Pub Date : 2011-05-11DOI: 10.1109/POWERENG.2011.6036571
A. Gómez-Expósito, J. Maza-Ortega, E. Romero-Ramos, A. Marano
Distribution systems, and more specifically medium voltage (MV) networks, have not reached the automation level and technological sophistication of transmission systems. In fact, the introduction of the smart grid concept simply recognizes the urgent need and opportunity to improve the performance of distribution networks, in view of the new challenges they are facing nowadays. MV systems, being structurally meshed, are however radially operated. Until recently, the absence of any generation at this level has invariably led energy to flow from the substation to distribution transformers. This significantly simplifies both the operation of these systems and the design of the protection equipment. Owing to the need of assuring back-up supply, radial feeders are customarily oversized so that they can serve, at least partially, the load of neighboring feeders in case of fault. In this context, the growing presence of dispersed generation (DG) is, on the one hand, reducing the spare feeder capacity, leading in many cases to congestions, and, on the other, complicating the operation and protection schemes. The use of power electronic devices is seen as a promising way of enhancing both asset utilization and massive DG penetration, much in the same way HVDC systems were introduced decades ago at the transmission level. More specifically, in this work smart links between MV feeders and tap changers for distribution transformers, both based on electronic devices, are considered and assessed on actual distribution systems. These devices are sized and placed during a preliminary planning stage in order to maximize the dispersed generation that can be accommodated and/or the system loadability. Then, during the operational stage, the associated control variables are scheduled according to a new optimization problem intended to balance the load among bridged feeders or to minimize power losses. A simplified economic assessment is also included in order to prove that these smart devices can be a profitable investment, not only for utilities but also for the owners of DG.
{"title":"Smart links for distribution networks: The right way to further integrate renewables","authors":"A. Gómez-Expósito, J. Maza-Ortega, E. Romero-Ramos, A. Marano","doi":"10.1109/POWERENG.2011.6036571","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036571","url":null,"abstract":"Distribution systems, and more specifically medium voltage (MV) networks, have not reached the automation level and technological sophistication of transmission systems. In fact, the introduction of the smart grid concept simply recognizes the urgent need and opportunity to improve the performance of distribution networks, in view of the new challenges they are facing nowadays. MV systems, being structurally meshed, are however radially operated. Until recently, the absence of any generation at this level has invariably led energy to flow from the substation to distribution transformers. This significantly simplifies both the operation of these systems and the design of the protection equipment. Owing to the need of assuring back-up supply, radial feeders are customarily oversized so that they can serve, at least partially, the load of neighboring feeders in case of fault. In this context, the growing presence of dispersed generation (DG) is, on the one hand, reducing the spare feeder capacity, leading in many cases to congestions, and, on the other, complicating the operation and protection schemes. The use of power electronic devices is seen as a promising way of enhancing both asset utilization and massive DG penetration, much in the same way HVDC systems were introduced decades ago at the transmission level. More specifically, in this work smart links between MV feeders and tap changers for distribution transformers, both based on electronic devices, are considered and assessed on actual distribution systems. These devices are sized and placed during a preliminary planning stage in order to maximize the dispersed generation that can be accommodated and/or the system loadability. Then, during the operational stage, the associated control variables are scheduled according to a new optimization problem intended to balance the load among bridged feeders or to minimize power losses. A simplified economic assessment is also included in order to prove that these smart devices can be a profitable investment, not only for utilities but also for the owners of DG.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132244603","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036556
J. Molina, L. Sainz, J. J. Mesas
The current number of magnetic and electronic ballast discharge lamps in power distribution systems is increasing because they perform better than incandescent lamps. This paper studies the magnetic discharge lamp modeling. In particular, the arc voltage waveform is analyzed and the limitations of the square waveform model are revealed from experimental measurements.
