Pub Date : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850545
Dan Wu, Fen Tang, J. Guerrero, J. Vasquez
In this paper, a decentralized control for coordinate both active and reactive powers is proposed for islanded microgrids. Compared with the conventional droop control strategies, the proposed control realizes decentralized power distribution among renewable energy sources (RES) and energy storage systems (ESS) according to the local source conditions. Based on bus-signaling method, the ESS is able to limit charging power by decreasing RES power generation automatically. As well, the reactive power coordinated control makes the RES units able to support reactive power in a decentralized way, which allows ESS providing for more active power availability. Moreover, the reactive power is distributed according to the apparent power capacity of each unit. The control strategy principle is simple and easy to implement without extra communication requirements. Real time hardware-in-the-loop results are presented to show the feasibility of proposed control strategy.
{"title":"Autonomous control of distributed generation and storage to coordinate P/Q sharing in islanded microgrids - An approach beyond droop control","authors":"Dan Wu, Fen Tang, J. Guerrero, J. Vasquez","doi":"10.1109/ENERGYCON.2014.6850545","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850545","url":null,"abstract":"In this paper, a decentralized control for coordinate both active and reactive powers is proposed for islanded microgrids. Compared with the conventional droop control strategies, the proposed control realizes decentralized power distribution among renewable energy sources (RES) and energy storage systems (ESS) according to the local source conditions. Based on bus-signaling method, the ESS is able to limit charging power by decreasing RES power generation automatically. As well, the reactive power coordinated control makes the RES units able to support reactive power in a decentralized way, which allows ESS providing for more active power availability. Moreover, the reactive power is distributed according to the apparent power capacity of each unit. The control strategy principle is simple and easy to implement without extra communication requirements. Real time hardware-in-the-loop results are presented to show the feasibility of proposed control strategy.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116409914","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850467
Scott Alfeld, P. Barford
Management and operation of the electrical grid in the US is handled in large part by regional authorities called Independent System Operators (ISO's). One of the key activities of an ISO is load forecasting which is critical to short-term energy trading markets and effective operation of the power grid. In this paper, we analyze load forecasts and develop methods for improving forecasts that can be used directly by ISO's or third parties. Specifically, we assess the hourly electrical load forecasts against actual load data provided by Midwest ISO over a two-year period. Residual analysis shows systematic inaccuracies in hourly forecasts that can be caused by a variety of factors including modeling errors and pumped storage in the grid. We utilize machine learning-based methods to improve forecasts over short time horizons. Our methods reduce the mean squared error of forecasts over the entire year by roughly 20%. By shortening the forecast horizon to 1 to 32 hours, we are able to improve by over 90%. These improvements can be important in operational energy market contexts, where even small differences in forecasts can lead to large swings in transmission behavior and market activity.
{"title":"Targeted residual analysis for improving electric load forecasting","authors":"Scott Alfeld, P. Barford","doi":"10.1109/ENERGYCON.2014.6850467","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850467","url":null,"abstract":"Management and operation of the electrical grid in the US is handled in large part by regional authorities called Independent System Operators (ISO's). One of the key activities of an ISO is load forecasting which is critical to short-term energy trading markets and effective operation of the power grid. In this paper, we analyze load forecasts and develop methods for improving forecasts that can be used directly by ISO's or third parties. Specifically, we assess the hourly electrical load forecasts against actual load data provided by Midwest ISO over a two-year period. Residual analysis shows systematic inaccuracies in hourly forecasts that can be caused by a variety of factors including modeling errors and pumped storage in the grid. We utilize machine learning-based methods to improve forecasts over short time horizons. Our methods reduce the mean squared error of forecasts over the entire year by roughly 20%. By shortening the forecast horizon to 1 to 32 hours, we are able to improve by over 90%. These improvements can be important in operational energy market contexts, where even small differences in forecasts can lead to large swings in transmission behavior and market activity.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114332545","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850472
Salah K. Kanaan
The safety and the availability is becoming a major concern for each Nuclear Power Plant of each nation. Any global incident can significantly affect the public opinions. All the regulatory organs including Government regulations and even private sector standards can be tremendously affected by such incidents. As efforts are made to improve the availability and safety of future plants, questions about compatibility between different codes/standards and a satisfactory level of understanding and correct implementation at the early stage of the design may arise. Power Plants management, engineering and maintenance departments must not only possess an understanding of engineering standards and applicable governmental codes, but also learn to apply them in designing, developing, testing and servicing products, processes and systems. One crucial criterion for all departments requires engineers to understand the different aspects of the links between applying standards in their projects and know the hierarchy structures behind this and to ensure a necessary equilibrium between the two concerns during the design process. This paper reviews a methodology of understanding the hierarchy connections between the industrial IEEE standards related to class 1E power systems and Regulatory guide codes of the NRC Government regulations. This will help develop modules for identifying benchmark practices and understanding the standards as early as possible in the design process. It presents the findings of an Electrical Systems and I&C department work conducted through Electrical Engineering during autumn 2013. The hierarchy presented in this work will help to enhance the use of IEEE standards and Regulatory guides in engineering and technology curricula specifically related to providing protection for the health and safety of the public.
