Pub Date : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330984
Ryan O. Berriel, A. Bouscayrol, P. Delarue, C. Brocart
This paper analyses the impact of mechanical braking strategy in the energy consumption of a subway. For this purpose, a dynamical model and control of the subway are developed. Furthermore, simulations are carried out for different mechanical braking strategies. A difference of approximately 21% on energy consumption can be saved by energy recovery for the considered trip.
{"title":"Mechanical Braking Strategy Impact on Energy Consumption of a Subway","authors":"Ryan O. Berriel, A. Bouscayrol, P. Delarue, C. Brocart","doi":"10.1109/VPPC49601.2020.9330984","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330984","url":null,"abstract":"This paper analyses the impact of mechanical braking strategy in the energy consumption of a subway. For this purpose, a dynamical model and control of the subway are developed. Furthermore, simulations are carried out for different mechanical braking strategies. A difference of approximately 21% on energy consumption can be saved by energy recovery for the considered trip.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"31 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77505310","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330927
Rabih Al Haddad, Hussein Basma, C. Mansour
With the current conventional control strategies applied to the Heat Pump system in battery-electric buses, its driving range is being considerably reduced, particularly in cold weather conditions. This study proposes a genetic algorithm-based control strategy that optimizes the coefficient of performance of the HP system to decrease its energy consumption and maximize the driving range. The consumption results of the proposed controller are compared to those of the default controller used on the HP system currently implemented in electric buses. Results show a reduction in HP’s energy consumption by up to 36% under transient and steady-state conditions.
{"title":"Genetic Algorithm Control Strategy for Heat Pump System in Battery Electric Buses","authors":"Rabih Al Haddad, Hussein Basma, C. Mansour","doi":"10.1109/VPPC49601.2020.9330927","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330927","url":null,"abstract":"With the current conventional control strategies applied to the Heat Pump system in battery-electric buses, its driving range is being considerably reduced, particularly in cold weather conditions. This study proposes a genetic algorithm-based control strategy that optimizes the coefficient of performance of the HP system to decrease its energy consumption and maximize the driving range. The consumption results of the proposed controller are compared to those of the default controller used on the HP system currently implemented in electric buses. Results show a reduction in HP’s energy consumption by up to 36% under transient and steady-state conditions.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"754 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77521378","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330879
M. Porru, M. Pisano, A. Serpi, F. Pilo
This paper presents the commercial state-of-the-art of electric leisure boats. Particularly, several kinds of electric propulsion systems for electric and full electric boats are considered and reviewed, by investigating the attendees of some of the most important international boat shows. The analysis highlights that the market proposes electric propulsion systems which cover a wide range of boats in terms of kinds, dimensions, and scopes. Similarly, a number of full electric boats are also available on the market, promising eco-friendly, efficient, exciting and quietly sailing experiences. The present overview focuses on motor and battery sizes, as well as on expected performance and optional systems, such as range extenders and hydrofoil systems.
{"title":"Electrification of Leisure Boats: a commercial State-of-the-Art","authors":"M. Porru, M. Pisano, A. Serpi, F. Pilo","doi":"10.1109/VPPC49601.2020.9330879","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330879","url":null,"abstract":"This paper presents the commercial state-of-the-art of electric leisure boats. Particularly, several kinds of electric propulsion systems for electric and full electric boats are considered and reviewed, by investigating the attendees of some of the most important international boat shows. The analysis highlights that the market proposes electric propulsion systems which cover a wide range of boats in terms of kinds, dimensions, and scopes. Similarly, a number of full electric boats are also available on the market, promising eco-friendly, efficient, exciting and quietly sailing experiences. The present overview focuses on motor and battery sizes, as well as on expected performance and optional systems, such as range extenders and hydrofoil systems.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"15 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82544026","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330890
A. Fernandez-Hernandez, A. Garcia‐Bediaga, I. Villar, G. Abad
Volumetric and gravimetric power density improvements are one of the main objectives in More Electric Aircraft (MEA). The number of variables which influence both parameters is wide, and its impact is difficult to predict. Also, there are many applications in which DAB converter is employed, as energy-storage systems (ESS) or power flow regulation among DC buses. The selection of the most appropriate modulation is a design challenge. Therefore, this paper presents the analytical equations of switching, RMS and AVG currents for different modulation methods proposed in literature for DAB converter. To this end, voltage and current waveforms through the transformer have been characterized. Afterwards, these waveforms are employed to extract the analytical equations of the currents for future power losses evaluation. Finally, PLECS simulation model have been developed to validate the analytical equations obtained in this paper for a MEA case study.
