Pub Date : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5348024
A. Kiprakis, A. Nambiar, D. Forehand, A. Wallace
This paper describes a modelling framework developed in Matlab/Simulink that has been used to study, analyse and improve the network integration of Wave Energy Converters (WECs). It presents and discusses a generic, time domain, resource-to-wire model that can be used to explore the effects of: increased device numbers, array size and physical positioning; and the adjustment of control parameters. The three-dimensional wave field is modelled as non-stationary, with statistical characteristics that are extracted from measured wave elevation time series to simulate increasingly realistic sea conditions. Each heaving buoy has high-pressure oil power take off with on-board energy storage, driving Doubly Fed Induction Generators (DFIGs). The results obtained from simulations using this model are used to demonstrate the overall effects of storage on real power production, and the effects of imaginary power control on network voltage profile. The opportunities for improved network integration are identified and discussed.
{"title":"Modelling arrays of wave energy converters connected to weak rural electricity networks","authors":"A. Kiprakis, A. Nambiar, D. Forehand, A. Wallace","doi":"10.1109/SUPERGEN.2009.5348024","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5348024","url":null,"abstract":"This paper describes a modelling framework developed in Matlab/Simulink that has been used to study, analyse and improve the network integration of Wave Energy Converters (WECs). It presents and discusses a generic, time domain, resource-to-wire model that can be used to explore the effects of: increased device numbers, array size and physical positioning; and the adjustment of control parameters. The three-dimensional wave field is modelled as non-stationary, with statistical characteristics that are extracted from measured wave elevation time series to simulate increasingly realistic sea conditions. Each heaving buoy has high-pressure oil power take off with on-board energy storage, driving Doubly Fed Induction Generators (DFIGs). The results obtained from simulations using this model are used to demonstrate the overall effects of storage on real power production, and the effects of imaginary power control on network voltage profile. The opportunities for improved network integration are identified and discussed.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114170125","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5348330
Liu Yan-cheng, W. Chuan, Wen Yuan-quan, Cheng Peng
In order to analyze the quantified relationship between network time-delay and generators extra power output in NCS (Networked Control System), a NCS quantizer was designed by researching DTC-SVPWM (Direct Torque Control-Space Vector Pulse Width Modulation) of PMSM (Permanent Magnet Synchronous Motor) on a railway ferry. The paper deduced time delay-power association equation which was induced by senor data transportation delay to quantify the relationship between time-delay and generators extra power output. A C#.NET program was run. The simulation result indicates, it is significant for electrical propulsion ship to reduce network time-delay from the perspective of energy saving.
{"title":"Quantified energy saving analysis of PMSM networked control system","authors":"Liu Yan-cheng, W. Chuan, Wen Yuan-quan, Cheng Peng","doi":"10.1109/SUPERGEN.2009.5348330","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5348330","url":null,"abstract":"In order to analyze the quantified relationship between network time-delay and generators extra power output in NCS (Networked Control System), a NCS quantizer was designed by researching DTC-SVPWM (Direct Torque Control-Space Vector Pulse Width Modulation) of PMSM (Permanent Magnet Synchronous Motor) on a railway ferry. The paper deduced time delay-power association equation which was induced by senor data transportation delay to quantify the relationship between time-delay and generators extra power output. A C#.NET program was run. The simulation result indicates, it is significant for electrical propulsion ship to reduce network time-delay from the perspective of energy saving.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116254545","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5348247
M. R. Aghaebrahimi, M. Amiri, S. Zahiri
The Optimal sizing and placement of distributed generators has received considerable attention from researchers recently. An Immune Algorithm (IA) based optimization approach for solving the distributed generation (DG) placement problem is proposed in this paper. In the distributed generation placement problem, practical DG operating constraints including: load profiles, feeder capacities and allowable voltage limits are all considered while the investment cost, power or energy losses and voltage profile are optimized. In the proposed method, objective function (power losses) and constraints (bus voltage limits and line current limits) are represented as antigens. Through the genetic evolution, an antibody that most fits the antigen becomes the solution. In this IA computation, an affinity calculation process is also embedded to guarantee the diversity. The process stagnation can thus be prevented better.