{"title":"The state of the use of hierarchy structure between IEEE standards and Nuclear Regulatory Guides related to class 1E Power Systems","authors":"Salah K. Kanaan","doi":"10.1109/ENERGYCON.2014.6850472","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850472","url":null,"abstract":"The safety and the availability is becoming a major concern for each Nuclear Power Plant of each nation. Any global incident can significantly affect the public opinions. All the regulatory organs including Government regulations and even private sector standards can be tremendously affected by such incidents. As efforts are made to improve the availability and safety of future plants, questions about compatibility between different codes/standards and a satisfactory level of understanding and correct implementation at the early stage of the design may arise. Power Plants management, engineering and maintenance departments must not only possess an understanding of engineering standards and applicable governmental codes, but also learn to apply them in designing, developing, testing and servicing products, processes and systems. One crucial criterion for all departments requires engineers to understand the different aspects of the links between applying standards in their projects and know the hierarchy structures behind this and to ensure a necessary equilibrium between the two concerns during the design process. This paper reviews a methodology of understanding the hierarchy connections between the industrial IEEE standards related to class 1E power systems and Regulatory guide codes of the NRC Government regulations. This will help develop modules for identifying benchmark practices and understanding the standards as early as possible in the design process. It presents the findings of an Electrical Systems and I&C department work conducted through Electrical Engineering during autumn 2013. The hierarchy presented in this work will help to enhance the use of IEEE standards and Regulatory guides in engineering and technology curricula specifically related to providing protection for the health and safety of the public.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116134676","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850560
V. Calderaro, V. Galdi, G. Graditi, F. Lamberti
Due to the increasing development of Distributed Generation (DG) based on renewable energy sources (RESs), currently voltage control represents an important issue in distribution power systems. In this paper, we propose a comparison between two voltage control methods that allow obtaining the maximum available power production from wind turbines and photovoltaic systems. Both methods suppose a wind and photovoltaic plants belonging to an Independent Power Producer (IPP) able to control each RES units. The first method is based on a coordinated local control approach that takes advantage of a mixed Distribution Network (DN) sensitivity analysis; the second one is based on a cooperation of data transfer between Distribution Systems Operator (DSO) and IPP in order to maintain voltage levels within mandatory limits. The comparison is conducted by means of a time series simulation analysis on a real MV Italian distribution system.
{"title":"Comparison of voltage control methods for incrementing active power production","authors":"V. Calderaro, V. Galdi, G. Graditi, F. Lamberti","doi":"10.1109/ENERGYCON.2014.6850560","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850560","url":null,"abstract":"Due to the increasing development of Distributed Generation (DG) based on renewable energy sources (RESs), currently voltage control represents an important issue in distribution power systems. In this paper, we propose a comparison between two voltage control methods that allow obtaining the maximum available power production from wind turbines and photovoltaic systems. Both methods suppose a wind and photovoltaic plants belonging to an Independent Power Producer (IPP) able to control each RES units. The first method is based on a coordinated local control approach that takes advantage of a mixed Distribution Network (DN) sensitivity analysis; the second one is based on a cooperation of data transfer between Distribution Systems Operator (DSO) and IPP in order to maintain voltage levels within mandatory limits. The comparison is conducted by means of a time series simulation analysis on a real MV Italian distribution system.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114224845","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850547
E. Ikonen, István Selek, J. Kovács, Markus Neuvonen, Z. Szabo, J. Bene, Jani Peurasaari
The increasing challenges in district heating operational optimization are briefly discussed. The paper describes the first steps in a research project on minimization of short term operational costs in a full scale district heating system. Based on a test model describing a part of a real district heating network, and a chosen approximate dynamic programming technique, simulations are used to illustrate and validate the fundamentals of the modelling and optimization approaches. It is concluded that the considered methods provide an adequate set of tools for the design of optimal network loading. The project is currently continuing with building of a more realistic dynamic model of the full-scale energy network and its components.
