing on the performance of a pitch-regulated large wind turbine. Numerical simulations of six blade sections of the NREL 5 MW wind turbine at various free stream velocities are performed. Blade Element Momentum (BEM) method along Computational Fluid Dynamics (CFD) bases multiphase numerical simulations are used for this study. Analysis shows that the simulated parameters are in good agreement with the real conditions for each blade element during operation, except for the three-dimensional effects. The analysis of accreted ice shapes and air/droplet flow fields around the blade profile sections was carried out, and the calculation of aerodynamic performance, and energy production degradation was also performed. The tip of the blade is most affected by icing, it is characterized by the greatest changes in the aerodynamic performance. Maximum reduction in the wind turbine performance is estimated to be around 24%.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"46 1","pages":"334 - 346"},"PeriodicalIF":1.5,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77831566","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 : 2022-10-17DOI: 10.1177/0309524X221124000
Ankur Maheshwari, Y. Sood, Supriya Jaiswal
Increased penetration of renewable energy sources (RESs) in power system networks poses several challenges in system planning and management due to their uncertain and non-dispatchable nature. Consequently, this paper presents a thorough and precise review of recent solution methodologies for solving the optimal power flow (OPF) problems incorporated with stochastic RESs based on multiple peer-reviewed research publications in reputed journals. The Teaching Learning Based Optimization algorithm has been discussed and implemented to solve the OPF problem considering solar photovoltaic, wind turbine, and tidal energy systems. Weibull, Lognormal, and Gumbel probability density functions representing the uncertainty associated with the availability of wind speed, solar irradiance, and tidal energy systems, respectively. The results obtained from the proposed technique validate its novelty regarding OPF problems like minimization of operating cost, power loss in transmission lines, enhancement of voltage profile, and voltage stability. The proposed solution technique for OPF problems is tested on a modified IEEE 30-bus test system. Thus, this study assists in understanding the OPF problem for new researchers concerned with this domain and also gives the idea of implementing nature-inspired optimization algorithms on a defined test system to solve the OPF problem.
{"title":"Investigation of optimal power flow solution techniques considering stochastic renewable energy sources: Review and analysis","authors":"Ankur Maheshwari, Y. Sood, Supriya Jaiswal","doi":"10.1177/0309524X221124000","DOIUrl":"https://doi.org/10.1177/0309524X221124000","url":null,"abstract":"Increased penetration of renewable energy sources (RESs) in power system networks poses several challenges in system planning and management due to their uncertain and non-dispatchable nature. Consequently, this paper presents a thorough and precise review of recent solution methodologies for solving the optimal power flow (OPF) problems incorporated with stochastic RESs based on multiple peer-reviewed research publications in reputed journals. The Teaching Learning Based Optimization algorithm has been discussed and implemented to solve the OPF problem considering solar photovoltaic, wind turbine, and tidal energy systems. Weibull, Lognormal, and Gumbel probability density functions representing the uncertainty associated with the availability of wind speed, solar irradiance, and tidal energy systems, respectively. The results obtained from the proposed technique validate its novelty regarding OPF problems like minimization of operating cost, power loss in transmission lines, enhancement of voltage profile, and voltage stability. The proposed solution technique for OPF problems is tested on a modified IEEE 30-bus test system. Thus, this study assists in understanding the OPF problem for new researchers concerned with this domain and also gives the idea of implementing nature-inspired optimization algorithms on a defined test system to solve the OPF problem.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"103 1","pages":"464 - 490"},"PeriodicalIF":1.5,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72547072","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 : 2022-10-17DOI: 10.1177/0309524X221130112
S. Tounsi
In this paper, is presented a design and control toll of electromechanical braking system dedicated to wind energy conversion chain. The braking system makes it possible to apply pressure strength at the level of the rotating shaft near to the propeller of the wind turbine. This pressure force is transformed into a dry friction force via the mechanical part of the braking system consisting of a piece of brake lining and steel of the rotating shaft of the propeller. A program of dimensioning by the analytical method of a permanent magnet linear motor structure is developed. The interactions between this program and the braking system control algorithm are taken into account. The integration of the global model under the Matlab-Simulink simulation environment allows full validation of the presented study.
{"title":"Optimal systemic combined design and control of an automated wind energy conversion system","authors":"S. Tounsi","doi":"10.1177/0309524X221130112","DOIUrl":"https://doi.org/10.1177/0309524X221130112","url":null,"abstract":"In this paper, is presented a design and control toll of electromechanical braking system dedicated to wind energy conversion chain. The braking system makes it possible to apply pressure strength at the level of the rotating shaft near to the propeller of the wind turbine. This pressure force is transformed into a dry friction force via the mechanical part of the braking system consisting of a piece of brake lining and steel of the rotating shaft of the propeller. A program of dimensioning by the analytical method of a permanent magnet linear motor structure is developed. The interactions between this program and the braking system control algorithm are taken into account. The integration of the global model under the Matlab-Simulink simulation environment allows full validation of the presented study.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"29 1","pages":"347 - 368"},"PeriodicalIF":1.5,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76257134","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 : 2022-10-05DOI: 10.1177/0309524X221130109
P. Coelho
The Betz’s limit for the maximum efficiency of an ideal wind turbine imposes a maximum value of about 60% on the conversion of the kinetic energy of an airflow into work. In this paper, we analyze the reason for this value because, from a thermodynamic point of view, it can be 100%. The present work explains the reason for this difference, since it appears to be relevant from a didactic point of view. However, from a practical point of view, the Betz’s limit does not affect in any way the more useful and widespread expression for calculating the ideal maximum power of a wind turbine, which is at the origin of the referred limit. Complementarily, two approaches for the calculation of the theoretical maximum efficiency, in line with thermodynamics, are also presented in this work.
