Pub Date : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982345
Ruslans Muhitovs, M. Mezitis, J. Freimane
The article gives overview on different methods of point heating systems. Their advantages and disadvantages are described. For point electric heating, an amount of consumed electric energy by station type is given. Existing methods of point heating control are reviewed and compared; their disadvantages are listed. As a proposed solution to the described problem, an intelligent point electric heating control system is proposed and described. Experiment of controlling point heating system by using pulse-width modulation method is set and its results are compared with theoretically calculated ones. Conclusions show that the approach of introducing pulse-width modulation allows to control point heating in more efficient way - using program code, control system will decide automatically when to switch the heating on and off.
{"title":"Intelligent Railway Point Electric Heating Control System","authors":"Ruslans Muhitovs, M. Mezitis, J. Freimane","doi":"10.1109/RTUCON48111.2019.8982345","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982345","url":null,"abstract":"The article gives overview on different methods of point heating systems. Their advantages and disadvantages are described. For point electric heating, an amount of consumed electric energy by station type is given. Existing methods of point heating control are reviewed and compared; their disadvantages are listed. As a proposed solution to the described problem, an intelligent point electric heating control system is proposed and described. Experiment of controlling point heating system by using pulse-width modulation method is set and its results are compared with theoretically calculated ones. Conclusions show that the approach of introducing pulse-width modulation allows to control point heating in more efficient way - using program code, control system will decide automatically when to switch the heating on and off.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115296397","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982309
J. Survilo
In power lines with prevailing wire resistance, voltage loss can be varied changing the cross-section area of the conductors on the path from the beginning to the consumer in question. The enlargement of cross-section area of wires of all line segments of the path should be such that the summary increase of wire cost is minimum. This occurs when derivatives of the wire costs by voltage loss of this wire for all segments of the path are equal. The said derivative can be determined using curves of conductor cost as function of current density. The lowest per unit of transferred energy cost of an optimum fed zone, with transformer located properly in the zone, takes place when, enlarging the zone, the decrement of transformer per unit cost equals to the increment of grid per unit cost. If for cost effective wires in optimum fed zone the condition of voltage loss is not met, the options should be considered increasing the cross-section of wires or decreasing the fed zone. If all necessary data are not possible, the said curve of cost versus current density can be built on the base of commerce data.
{"title":"Distribution Networks Including the Power Lines with Prevailing Resistance","authors":"J. Survilo","doi":"10.1109/RTUCON48111.2019.8982309","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982309","url":null,"abstract":"In power lines with prevailing wire resistance, voltage loss can be varied changing the cross-section area of the conductors on the path from the beginning to the consumer in question. The enlargement of cross-section area of wires of all line segments of the path should be such that the summary increase of wire cost is minimum. This occurs when derivatives of the wire costs by voltage loss of this wire for all segments of the path are equal. The said derivative can be determined using curves of conductor cost as function of current density. The lowest per unit of transferred energy cost of an optimum fed zone, with transformer located properly in the zone, takes place when, enlarging the zone, the decrement of transformer per unit cost equals to the increment of grid per unit cost. If for cost effective wires in optimum fed zone the condition of voltage loss is not met, the options should be considered increasing the cross-section of wires or decreasing the fed zone. If all necessary data are not possible, the said curve of cost versus current density can be built on the base of commerce data.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123708943","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982346
Alexey Romanov
Intelligent information processing technologies are already widely used in the power industry. The new step in their evolution was made with application of Internet-of-Things(IoT) devices into a smart grid. A key problem of intelligent IoT device development is implementation of a data processing algorithms on a low-power on-board processing units. The paper proposes a high efficient technology for neural network implementation on a FPGA-based IoT devices. An approach based on the use of sigma-delta modulated bitstreams for signal representation is proposed, which makes it possible to reduce the size of all elements of neural network and to provide the possibility of completely parallel implementation of neural networks and adaptive network-based fuzzy inference systems (ANFIS) on the basis of existing FPGA microchips. Based on the proposed approach, the novel FPGA IP cores are developed for the implementation of direct propagation neural networks, RBF-networks and ANFIS. The FPGA resource usage efficiency of the developed solutions is demonstrated using synthesis results on modern FPGA. The proposed approach will increase performance of IoT devices, designed for smart-grid.