{"title":"On the square arc voltage waveform model in magnetic discharge lamp studies","authors":"J. Molina, L. Sainz, J. J. Mesas","doi":"10.1109/POWERENG.2011.6036556","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036556","url":null,"abstract":"The current number of magnetic and electronic ballast discharge lamps in power distribution systems is increasing because they perform better than incandescent lamps. This paper studies the magnetic discharge lamp modeling. In particular, the arc voltage waveform is analyzed and the limitations of the square waveform model are revealed from experimental measurements.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114430105","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036515
I. Colak, R. Bayindir, E. Irmak, O. Kaplan
In recent years, interest to active power filters has been increased. This paper presents a comparative evaluation for two types of harmonic extraction methods used widely for single phase shunt active power filters which are the p-q theory and the sine multiplying method. These control theories are investigated in detail considering their mathematical models. The performance of each theory is examined on the simulation circuit built in MATLAB/Simulink toolbox. Results show that the sine multiplying method is better than the single phase p-q theory in terms of THD.
{"title":"A comparative study of harmonic extraction methods for single phase shunt active power filter","authors":"I. Colak, R. Bayindir, E. Irmak, O. Kaplan","doi":"10.1109/POWERENG.2011.6036515","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036515","url":null,"abstract":"In recent years, interest to active power filters has been increased. This paper presents a comparative evaluation for two types of harmonic extraction methods used widely for single phase shunt active power filters which are the p-q theory and the sine multiplying method. These control theories are investigated in detail considering their mathematical models. The performance of each theory is examined on the simulation circuit built in MATLAB/Simulink toolbox. Results show that the sine multiplying method is better than the single phase p-q theory in terms of THD.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114836519","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036567
O. Barambones, J. M. G. de Durana
The actual wind turbines are provided with adjustable speed generators, like the double feed induction generator, that are capable to work in variable speed operations. One of the main advantage of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators because turbine speed is adjusted as a function of wind speed to maximize output power. However this systems requires a suitable speed controller in order to track the optimal wind turbine reference speed. In this work, an adaptive robust control for variable speed wind power generator is described. The proposed robust control law is based on a sliding mode control theory, that presents a good performance under system uncertainties. The proposed sliding-mode control law incorporates an adaptive switching gain, which avoids having to calculate an upper limit of the system uncertainties that is necessary in the traditional sliding-mode control laws. The stability analysis of the proposed controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally simulated results show, on the one hand that the proposed controller provides high-performance dynamic characteristics, and on the other hand that this scheme is robust with respect to plant parameter variations and external disturbances.
{"title":"An adaptive sliding mode control law for the power maximization of the wind turbine system","authors":"O. Barambones, J. M. G. de Durana","doi":"10.1109/POWERENG.2011.6036567","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036567","url":null,"abstract":"The actual wind turbines are provided with adjustable speed generators, like the double feed induction generator, that are capable to work in variable speed operations. One of the main advantage of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators because turbine speed is adjusted as a function of wind speed to maximize output power. However this systems requires a suitable speed controller in order to track the optimal wind turbine reference speed. In this work, an adaptive robust control for variable speed wind power generator is described. The proposed robust control law is based on a sliding mode control theory, that presents a good performance under system uncertainties. The proposed sliding-mode control law incorporates an adaptive switching gain, which avoids having to calculate an upper limit of the system uncertainties that is necessary in the traditional sliding-mode control laws. The stability analysis of the proposed controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally simulated results show, on the one hand that the proposed controller provides high-performance dynamic characteristics, and on the other hand that this scheme is robust with respect to plant parameter variations and external disturbances.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125441651","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036529
N. Ginot, C. Batard, M. Mannah, M. Machmoum
The use of electrical power supply networks as a communication medium is currently under development. For example, Power Line Communication (PLC) allows nowadays interconnecting high-speed multimedia equipments while using the electrical mains supply. This paper revolves around this theme, but is purely dedicated to the Pulse Width Modulation (PWM) electrical network. The PWM power supplies are used in industrial applications such as motor drive application. The work in progress is at the boundary of two distinct fields: communication and high currents. Firstly, we underline the limits of functioning of the PLC modems on a PWM power supply. Subsequently, a filtering solution employing passive filters is discussed. Finally, the development of a new modem dedicated to PWM power supply is presented and inserted in a motor drive application. Experimental results show the ability of the modem to transmit high-speed information in such power supplies. The Bit Error Rate (BER) is measured for different power of the transmitted signal.
