Pub Date : 2017-08-01DOI: 10.1109/UPEC.2017.8231873
Arshad, A. Nekahi, S. McMeekin, M. Farzaneh
Chemical changes along the surface of silicone rubber material due to partial arcs and dry band arcing were studied in this paper. Rectangular samples of silicone rubber were used for experiments and pollution was applied using the modified solid layer method based on IEC 60507. All tests were carried out in a climate chamber having temperature, humidity and fog rate control. Clean bands of 1 cm were inserted at the high voltage end, ground end and middle part of the sample. The heat generated due to partial arcs along clean and dry bands causes chemical changes decreasing hydrophobicity of silicone rubber insulators. These surface modifications were analysed using Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy. Ageing analysis was carried out after 24 hour of the high voltage application, to provide sufficient relaxation time for hydrophobicity recovery. After dry band arcing, hydroxyl group (OH) were formed on the insulator surface while the hydrophobic group (CH) content was reduced. The results of this study will further our knowledge regarding the performance of polymeric insulators in humid and contaminated conditions.
{"title":"Ageing and degradation of silicone rubber insulators due to dry band arcing under contaminated conditions","authors":"Arshad, A. Nekahi, S. McMeekin, M. Farzaneh","doi":"10.1109/UPEC.2017.8231873","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231873","url":null,"abstract":"Chemical changes along the surface of silicone rubber material due to partial arcs and dry band arcing were studied in this paper. Rectangular samples of silicone rubber were used for experiments and pollution was applied using the modified solid layer method based on IEC 60507. All tests were carried out in a climate chamber having temperature, humidity and fog rate control. Clean bands of 1 cm were inserted at the high voltage end, ground end and middle part of the sample. The heat generated due to partial arcs along clean and dry bands causes chemical changes decreasing hydrophobicity of silicone rubber insulators. These surface modifications were analysed using Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy. Ageing analysis was carried out after 24 hour of the high voltage application, to provide sufficient relaxation time for hydrophobicity recovery. After dry band arcing, hydroxyl group (OH) were formed on the insulator surface while the hydrophobic group (CH) content was reduced. The results of this study will further our knowledge regarding the performance of polymeric insulators in humid and contaminated conditions.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131544975","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231997
Georgios A. Barzegkar-Ntovom, O. Ceylan, T. Papadopoulos
In this paper, the performance of different optimization techniques is evaluated for the estimation of dynamic load model parameters. Two categories of methods are considered: the nonlinear least-squares-based and the population-based. The accuracy of the optimization methods is assessed by applying Monte Carlo simulations using artificially created distorted data. In order to represent different real-world conditions, the performance of the methods is evaluated considering different levels of signal-to-noise ratio. The findings of this paper indicate that similar results are obtained by the different techniques examined and verify the validity of the optimization methods for parameter estimation of dynamic load models.
{"title":"Optimization techniques for parameter estimation of dynamic load models","authors":"Georgios A. Barzegkar-Ntovom, O. Ceylan, T. Papadopoulos","doi":"10.1109/UPEC.2017.8231997","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231997","url":null,"abstract":"In this paper, the performance of different optimization techniques is evaluated for the estimation of dynamic load model parameters. Two categories of methods are considered: the nonlinear least-squares-based and the population-based. The accuracy of the optimization methods is assessed by applying Monte Carlo simulations using artificially created distorted data. In order to represent different real-world conditions, the performance of the methods is evaluated considering different levels of signal-to-noise ratio. The findings of this paper indicate that similar results are obtained by the different techniques examined and verify the validity of the optimization methods for parameter estimation of dynamic load models.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114655469","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231902
A. Bouhouras, K. Chatzisavvas, E. Panagiotou, N. Poulakis, Constantinos Parisses, Georgios C. Christoforidis
This paper examines the development of load signatures based on odd order harmonic current vectors. A measurement setup is developed, and measurements concerning stand-alone and combined operation of several appliances in steady state have been performed using the fundamental voltage phase angle as the angular reference. The proposed load signatures consist of the first three harmonic order currents and each one of them is considered a vector quantity. An alternative formulation that considers only the projections of these vectors on the x-axis is also proposed in order to simplify the load signatures structure. The disaggregation scheme regarding the NILM approach assumes that the contribution of each appliance's harmonic current to the aggregated one, under simultaneous operation of specific appliances, is linear and results by summation of the respective components. Results indicate that the accuracy of this approach is higher when harmonic currents are treated as vectors and their phase angle is taken into account in the computations. The proposed load signature formulation is simple, the linear approach for the disaggregation scheme is kept regardless the harmonic current vectors consideration and the results seem to be more accurate.