{"title":"Analytical Equations of the Currents in Dual Active Bridge Converter for More Electric Aircraft","authors":"A. Fernandez-Hernandez, A. Garcia‐Bediaga, I. Villar, G. Abad","doi":"10.1109/VPPC49601.2020.9330890","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330890","url":null,"abstract":"Volumetric and gravimetric power density improvements are one of the main objectives in More Electric Aircraft (MEA). The number of variables which influence both parameters is wide, and its impact is difficult to predict. Also, there are many applications in which DAB converter is employed, as energy-storage systems (ESS) or power flow regulation among DC buses. The selection of the most appropriate modulation is a design challenge. Therefore, this paper presents the analytical equations of switching, RMS and AVG currents for different modulation methods proposed in literature for DAB converter. To this end, voltage and current waveforms through the transformer have been characterized. Afterwards, these waveforms are employed to extract the analytical equations of the currents for future power losses evaluation. Finally, PLECS simulation model have been developed to validate the analytical equations obtained in this paper for a MEA case study.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"1 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76584907","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330875
A. Gancedo, I. El-Sayed, Peru Bidaguren, P. Arboleya
This report is based on a Master’s Thesis [1], in which a tool to calculate the thermal behavior of railway electrification systems has been developed by means of iterative calculations based on heat transfer and energy conversion equations. The calculation method is implemented in Matlab, allowing to study the temperature of overhead bare lines. The aim of this tool is to size the section of the conductors (catenary, feeder) and calculate the recovery time of the system against unexpected contingencies. The input data is obtained from RailNeos 2.0, a simulator of railway electrification systems which is able to calculate the total energy consumption of the system, taking into account the implementation of accumulation devices. This tool was developed by Lemur Research Group of the University of Oviedo and CAF Tunrkey & Engineering.
{"title":"Thermal Analysis in Railway Electrification Systems for bare conductors","authors":"A. Gancedo, I. El-Sayed, Peru Bidaguren, P. Arboleya","doi":"10.1109/VPPC49601.2020.9330875","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330875","url":null,"abstract":"This report is based on a Master’s Thesis [1], in which a tool to calculate the thermal behavior of railway electrification systems has been developed by means of iterative calculations based on heat transfer and energy conversion equations. The calculation method is implemented in Matlab, allowing to study the temperature of overhead bare lines. The aim of this tool is to size the section of the conductors (catenary, feeder) and calculate the recovery time of the system against unexpected contingencies. The input data is obtained from RailNeos 2.0, a simulator of railway electrification systems which is able to calculate the total energy consumption of the system, taking into account the implementation of accumulation devices. This tool was developed by Lemur Research Group of the University of Oviedo and CAF Tunrkey & Engineering.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"31 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73391891","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330907
Manuel Pereira, P. Melo, R. Araújo
Switched reluctance machines are simple, robust, fault-tolerant and do not use permanent magnets, which makes them a strong candidate for vehicular propulsion. Despites the advantages they still suffer from high torque pulsation and acoustic noise, which can be reduced by the controller. In this paper the concern is in having an advanced current control, so it is used the model predictive control (MPC). This requires an accurate model to estimate the future behavior of current and the back-electromotive force (emf) signal is essential. As this signal cannot be directly calculated or measured it is proposed a new algorithm to calculate its estimation in real time. The algorithm is easy to implement and the numerical results show the accuracy of the method, which permits a very low current estimation error in the MPC framework.