{"title":"An immune-based optimization method for distributed generation placement in order to minimize power losses","authors":"M. R. Aghaebrahimi, M. Amiri, S. Zahiri","doi":"10.1109/SUPERGEN.2009.5348247","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5348247","url":null,"abstract":"The Optimal sizing and placement of distributed generators has received considerable attention from researchers recently. An Immune Algorithm (IA) based optimization approach for solving the distributed generation (DG) placement problem is proposed in this paper. In the distributed generation placement problem, practical DG operating constraints including: load profiles, feeder capacities and allowable voltage limits are all considered while the investment cost, power or energy losses and voltage profile are optimized. In the proposed method, objective function (power losses) and constraints (bus voltage limits and line current limits) are represented as antigens. Through the genetic evolution, an antibody that most fits the antigen becomes the solution. In this IA computation, an affinity calculation process is also embedded to guarantee the diversity. The process stagnation can thus be prevented better.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115318933","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5347990
Zhiguo Tang, Chaojun Tang, P. Ma, X. Xing, Qizhao Lin
In order to study the characteristics of a new two-stage dry feed gasifier with multi underneath nozzles jetting tangentially, numerical simulation and analysis of the gasifier for high ash melting point pulverized coal was conducted based on Fluent. A comprehensive mathematical model for simulation of pulverized coal gasifier has been developed in this paper, chemical process was described with presumed PDF mode, a gasification look-up table was built to describe the relationship between mixture fraction and the scalars of temperature, species, et al. Body fitted hexahedron mesh was adopted and k-ε RNG turbulent model was used to make a closure for turbulence equations. Dispersed phase model (DPM) were employed to describe the coupling effect between gas phase and discrete phase, and Stochastic Tracking Method (STM) were used to track turbulent dispersion of char particles and to consider the turbulent disturbance effects on particle motion on gasification process. In addition, User Defined Functions (UDF) was used to mend heterogeneous gasification reactions model, including carbon with O2, H2O, CO2 and H2. The numerical simulation and analysis of the inner velocity, temperature and species concentrations of the two-stage entrained flow coal gasifier for high ash melting point pulverized coal shown that spatial gasification reactions can be achieved in the gasifier, inner temperature grads reduce remarkably and temperature field become more even, and the key gasification parameters, such as [O]/[C] atom ratio, steam/coal ratio, were optimized through simulation, will offer reference for the further research on the gasifier for high ash melting point pulverized coal.
{"title":"Numerical simulation of a new two-stage dry feed gasifier for double-high coal","authors":"Zhiguo Tang, Chaojun Tang, P. Ma, X. Xing, Qizhao Lin","doi":"10.1109/SUPERGEN.2009.5347990","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5347990","url":null,"abstract":"In order to study the characteristics of a new two-stage dry feed gasifier with multi underneath nozzles jetting tangentially, numerical simulation and analysis of the gasifier for high ash melting point pulverized coal was conducted based on Fluent. A comprehensive mathematical model for simulation of pulverized coal gasifier has been developed in this paper, chemical process was described with presumed PDF mode, a gasification look-up table was built to describe the relationship between mixture fraction and the scalars of temperature, species, et al. Body fitted hexahedron mesh was adopted and k-ε RNG turbulent model was used to make a closure for turbulence equations. Dispersed phase model (DPM) were employed to describe the coupling effect between gas phase and discrete phase, and Stochastic Tracking Method (STM) were used to track turbulent dispersion of char particles and to consider the turbulent disturbance effects on particle motion on gasification process. In addition, User Defined Functions (UDF) was used to mend heterogeneous gasification reactions model, including carbon with O2, H2O, CO2 and H2. The numerical simulation and analysis of the inner velocity, temperature and species concentrations of the two-stage entrained flow coal gasifier for high ash melting point pulverized coal shown that spatial gasification reactions can be achieved in the gasifier, inner temperature grads reduce remarkably and temperature field become more even, and the key gasification parameters, such as [O]/[C] atom ratio, steam/coal ratio, were optimized through simulation, will offer reference for the further research on the gasifier for high ash melting point pulverized coal.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115782360","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5347928
Zhang Xiaojin, Xie Xiaorong
In this paper, a new nonlinear multimass model has been developed for SSR (Subsynchronous Resonance) evaluation. This paper first gives a brief derivation of the shaft model, which is without damping, and then provides the new nonlinear modal damping model, which is the primary contribution of this paper. Following that, the integrated modal multimass model is shown and applied to the Shangdu power plant in China. Comparison between the linear multimass model and non-linear one is also presented. The details of this approach are presented, and the performance of the non-linear modal multimass model is verified with the Shangdu system through electromagnetic simulations.