{"title":"Short term optimization of district heating network supply temperatures","authors":"E. Ikonen, István Selek, J. Kovács, Markus Neuvonen, Z. Szabo, J. Bene, Jani Peurasaari","doi":"10.1109/ENERGYCON.2014.6850547","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850547","url":null,"abstract":"The increasing challenges in district heating operational optimization are briefly discussed. The paper describes the first steps in a research project on minimization of short term operational costs in a full scale district heating system. Based on a test model describing a part of a real district heating network, and a chosen approximate dynamic programming technique, simulations are used to illustrate and validate the fundamentals of the modelling and optimization approaches. It is concluded that the considered methods provide an adequate set of tools for the design of optimal network loading. The project is currently continuing with building of a more realistic dynamic model of the full-scale energy network and its components.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127325201","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850518
S. D'Alessandro, A. Tonello, Andrea Monacchi, W. Elmenreich
Households account for a notable amount of overall energy consumption, thus they represent a field where it is possible to potentially obtain great energy savings. Energy management systems (EMSs) can be used to this end. They allow for monitoring and managing energy consumption of household appliances or renewable energy sources, as well as making users aware of their energy consumptions. User awareness has been shown to yield up to 20% of energy savings. In this paper, we propose a design procedure for the communication network of a home energy management system (HEMS). We discuss design choices of a HEMS which is currently under development within the MONERGY project, an initiative aiming at boosting the energy awareness of households in two regions: Carinthia (Austria) and Friuli-Venezia Giulia (Italy). Although the system is tailored to the peculiarities of the regions, we believe that the proposed design guidelines can be of help for engineers of EMSs. In particular, the work addresses key issues of the communication network requirements such as coverage, topology, number of nodes, metering resolution and communication technologies. Furthermore, real world tests of wireless and power line communication (PLC) technologies are carried out to see whether existing HEMSs satisfy the communication network requirements.
{"title":"Home energy management systems: Design guidelines for the communication infrastructure","authors":"S. D'Alessandro, A. Tonello, Andrea Monacchi, W. Elmenreich","doi":"10.1109/ENERGYCON.2014.6850518","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850518","url":null,"abstract":"Households account for a notable amount of overall energy consumption, thus they represent a field where it is possible to potentially obtain great energy savings. Energy management systems (EMSs) can be used to this end. They allow for monitoring and managing energy consumption of household appliances or renewable energy sources, as well as making users aware of their energy consumptions. User awareness has been shown to yield up to 20% of energy savings. In this paper, we propose a design procedure for the communication network of a home energy management system (HEMS). We discuss design choices of a HEMS which is currently under development within the MONERGY project, an initiative aiming at boosting the energy awareness of households in two regions: Carinthia (Austria) and Friuli-Venezia Giulia (Italy). Although the system is tailored to the peculiarities of the regions, we believe that the proposed design guidelines can be of help for engineers of EMSs. In particular, the work addresses key issues of the communication network requirements such as coverage, topology, number of nodes, metering resolution and communication technologies. Furthermore, real world tests of wireless and power line communication (PLC) technologies are carried out to see whether existing HEMSs satisfy the communication network requirements.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126326926","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850591
V. Mariani, F. Vasca, Josep M. Guerrero
Three-phase droop controlled inverters are widely used in islanded microgrids to interface distributed energy resources and to provide for the loads active and reactive powers demand. The assessment of microgrids stability, affected by the control and line parameters, is a stringent issue. This paper shows a systematic approach to derive a closed loop model of the microgrid and then to perform an eigenvalues analysis that highlights how the system's parameters affect the stability of the network. It is also shown that by means of a singular perturbation approach the resulting reduced order system well approximate the original full order system.