{"title":"A Back-EMF Estimation Method for a Switched Reluctance Motor using Model Predictive Control","authors":"Manuel Pereira, P. Melo, R. Araújo","doi":"10.1109/VPPC49601.2020.9330907","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330907","url":null,"abstract":"Switched reluctance machines are simple, robust, fault-tolerant and do not use permanent magnets, which makes them a strong candidate for vehicular propulsion. Despites the advantages they still suffer from high torque pulsation and acoustic noise, which can be reduced by the controller. In this paper the concern is in having an advanced current control, so it is used the model predictive control (MPC). This requires an accurate model to estimate the future behavior of current and the back-electromotive force (emf) signal is essential. As this signal cannot be directly calculated or measured it is proposed a new algorithm to calculate its estimation in real time. The algorithm is easy to implement and the numerical results show the accuracy of the method, which permits a very low current estimation error in the MPC framework.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"17 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75291265","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330873
Christian Østergaard, Claus Kjeldsen, M. Nymand
This paper highlights how a currently available transformer equivalent circuit model incorrectly represents the transformer performance, in scenarios where both sides of the transformer are fixed to a common reference-point. A new transformer equivalent circuit model is presented which accurately predicts the transformer performance. A thorough analysis of the proposed model and a commonly used model is compared and presented. Three foil-wound and three wire-wound transformers with different turns ratio are constructed, with the purpose of evaluating the accuracy of the transformer models impedance prediction. Both models accurately predict the transformer impedance for a turns-ratio equal to one. With turns-ratios different from one, the commonly used model predicts wrong impedance, whereas the proposed model remains accurate. The error in the predicted equivalent capacitance of the measurements is between 32%-170% when using the commonly used model, while it is only 0.6%-9.8% when using the proposed model. The proposed model is therefore the only model that provides accurate impedance analysis for any turns-ratio in any operation scenario.
{"title":"Simple Equivalent Circuit Capacitance Model for Two-Winding Transformers","authors":"Christian Østergaard, Claus Kjeldsen, M. Nymand","doi":"10.1109/VPPC49601.2020.9330873","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330873","url":null,"abstract":"This paper highlights how a currently available transformer equivalent circuit model incorrectly represents the transformer performance, in scenarios where both sides of the transformer are fixed to a common reference-point. A new transformer equivalent circuit model is presented which accurately predicts the transformer performance. A thorough analysis of the proposed model and a commonly used model is compared and presented. Three foil-wound and three wire-wound transformers with different turns ratio are constructed, with the purpose of evaluating the accuracy of the transformer models impedance prediction. Both models accurately predict the transformer impedance for a turns-ratio equal to one. With turns-ratios different from one, the commonly used model predicts wrong impedance, whereas the proposed model remains accurate. The error in the predicted equivalent capacitance of the measurements is between 32%-170% when using the commonly used model, while it is only 0.6%-9.8% when using the proposed model. The proposed model is therefore the only model that provides accurate impedance analysis for any turns-ratio in any operation scenario.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"1 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79925638","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330894
M. F. Far, Marko Paakkinen, P. Cremers
Due to the concerns on increasing fossil fuel consumption and its significant negative impact on environment, many European Union countries are planning to move towards fossil-fuel-free transport system by replacing the fossil fuel buses with zero-emission electric buses. To ensure a smooth transition to electric bus solution and fast integration of these vehicles with charging infrastructure, a set of unified standards is required for charging of the electric vehicles. Different projects and committees, such as H2020 ASSURED project, have included this requirement in their working agenda during the last few years. This paper presents ASSURED and other projects activities for achieving interoperable and reliable heavy-duty electric vehicle fleets.
{"title":"A Framework for Charging Standardisation of Electric Buses in Europe","authors":"M. F. Far, Marko Paakkinen, P. Cremers","doi":"10.1109/VPPC49601.2020.9330894","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330894","url":null,"abstract":"Due to the concerns on increasing fossil fuel consumption and its significant negative impact on environment, many European Union countries are planning to move towards fossil-fuel-free transport system by replacing the fossil fuel buses with zero-emission electric buses. To ensure a smooth transition to electric bus solution and fast integration of these vehicles with charging infrastructure, a set of unified standards is required for charging of the electric vehicles. Different projects and committees, such as H2020 ASSURED project, have included this requirement in their working agenda during the last few years. This paper presents ASSURED and other projects activities for achieving interoperable and reliable heavy-duty electric vehicle fleets.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"129 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76706578","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330865
Isabel Carrilero Borbujo, P. Pereirinha, Jorge Alonso del Valle, M. G. Vega, D. A. González, J. Pérez
The European Union is pushing forward its European Green Deal where sustainable mobility is one of the main areas of interest, especially after the COVID-19 crisis. The role of battery electric buses (BEBs) in public transit is key to achieve sustainable mobility and to reduce city pollution and greenhouse gas emissions and, therefore, global warming. Standardization plays a key role to ensure the deployment of a safe, cost effective, energy efficient, sustainable BEBs fleet. Standardization of components, interoperability, generalized recharge possibility, and even the possibility of using the BEBs as controllable loads, with energy storage that can be returned to the grid, must be done. This paper presents the most relevant legislation at European level, the International and European standardization outline in the field of BEBs, and the most important standardization activities going on. It gives references to deal with the very high number of standards relevant for the BEBs and the related activities that are in constant update, from different standardization entities.