{"title":"The Betz limit and the corresponding thermodynamic limit","authors":"P. Coelho","doi":"10.1177/0309524X221130109","DOIUrl":"https://doi.org/10.1177/0309524X221130109","url":null,"abstract":"The Betz’s limit for the maximum efficiency of an ideal wind turbine imposes a maximum value of about 60% on the conversion of the kinetic energy of an airflow into work. In this paper, we analyze the reason for this value because, from a thermodynamic point of view, it can be 100%. The present work explains the reason for this difference, since it appears to be relevant from a didactic point of view. However, from a practical point of view, the Betz’s limit does not affect in any way the more useful and widespread expression for calculating the ideal maximum power of a wind turbine, which is at the origin of the referred limit. Complementarily, two approaches for the calculation of the theoretical maximum efficiency, in line with thermodynamics, are also presented in this work.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"87 1","pages":"491 - 496"},"PeriodicalIF":1.5,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83557707","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}
Wind speed forecasting, a time series problem, plays a vital role in estimating annual wind energy production in wind farms. Calculation of wind energy helps to maintain stability between electricity production and consumption. Deep learning models are used for predicting time series data. However, as wind speed is non-stationary and irregular, pre-processing of these data is necessary to get accurate results. In this paper, static normalization techniques like min–max, z-score, and adaptive normalization are used for pre-processing wind datasets, and further, their forecasting results are compared. Adaptive normalization increases the learning rate and gives better forecasting results than static normalization. The RMSE value was reduced by 9.18% for the NREL dataset when adaptive normalization was used instead of z-score normalization and by 23.58% for the Weather dataset. The datasets used are taken from National Renewable Energy Laboratory (NREL) and Kaggle’s Dataset.
{"title":"Adaptive wind data normalization to improve the performance of forecasting models","authors":"Deepali Patil, Rajesh Wadhvani, Sanyam Shukla, Muktesh Gupta","doi":"10.1177/0309524X221093908","DOIUrl":"https://doi.org/10.1177/0309524X221093908","url":null,"abstract":"Wind speed forecasting, a time series problem, plays a vital role in estimating annual wind energy production in wind farms. Calculation of wind energy helps to maintain stability between electricity production and consumption. Deep learning models are used for predicting time series data. However, as wind speed is non-stationary and irregular, pre-processing of these data is necessary to get accurate results. In this paper, static normalization techniques like min–max, z-score, and adaptive normalization are used for pre-processing wind datasets, and further, their forecasting results are compared. Adaptive normalization increases the learning rate and gives better forecasting results than static normalization. The RMSE value was reduced by 9.18% for the NREL dataset when adaptive normalization was used instead of z-score normalization and by 23.58% for the Weather dataset. The datasets used are taken from National Renewable Energy Laboratory (NREL) and Kaggle’s Dataset.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"28 1","pages":"1606 - 1617"},"PeriodicalIF":1.5,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84701893","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 : 2022-10-01DOI: 10.1177/0309524X221080469
Y. Alonso, Arnoldo Bezanilla, Milena Alpizar, Yosvany Martinez-Gonzalez
An analysis of the behavior of the wind speed using the regional climate model PRECIS in high resolution scenarios of climate change RCPs is presented. The projections indicate that throughout the century, the speed of the surface wind will continue to increase to a greater or lesser extent (depending on the scenario) in most of the national territory, mainly towards the coast north, as an intensification and westward shift of the anticyclone North Atlantic could occur. The most important thing about this increase is that allows to consolidate the current projection of the Cuban wind program, in which the construction of 13 wind farms is proposed, precisely where the wind potential of Cuba will be increased. Finally this increase is added to the wind speed outputs of the Numerical Wind Atlas of Cuba to estimate the values of wind speed over the future periods.
{"title":"Wind energy resources assessment of Cuba using the regional climate model PRECIS in high resolution scenarios of climate change RCPs","authors":"Y. Alonso, Arnoldo Bezanilla, Milena Alpizar, Yosvany Martinez-Gonzalez","doi":"10.1177/0309524X221080469","DOIUrl":"https://doi.org/10.1177/0309524X221080469","url":null,"abstract":"An analysis of the behavior of the wind speed using the regional climate model PRECIS in high resolution scenarios of climate change RCPs is presented. The projections indicate that throughout the century, the speed of the surface wind will continue to increase to a greater or lesser extent (depending on the scenario) in most of the national territory, mainly towards the coast north, as an intensification and westward shift of the anticyclone North Atlantic could occur. The most important thing about this increase is that allows to consolidate the current projection of the Cuban wind program, in which the construction of 13 wind farms is proposed, precisely where the wind potential of Cuba will be increased. Finally this increase is added to the wind speed outputs of the Numerical Wind Atlas of Cuba to estimate the values of wind speed over the future periods.","PeriodicalId":51570,"journal":{"name":"Wind Engineering","volume":"43 1","pages":"1389 - 1407"},"PeriodicalIF":1.5,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86782553","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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