{"title":"Data transmission over an inverter-fed induction machine","authors":"N. Ginot, C. Batard, M. Mannah, M. Machmoum","doi":"10.1109/POWERENG.2011.6036529","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036529","url":null,"abstract":"The use of electrical power supply networks as a communication medium is currently under development. For example, Power Line Communication (PLC) allows nowadays interconnecting high-speed multimedia equipments while using the electrical mains supply. This paper revolves around this theme, but is purely dedicated to the Pulse Width Modulation (PWM) electrical network. The PWM power supplies are used in industrial applications such as motor drive application. The work in progress is at the boundary of two distinct fields: communication and high currents. Firstly, we underline the limits of functioning of the PLC modems on a PWM power supply. Subsequently, a filtering solution employing passive filters is discussed. Finally, the development of a new modem dedicated to PWM power supply is presented and inserted in a motor drive application. Experimental results show the ability of the modem to transmit high-speed information in such power supplies. The Bit Error Rate (BER) is measured for different power of the transmitted signal.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129438536","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036506
S. Benelghali, F. Mekri, M. Benbouzid, J. Charpentier
Multiphase generators seems to be an interesting solution for variable-speed drive applications and particularly attractive for renewable energy generation. In this context, the performance of a five-phase permanent magnet synchronous generator are evaluated within a marine current turbine and compared to a classical three-phase generator. For both topologies, a robust nonlinear control strategy, namely high-order sliding mode control, is adopted. Hence, the generators performances are analyzed, during open-circuit faults, and conclusions are derived regarding multiphase generators key features marine applications.
{"title":"Performance comparison of three — and five-phase permanent magnet generators for marine current turbine applications under open-circuit faults","authors":"S. Benelghali, F. Mekri, M. Benbouzid, J. Charpentier","doi":"10.1109/POWERENG.2011.6036506","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036506","url":null,"abstract":"Multiphase generators seems to be an interesting solution for variable-speed drive applications and particularly attractive for renewable energy generation. In this context, the performance of a five-phase permanent magnet synchronous generator are evaluated within a marine current turbine and compared to a classical three-phase generator. For both topologies, a robust nonlinear control strategy, namely high-order sliding mode control, is adopted. Hence, the generators performances are analyzed, during open-circuit faults, and conclusions are derived regarding multiphase generators key features marine applications.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131329697","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036511
Xiangjun Li, A. Dwivedi, Xinghuo Yu
Cascading failure in power networks is studied considering power flow limit on each line. The concept of correlation of lines in power grids is proposed. It explains the interaction between lines during cascading failure. An algorithm which calculates the correlated lines in a cascading failure is developed based on the DC power flow model. Computation is carried out on an IEEE 14-bus system. The results verify the significance of the concept and the algorithm.
{"title":"Assessing cascading failure in power networks based on power line correlations","authors":"Xiangjun Li, A. Dwivedi, Xinghuo Yu","doi":"10.1109/POWERENG.2011.6036511","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036511","url":null,"abstract":"Cascading failure in power networks is studied considering power flow limit on each line. The concept of correlation of lines in power grids is proposed. It explains the interaction between lines during cascading failure. An algorithm which calculates the correlated lines in a cascading failure is developed based on the DC power flow model. Computation is carried out on an IEEE 14-bus system. The results verify the significance of the concept and the algorithm.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116500248","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036443
Constantinos Soukounis, P. Dost
As electrical energy depicts itself as a future-orientated strategy for drives used in passenger cars, it is necessary to consider the conditioning of electrical energy to be used for electrical machines. The high frequent influence to the whole power train is evaluated with a view to the electrical and mechanical components. This influence is determined in reference to a comparison between a symmetric pulse wide modulation and a stator orientated hysteretic control (bang-bang-control). As electrical drives for electric vehicles need to have a wide speed range and likewise be robust the chosen control processes are checked out by using a permanent magnetic synchronous machine (PMSM) [1, 2, 3, 4]. This also offers the opportunity of a gearless drive which by the way offers a big advantage in comparison to combustion engines. For best comparison settings the energy source is realized by an ideal voltage source. To connect these components there is an inverter which builds up three-phases and likewise a rectifier in the opposed direction with a set of IGBTs and integrated antiparallel diodes. The command signal is set by the same conditions as in an traditional car by the torque demand of the acceleration pedal.