{"title":"International and European Legislation and Standards for Battery Electric Buses","authors":"Isabel Carrilero Borbujo, P. Pereirinha, Jorge Alonso del Valle, M. G. Vega, D. A. González, J. Pérez","doi":"10.1109/VPPC49601.2020.9330865","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330865","url":null,"abstract":"The European Union is pushing forward its European Green Deal where sustainable mobility is one of the main areas of interest, especially after the COVID-19 crisis. The role of battery electric buses (BEBs) in public transit is key to achieve sustainable mobility and to reduce city pollution and greenhouse gas emissions and, therefore, global warming. Standardization plays a key role to ensure the deployment of a safe, cost effective, energy efficient, sustainable BEBs fleet. Standardization of components, interoperability, generalized recharge possibility, and even the possibility of using the BEBs as controllable loads, with energy storage that can be returned to the grid, must be done. This paper presents the most relevant legislation at European level, the International and European standardization outline in the field of BEBs, and the most important standardization activities going on. It gives references to deal with the very high number of standards relevant for the BEBs and the related activities that are in constant update, from different standardization entities.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"192 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76945459","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 : 2020-11-01DOI: 10.1109/VPPC49601.2020.9330841
Anand Ganesan, S. Gros, Nikolce Murgovski, Chih Feng Lee, M. Sivertsson
This paper presents a model predictive control (MPC) based supervisory power-split control strategy, which optimises fuel and energy consumption in Hybrid Electric Vehicles (HEVs) by incorporating powertrain actuator dynamic models. In HEVs, while distributing the driver demand to the powertrain actuators, a standard approach is to approximate the actuator energy conversion dynamics with steady-state maps, which leads to sub-optimal control policy and increased fuel & energy consumption, especially for a driving mission with high transient demands. To address this shortfall, the control strategy proposed in this paper explicitly integrates an experimentally validated dynamic model of gasoline internal combustion engine (ICE) into an MPC based power-split controller. The proposed strategy is validated in a parallel HEV platform, where the sensitivity of the HEV energy consumption w.r.t. its actuator dynamics and the transients in its load demands, is also established. The results enable an understanding of the energy saving potential in HEVs that supports the inclusion of actuator dynamic models in optimal power-split controllers and it also establishes that the proposed control strategy realises higher energy and fuel savings in HEVs.
{"title":"Effect of Engine Dynamics on Optimal Power-Split Control Strategies in Hybrid Electric Vehicles","authors":"Anand Ganesan, S. Gros, Nikolce Murgovski, Chih Feng Lee, M. Sivertsson","doi":"10.1109/VPPC49601.2020.9330841","DOIUrl":"https://doi.org/10.1109/VPPC49601.2020.9330841","url":null,"abstract":"This paper presents a model predictive control (MPC) based supervisory power-split control strategy, which optimises fuel and energy consumption in Hybrid Electric Vehicles (HEVs) by incorporating powertrain actuator dynamic models. In HEVs, while distributing the driver demand to the powertrain actuators, a standard approach is to approximate the actuator energy conversion dynamics with steady-state maps, which leads to sub-optimal control policy and increased fuel & energy consumption, especially for a driving mission with high transient demands. To address this shortfall, the control strategy proposed in this paper explicitly integrates an experimentally validated dynamic model of gasoline internal combustion engine (ICE) into an MPC based power-split controller. The proposed strategy is validated in a parallel HEV platform, where the sensitivity of the HEV energy consumption w.r.t. its actuator dynamics and the transients in its load demands, is also established. The results enable an understanding of the energy saving potential in HEVs that supports the inclusion of actuator dynamic models in optimal power-split controllers and it also establishes that the proposed control strategy realises higher energy and fuel savings in HEVs.","PeriodicalId":6851,"journal":{"name":"2020 IEEE Vehicle Power and Propulsion Conference (VPPC)","volume":"17 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81968797","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：