{"title":"Load signatures development via harmonic current vectors","authors":"A. Bouhouras, K. Chatzisavvas, E. Panagiotou, N. Poulakis, Constantinos Parisses, Georgios C. Christoforidis","doi":"10.1109/UPEC.2017.8231902","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231902","url":null,"abstract":"This paper examines the development of load signatures based on odd order harmonic current vectors. A measurement setup is developed, and measurements concerning stand-alone and combined operation of several appliances in steady state have been performed using the fundamental voltage phase angle as the angular reference. The proposed load signatures consist of the first three harmonic order currents and each one of them is considered a vector quantity. An alternative formulation that considers only the projections of these vectors on the x-axis is also proposed in order to simplify the load signatures structure. The disaggregation scheme regarding the NILM approach assumes that the contribution of each appliance's harmonic current to the aggregated one, under simultaneous operation of specific appliances, is linear and results by summation of the respective components. Results indicate that the accuracy of this approach is higher when harmonic currents are treated as vectors and their phase angle is taken into account in the computations. The proposed load signature formulation is simple, the linear approach for the disaggregation scheme is kept regardless the harmonic current vectors consideration and the results seem to be more accurate.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"174 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115286744","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231885
Simon De Zutter, J. D. De Kooning, Arash E. Samani, Jens Baetens, L. Vandevelde
This paper proposes the use of an active yaw system to protect small and medium wind turbines in the high wind zone from overloading. The active yaw system turns the rotor partially out of the wind to decrease the turbine power. The dependency of the power on the yaw angle is modeled by the third power of the cosine of the yaw angle. A proper controller is configured based on on-off control of the yaw mechanism. A supplementary rotor speed control is required to avoid static instability. The proposed power limitation strategy is simulated in dynamic situations. The step response simulations show that a yaw rate of the order of 3°/s is required to properly limit the power. Simulations using a realistic wind profile demonstrate that the system can cope with the fluctuating nature of the wind.
{"title":"Modeling of active yaw systems for small and medium wind turbines","authors":"Simon De Zutter, J. D. De Kooning, Arash E. Samani, Jens Baetens, L. Vandevelde","doi":"10.1109/UPEC.2017.8231885","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231885","url":null,"abstract":"This paper proposes the use of an active yaw system to protect small and medium wind turbines in the high wind zone from overloading. The active yaw system turns the rotor partially out of the wind to decrease the turbine power. The dependency of the power on the yaw angle is modeled by the third power of the cosine of the yaw angle. A proper controller is configured based on on-off control of the yaw mechanism. A supplementary rotor speed control is required to avoid static instability. The proposed power limitation strategy is simulated in dynamic situations. The step response simulations show that a yaw rate of the order of 3°/s is required to properly limit the power. Simulations using a realistic wind profile demonstrate that the system can cope with the fluctuating nature of the wind.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125521570","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231941
W. H. Kazeza, S. Daniel Chowdhury
This paper is based on the performance of the Brushless Direct Current Motor (BLDCM) centrifugal pump set fed by wide input voltage solar photovoltaic (PV) generator using Quasi Z Source Inverter (QZSI). The aim of this paper is to develop water pumping control loops enabling the system load line operating point to track and match that of the centrifugal pump best efficiency point (BEP) along the Head Flow rate curve (HQ curve). In this way, the pumping scheme operates at optimal points and achieves highest allowable centrifugal pump efficiency with long-term safe operation. Considering the wide input voltage range of solar photovoltaic (PV) power generator, this paper presents a novel BLDCM adjustable speed drive to ensure continuous water pumping at the highest allowable efficiency. The designed water pumping system has been modeled and studied in Matlab Simulink. It was found that throughout the steady state operation under highly variable solar PV generated power, the system load line operating point was always in the vicinity of that of the centrifugal pumps BEP. The recorded best efficiency point tracking (BEPT) was found to be 96%. Presented result means that with the proposed BEPT mapping algorithm, the power drawn from the PV generator is optimal for the intended usage of water transport in a context of highly variable supplied power.