{"title":"Influence to the electrical and mechanical sub system due to inverter control processes on a power train of electric vehicles","authors":"Constantinos Soukounis, P. Dost","doi":"10.1109/POWERENG.2011.6036443","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036443","url":null,"abstract":"As electrical energy depicts itself as a future-orientated strategy for drives used in passenger cars, it is necessary to consider the conditioning of electrical energy to be used for electrical machines. The high frequent influence to the whole power train is evaluated with a view to the electrical and mechanical components. This influence is determined in reference to a comparison between a symmetric pulse wide modulation and a stator orientated hysteretic control (bang-bang-control). As electrical drives for electric vehicles need to have a wide speed range and likewise be robust the chosen control processes are checked out by using a permanent magnetic synchronous machine (PMSM) [1, 2, 3, 4]. This also offers the opportunity of a gearless drive which by the way offers a big advantage in comparison to combustion engines. For best comparison settings the energy source is realized by an ideal voltage source. To connect these components there is an inverter which builds up three-phases and likewise a rectifier in the opposed direction with a set of IGBTs and integrated antiparallel diodes. The command signal is set by the same conditions as in an traditional car by the torque demand of the acceleration pedal.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"604 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116372914","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036475
M. Spichartz, V. Staudt, A. Steimel
The control of power-electronic laboratory test benches for academic use and for industrial research and development demands a real-time control system with high flexibility and reliability at low cost. Personal computers are an ideal basis for this kind of real-time control systems because of their high processing power at very low cost and their expandability by additional interface cards. An additional field-programmable gate array is necessary to assure the real-time ability by defining the equidistant hard real-time task including the measurement routines, the control calculations and the switching signals output. The presented control system is optimized for the use in a Modular Multilevel Converter test bench, designed as a five-level converter with a high number of inputs and outputs.
{"title":"PC-based real-time control system for power-electronic test benches with high I/O requirements","authors":"M. Spichartz, V. Staudt, A. Steimel","doi":"10.1109/POWERENG.2011.6036475","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036475","url":null,"abstract":"The control of power-electronic laboratory test benches for academic use and for industrial research and development demands a real-time control system with high flexibility and reliability at low cost. Personal computers are an ideal basis for this kind of real-time control systems because of their high processing power at very low cost and their expandability by additional interface cards. An additional field-programmable gate array is necessary to assure the real-time ability by defining the equidistant hard real-time task including the measurement routines, the control calculations and the switching signals output. The presented control system is optimized for the use in a Modular Multilevel Converter test bench, designed as a five-level converter with a high number of inputs and outputs.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126923136","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 : 2011-05-11DOI: 10.1109/POWERENG.2011.6036541
M. Mezzarobba, Luca Spangaro, A. Tessarolo
In today's power generation systems, driven by variable-speed prime movers and feeding DC or fixed-frequency grids, the output power of the alternator needs to be rectified. The presence of output rectifier bridges causes a significant distortion of phase currents. This paper investigates the role played by rotor damper circuits in limiting the effects of such distortion. The investigation is extended to the case of multiphase alternator arrangements suitable for supplying a different number of output rectifiers. The study is conducted through tests on an alternator prototype which has been operated with two kinds of rotors, one with and the other without damper circuits. Testing results show that the influence of dampers is significant only in the case of generator three-phase winding and single output bridge.
{"title":"Experimental evaluation of damper circuit influence on the performance of multiphase synchrnounous generators feeding multiple rectifiers","authors":"M. Mezzarobba, Luca Spangaro, A. Tessarolo","doi":"10.1109/POWERENG.2011.6036541","DOIUrl":"https://doi.org/10.1109/POWERENG.2011.6036541","url":null,"abstract":"In today's power generation systems, driven by variable-speed prime movers and feeding DC or fixed-frequency grids, the output power of the alternator needs to be rectified. The presence of output rectifier bridges causes a significant distortion of phase currents. This paper investigates the role played by rotor damper circuits in limiting the effects of such distortion. The investigation is extended to the case of multiphase alternator arrangements suitable for supplying a different number of output rectifiers. The study is conducted through tests on an alternator prototype which has been operated with two kinds of rotors, one with and the other without damper circuits. Testing results show that the influence of dampers is significant only in the case of generator three-phase winding and single output bridge.","PeriodicalId":166144,"journal":{"name":"2011 International Conference on Power Engineering, Energy and Electrical Drives","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125840984","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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