{"title":"Analysis of droop controlled parallel inverters in islanded microgrids","authors":"V. Mariani, F. Vasca, Josep M. Guerrero","doi":"10.1109/ENERGYCON.2014.6850591","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850591","url":null,"abstract":"Three-phase droop controlled inverters are widely used in islanded microgrids to interface distributed energy resources and to provide for the loads active and reactive powers demand. The assessment of microgrids stability, affected by the control and line parameters, is a stringent issue. This paper shows a systematic approach to derive a closed loop model of the microgrid and then to perform an eigenvalues analysis that highlights how the system's parameters affect the stability of the network. It is also shown that by means of a singular perturbation approach the resulting reduced order system well approximate the original full order system.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124340426","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850569
R. Lamedica, E. Santini, D. Z. Romito
This paper describes a technique for the selection of an heating system, among a choice of technologies, depending only on the environmental sustainability of the system itself. The analytical bases of this technique are introduced and a suitable numerical procedure is developed. The software implementation, built by the Authors in a Matlab environment, is described and numerical results are shown.
{"title":"A new algorithm for numerical comparison of environmental sustainability of heating systems","authors":"R. Lamedica, E. Santini, D. Z. Romito","doi":"10.1109/ENERGYCON.2014.6850569","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850569","url":null,"abstract":"This paper describes a technique for the selection of an heating system, among a choice of technologies, depending only on the environmental sustainability of the system itself. The analytical bases of this technique are introduced and a suitable numerical procedure is developed. The software implementation, built by the Authors in a Matlab environment, is described and numerical results are shown.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121916490","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850423
P. Nicolae, I. Nicolae, D. Popa
This paper presents measurements of power quality indices for a static excitation system composed of transformer and controlled rectifier bridge in a power system generator group and the corresponding MATLAB/Simulink simulation. Replacing the old auxiliary excitation generator eliminates the disadvantage of using electrical machines with the mass in motion inertia and wear over time, but with the price of facing two important problems: the line voltage notching due to thyristor commutation and also the distorting of line current. Theoretical aspects of line notching and several solutions for compensation strategies and their limitations are discussed. The MATLAB/Simulink model allows us to implement the solution we chosen to deal with these problems and observe its effectiveness based on the results.
{"title":"Analysis and simulation of distorting regime compensation for a static excitation system in a power system through passive filtering","authors":"P. Nicolae, I. Nicolae, D. Popa","doi":"10.1109/ENERGYCON.2014.6850423","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850423","url":null,"abstract":"This paper presents measurements of power quality indices for a static excitation system composed of transformer and controlled rectifier bridge in a power system generator group and the corresponding MATLAB/Simulink simulation. Replacing the old auxiliary excitation generator eliminates the disadvantage of using electrical machines with the mass in motion inertia and wear over time, but with the price of facing two important problems: the line voltage notching due to thyristor commutation and also the distorting of line current. Theoretical aspects of line notching and several solutions for compensation strategies and their limitations are discussed. The MATLAB/Simulink model allows us to implement the solution we chosen to deal with these problems and observe its effectiveness based on the results.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122438809","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 : 2014-05-13DOI: 10.1109/ENERGYCON.2014.6850577
L. Exel, Georg Frey
A general forecasting concept for power systems is developed based on a detailed requirement analysis concerning a forecasting system for supply-dependent feed-in units within the present and future electrical grid. The fundamental idea is an agent-based system in which each single supply entity determines and communicates its own feed-in forecast. The contribution describes the proposed architecture and defines a corresponding data structure which includes information about the uncertainty of the individual forecast. To demonstrate the feasibility, the design of the forecast agent at entity level is presented in more detail and discussed in relation to a solar energy system.
{"title":"Toward a decentralized forecast system for distributed power generation","authors":"L. Exel, Georg Frey","doi":"10.1109/ENERGYCON.2014.6850577","DOIUrl":"https://doi.org/10.1109/ENERGYCON.2014.6850577","url":null,"abstract":"A general forecasting concept for power systems is developed based on a detailed requirement analysis concerning a forecasting system for supply-dependent feed-in units within the present and future electrical grid. The fundamental idea is an agent-based system in which each single supply entity determines and communicates its own feed-in forecast. The contribution describes the proposed architecture and defines a corresponding data structure which includes information about the uncertainty of the individual forecast. To demonstrate the feasibility, the design of the forecast agent at entity level is presented in more detail and discussed in relation to a solar energy system.","PeriodicalId":410611,"journal":{"name":"2014 IEEE International Energy Conference (ENERGYCON)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122125471","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：