{"title":"A multimass model with non-linear modal damping for SSR analysis of turbine generators","authors":"Zhang Xiaojin, Xie Xiaorong","doi":"10.1109/SUPERGEN.2009.5347928","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5347928","url":null,"abstract":"In this paper, a new nonlinear multimass model has been developed for SSR (Subsynchronous Resonance) evaluation. This paper first gives a brief derivation of the shaft model, which is without damping, and then provides the new nonlinear modal damping model, which is the primary contribution of this paper. Following that, the integrated modal multimass model is shown and applied to the Shangdu power plant in China. Comparison between the linear multimass model and non-linear one is also presented. The details of this approach are presented, and the performance of the non-linear modal multimass model is verified with the Shangdu system through electromagnetic simulations.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123776814","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5347936
Hongxia Miao, Hong-hua Wang, Yang Xu
The electric field in the arc-quenching chamber of high voltage SF6 circuit breaker has been calculated using Finite Element Method (FEM). The distributions of equal electric potential line and electric field strength have been analyzed and figured, and the main factors which affect internal insulation of the chamber have been evaluated. Moreover, the inverse problem optimizing the chamber structure has been studied. The shapes of contacts and nozzle are selected as optimization variables. The minimum of maximal electric field strength is regarded as optimized function, which provides some theoretical basis for the overall design of high voltage SF6 circuit breaker.
{"title":"The numerical calculation and optimization design of electric field for the high voltage SF6 circuit breaker arc-quenching chamber","authors":"Hongxia Miao, Hong-hua Wang, Yang Xu","doi":"10.1109/SUPERGEN.2009.5347936","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5347936","url":null,"abstract":"The electric field in the arc-quenching chamber of high voltage SF6 circuit breaker has been calculated using Finite Element Method (FEM). The distributions of equal electric potential line and electric field strength have been analyzed and figured, and the main factors which affect internal insulation of the chamber have been evaluated. Moreover, the inverse problem optimizing the chamber structure has been studied. The shapes of contacts and nozzle are selected as optimization variables. The minimum of maximal electric field strength is regarded as optimized function, which provides some theoretical basis for the overall design of high voltage SF6 circuit breaker.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121359108","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5348007
A. Yaghi, T. Hyde, A. Becker, W. Sun
A circumferentially multi-pass butt-welded P91 steel pipe, typically used for high-temperature applications in power plants, has been numerically analysed to determine residual stresses, induced by the process of welding, as well as microstructural regions in the weld, caused by thermal cycles. The finite element (FE) method has been applied to simulate residual stresses generated in the weld region and heat affected zone (HAZ). The axisymmetric FE simulation incorporates solidstate phase transformation (SSPT) by allowing for volumetric changes in steel and associated changes in yield stress due to austenitic and martensitic transformations. The thermal cycles during welding cause different microstructural regions to emerge in the vicinity of the weld metal. Columnar and equiaxed microstructural zones have been numerically modelled in the weld region of the pipe. The predicted FE microstructural regions have been corroborated by columnar and equiaxed zones that have been mapped out on a cross-sectional macro-image of the weld.
{"title":"Thermo-mechanical modelling of P91 steel weld microstructure and residual stresses in power plant pipework","authors":"A. Yaghi, T. Hyde, A. Becker, W. Sun","doi":"10.1109/SUPERGEN.2009.5348007","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5348007","url":null,"abstract":"A circumferentially multi-pass butt-welded P91 steel pipe, typically used for high-temperature applications in power plants, has been numerically analysed to determine residual stresses, induced by the process of welding, as well as microstructural regions in the weld, caused by thermal cycles. The finite element (FE) method has been applied to simulate residual stresses generated in the weld region and heat affected zone (HAZ). The axisymmetric FE simulation incorporates solidstate phase transformation (SSPT) by allowing for volumetric changes in steel and associated changes in yield stress due to austenitic and martensitic transformations. The thermal cycles during welding cause different microstructural regions to emerge in the vicinity of the weld metal. Columnar and equiaxed microstructural zones have been numerically modelled in the weld region of the pipe. The predicted FE microstructural regions have been corroborated by columnar and equiaxed zones that have been mapped out on a cross-sectional macro-image of the weld.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114275186","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5348108
J. Gao
To research the thermal parameters of solar heat pump at Tibet, this paper presents two heating systems which apply different solar collectors. The factors such as time-varying, solar collectors and different weather conditions are considered in this paper. Furthermore, according to the different operating conditions, calculation and analysis about temperatures of the systems are carried out. The comparing the calculation results of temperature distribution of room show that the systems are satisfied and the design is reasonable.