{"title":"Three phase Quasi Z source inverter fed solar PV wide input voltage range for BLDCM pumps","authors":"W. H. Kazeza, S. Daniel Chowdhury","doi":"10.1109/UPEC.2017.8231941","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231941","url":null,"abstract":"This paper is based on the performance of the Brushless Direct Current Motor (BLDCM) centrifugal pump set fed by wide input voltage solar photovoltaic (PV) generator using Quasi Z Source Inverter (QZSI). The aim of this paper is to develop water pumping control loops enabling the system load line operating point to track and match that of the centrifugal pump best efficiency point (BEP) along the Head Flow rate curve (HQ curve). In this way, the pumping scheme operates at optimal points and achieves highest allowable centrifugal pump efficiency with long-term safe operation. Considering the wide input voltage range of solar photovoltaic (PV) power generator, this paper presents a novel BLDCM adjustable speed drive to ensure continuous water pumping at the highest allowable efficiency. The designed water pumping system has been modeled and studied in Matlab Simulink. It was found that throughout the steady state operation under highly variable solar PV generated power, the system load line operating point was always in the vicinity of that of the centrifugal pumps BEP. The recorded best efficiency point tracking (BEPT) was found to be 96%. Presented result means that with the proposed BEPT mapping algorithm, the power drawn from the PV generator is optimal for the intended usage of water transport in a context of highly variable supplied power.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128214898","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231911
Glenn O'Reilly, Joseph Kearney, J. Lawler, T. Looby
The objective of the paper is to develop a robust and reliable method to pinpoint submarine cable faults. Submarine cables have existed for over 100 years but there is still no single method used to determine the precise location of a submarine cable fault. The various methods used to pinpoint cable faults, both submarine and non-submarine were researched and investigated to produce a method which would accurately pinpoint submarine cable faults. From this, the idea of a hydrophone string was derived from a non-submarine pinpointing method currently used. The hydrophone string was tested and it accurately pinpointed the location of the cable fault.
{"title":"Design of an underwater cable fault location device to precisely locate submarine cable faults","authors":"Glenn O'Reilly, Joseph Kearney, J. Lawler, T. Looby","doi":"10.1109/UPEC.2017.8231911","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231911","url":null,"abstract":"The objective of the paper is to develop a robust and reliable method to pinpoint submarine cable faults. Submarine cables have existed for over 100 years but there is still no single method used to determine the precise location of a submarine cable fault. The various methods used to pinpoint cable faults, both submarine and non-submarine were researched and investigated to produce a method which would accurately pinpoint submarine cable faults. From this, the idea of a hydrophone string was derived from a non-submarine pinpointing method currently used. The hydrophone string was tested and it accurately pinpointed the location of the cable fault.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129589000","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231969
R. Gondo, S. Ito, Kenta Iifuru, N. Nagaoka
A cost effective circuit to charge and discharge secondary batteries by an arbitrary current waveform is developed for investigating deterioration characteristics of the batteries. A charging management integrated circuit (IC) is employed for controlling both charging and discharging because there are few ICs to control the discharging of the batteries. The circuit configuration with the common ICs reduces the cost of the test system. This system can easily deteriorate the secondary batteries by a computer controlled current waveform. The developed circuit enables to charge/discharge different kinds of batteries such as series-connected lithium-ion (Li-ion), nickel metal hydride (Ni-MH) and lead acid (Pb) batteries with nominal voltages from 2 to 9 V.
{"title":"Development of multi-type secondary-battery charger/discharger by arbitrary current waveform","authors":"R. Gondo, S. Ito, Kenta Iifuru, N. Nagaoka","doi":"10.1109/UPEC.2017.8231969","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231969","url":null,"abstract":"A cost effective circuit to charge and discharge secondary batteries by an arbitrary current waveform is developed for investigating deterioration characteristics of the batteries. A charging management integrated circuit (IC) is employed for controlling both charging and discharging because there are few ICs to control the discharging of the batteries. The circuit configuration with the common ICs reduces the cost of the test system. This system can easily deteriorate the secondary batteries by a computer controlled current waveform. The developed circuit enables to charge/discharge different kinds of batteries such as series-connected lithium-ion (Li-ion), nickel metal hydride (Ni-MH) and lead acid (Pb) batteries with nominal voltages from 2 to 9 V.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130574929","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231950
A. Bottenberg, J. Knockaert, J. Desmet
The proposition for this study is to assess how much simulation results can differ from real measurements on the implementation of a control strategy for a grid-connected PV inverter. The system is simulated in Matlab/Simulink and experimentally evaluated on a real low-voltage distribution grid. The PV inverter is implemented using a power-hardware-in-the-loop platform running the control algorithm. The influence of linear and nonlinear loads and the interaction with another distributed energy resource operating on the same grid is quantified both in simulation and in the measurements. Finally, the control strategy is applied and the results for simulation and experimental setup are shown.