{"title":"The study of solar heat pump with different solar collectors","authors":"J. Gao","doi":"10.1109/SUPERGEN.2009.5348108","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5348108","url":null,"abstract":"To research the thermal parameters of solar heat pump at Tibet, this paper presents two heating systems which apply different solar collectors. The factors such as time-varying, solar collectors and different weather conditions are considered in this paper. Furthermore, according to the different operating conditions, calculation and analysis about temperatures of the systems are carried out. The comparing the calculation results of temperature distribution of room show that the systems are satisfied and the design is reasonable.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125121146","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5348175
Haitao Guo, Xianhui Yang, J. Xiang, S. Watson
Availability is an important performance index for wind turbines. To predict wind turbine availability, failure rate and repair rate have to be known. There are some sources of wind turbine failure data that can be used to estimate parameters of the failure rate function and the repair rate. With repair rate assumed to be constant, this paper first presents maximum likelihood estimates for failure rate, then gives a method to predict instantaneous and long term availability for wind turbines. By keeping a record of failure time for each subassembly of a wind turbine, maintenance could be more effectively targeted with more detail in terms of what is likely to fail. Failure data from a wind farm is analyzed as an example, which shows results predicted by the technique presented are close to the wind farm statistics. This work will be helpful in planning timely and cost-effective maintenance of wind turbines.
{"title":"Wind turbine availability analysis based on statistical data","authors":"Haitao Guo, Xianhui Yang, J. Xiang, S. Watson","doi":"10.1109/SUPERGEN.2009.5348175","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5348175","url":null,"abstract":"Availability is an important performance index for wind turbines. To predict wind turbine availability, failure rate and repair rate have to be known. There are some sources of wind turbine failure data that can be used to estimate parameters of the failure rate function and the repair rate. With repair rate assumed to be constant, this paper first presents maximum likelihood estimates for failure rate, then gives a method to predict instantaneous and long term availability for wind turbines. By keeping a record of failure time for each subassembly of a wind turbine, maintenance could be more effectively targeted with more detail in terms of what is likely to fail. Failure data from a wind farm is analyzed as an example, which shows results predicted by the technique presented are close to the wind farm statistics. This work will be helpful in planning timely and cost-effective maintenance of wind turbines.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125240797","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 : 2009-04-06DOI: 10.1109/SUPERGEN.2009.5347890
Anan Zhang, Honggeng Yang
A novel approach is proposed in this paper to solve multi-objective dynamic reactive power and voltage control (Volt/VAr control, VVC). The method is able to attain the Pareto-optimal solutions, based on the day-ahead load forecast, for the VVC considering reducing daily power loss, enhancing voltage profile and optimizing dispatch schedules for on-load tap changer (OLTC) and shunt capacitor switching, which will provide users more options to schedule the dynamic VVC. This approach is applied to the IEEE14 buses system and to the IEEE30 buses system, whose result shows that it has encouraging performance in dynamic reactive power control.
{"title":"Pareto-set based multi-objective dynamic reactive power and voltage control","authors":"Anan Zhang, Honggeng Yang","doi":"10.1109/SUPERGEN.2009.5347890","DOIUrl":"https://doi.org/10.1109/SUPERGEN.2009.5347890","url":null,"abstract":"A novel approach is proposed in this paper to solve multi-objective dynamic reactive power and voltage control (Volt/VAr control, VVC). The method is able to attain the Pareto-optimal solutions, based on the day-ahead load forecast, for the VVC considering reducing daily power loss, enhancing voltage profile and optimizing dispatch schedules for on-load tap changer (OLTC) and shunt capacitor switching, which will provide users more options to schedule the dynamic VVC. This approach is applied to the IEEE14 buses system and to the IEEE30 buses system, whose result shows that it has encouraging performance in dynamic reactive power control.","PeriodicalId":250585,"journal":{"name":"2009 International Conference on Sustainable Power Generation and Supply","volume":"159 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128081831","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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