{"title":"Comparing accuracy and runtime of simulation to the measurements in a real grid for the control of a grid-connected PV inverter","authors":"A. Bottenberg, J. Knockaert, J. Desmet","doi":"10.1109/UPEC.2017.8231950","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231950","url":null,"abstract":"The proposition for this study is to assess how much simulation results can differ from real measurements on the implementation of a control strategy for a grid-connected PV inverter. The system is simulated in Matlab/Simulink and experimentally evaluated on a real low-voltage distribution grid. The PV inverter is implemented using a power-hardware-in-the-loop platform running the control algorithm. The influence of linear and nonlinear loads and the interaction with another distributed energy resource operating on the same grid is quantified both in simulation and in the measurements. Finally, the control strategy is applied and the results for simulation and experimental setup are shown.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130816484","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231972
C. Marouchos, G. Putrus, M. Darwish, F. Paterakis
The Switched Capacitor (SC) Circuit is investigated in this paper as a Solid-State Fault Current Limiter and interrupting device (FCLID) with power factor correction suitable for low-voltage distribution networks. It was applied so far successfully as a power factor and harmonic current compensator and as a Switched Capacitor Circuit inverter. In this application it is inserted in series with the supply line, providing both power factor correction and limitation of the current to a pre-set value in the event of a fault. Interruption of the fault is also possible by setting both semiconductor switches in the off state. Overvoltage is present in SC Circuits and they appear across both the passive and active components. The problem can be alleviated by optimising the system operation and system components.
{"title":"An investigation of the switched-capacitor circuit as a solid-state fault current limiting and interrupting device (FCLID) with power factor correction suitable for low-voltage distribution networks","authors":"C. Marouchos, G. Putrus, M. Darwish, F. Paterakis","doi":"10.1109/UPEC.2017.8231972","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231972","url":null,"abstract":"The Switched Capacitor (SC) Circuit is investigated in this paper as a Solid-State Fault Current Limiter and interrupting device (FCLID) with power factor correction suitable for low-voltage distribution networks. It was applied so far successfully as a power factor and harmonic current compensator and as a Switched Capacitor Circuit inverter. In this application it is inserted in series with the supply line, providing both power factor correction and limitation of the current to a pre-set value in the event of a fault. Interruption of the fault is also possible by setting both semiconductor switches in the off state. Overvoltage is present in SC Circuits and they appear across both the passive and active components. The problem can be alleviated by optimising the system operation and system components.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130832254","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 : 2017-08-01DOI: 10.1109/UPEC.2017.8231884
Patrick Rumpelt, R. Fritsche, B. Bakija, F. Jenau
Ester-based insulating liquids are increasingly used in transformers. Due to their short operating times, the exact understanding of their aging behaviour is missing. The aim of the presented investigations is to characterise the ester-based insulating fluids with existing diagnostic methods after a long time, where the insulating fluids impinge with simultaneous electrical and thermal stress.
{"title":"Long-term investigations of partial discharge and gassing behavior of ester-based insulating oils for a heated oil gap","authors":"Patrick Rumpelt, R. Fritsche, B. Bakija, F. Jenau","doi":"10.1109/UPEC.2017.8231884","DOIUrl":"https://doi.org/10.1109/UPEC.2017.8231884","url":null,"abstract":"Ester-based insulating liquids are increasingly used in transformers. Due to their short operating times, the exact understanding of their aging behaviour is missing. The aim of the presented investigations is to characterise the ester-based insulating fluids with existing diagnostic methods after a long time, where the insulating fluids impinge with simultaneous electrical and thermal stress.","PeriodicalId":272049,"journal":{"name":"2017 52nd International Universities Power Engineering Conference (UPEC)","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126710003","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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