{"title":"High-efficient implementation of neural networks and ANFIS using direct bitstream processing","authors":"Alexey Romanov","doi":"10.1109/RTUCON48111.2019.8982346","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982346","url":null,"abstract":"Intelligent information processing technologies are already widely used in the power industry. The new step in their evolution was made with application of Internet-of-Things(IoT) devices into a smart grid. A key problem of intelligent IoT device development is implementation of a data processing algorithms on a low-power on-board processing units. The paper proposes a high efficient technology for neural network implementation on a FPGA-based IoT devices. An approach based on the use of sigma-delta modulated bitstreams for signal representation is proposed, which makes it possible to reduce the size of all elements of neural network and to provide the possibility of completely parallel implementation of neural networks and adaptive network-based fuzzy inference systems (ANFIS) on the basis of existing FPGA microchips. Based on the proposed approach, the novel FPGA IP cores are developed for the implementation of direct propagation neural networks, RBF-networks and ANFIS. The FPGA resource usage efficiency of the developed solutions is demonstrated using synthesis results on modern FPGA. The proposed approach will increase performance of IoT devices, designed for smart-grid.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129468073","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982298
A. Berdin, P. Kovalenko
The possibility assumed in previous research of utilizing the linear model for defining the power system frequency static response slope based on synchrophasor data of transients accompanied by frequency changes is investigated in detail. Square model usage is considered. The comparison is done using 13 recordings of events that caused frequency deviations in Northern part of Tyumen region including four considered in the previous publication.
{"title":"Comparing the Linear and Square Models for Defining the Power System Frequency Static Response Slope based on Transient Synchrophasor Data","authors":"A. Berdin, P. Kovalenko","doi":"10.1109/RTUCON48111.2019.8982298","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982298","url":null,"abstract":"The possibility assumed in previous research of utilizing the linear model for defining the power system frequency static response slope based on synchrophasor data of transients accompanied by frequency changes is investigated in detail. Square model usage is considered. The comparison is done using 13 recordings of events that caused frequency deviations in Northern part of Tyumen region including four considered in the previous publication.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129108394","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982267
H. S. Aliyev, S. Namazov, M. M. Guliyev, R. S. Ismayilova
The thermal conductivity of polyvinylchloride (PVC) containing graphite (Gr) micro fillers have been studied because of their potential applications in power electronics devices, batteries, electromagnetic shielding, antistatic and corrosion resistant coatings and other functional applications. Micro - composites containing (2, 4, 6, 8, 10, and 12%) volume fractions of graphite were fabricated. The thermal conductivity (K) of composites is enhanced by ~420% as concentration is increased from 0 to 12vol. %. Composites with a higher concentration show a stronger dependence in the thermal conductivity. It was revealed that, upon heating and cooling of these heterogeneous macro systems, hysteresis phenomena based on the effect of the “asymmetry” of the temperature evolution of the electrically active defects appear at the temperatures T<80°C. During the heating -cooling cycle, the relative changes in the ε′ and tanδ with the temperature were about 33 and 61%, respectively.
{"title":"Thermally conducting composites for power electronics","authors":"H. S. Aliyev, S. Namazov, M. M. Guliyev, R. S. Ismayilova","doi":"10.1109/RTUCON48111.2019.8982267","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982267","url":null,"abstract":"The thermal conductivity of polyvinylchloride (PVC) containing graphite (Gr) micro fillers have been studied because of their potential applications in power electronics devices, batteries, electromagnetic shielding, antistatic and corrosion resistant coatings and other functional applications. Micro - composites containing (2, 4, 6, 8, 10, and 12%) volume fractions of graphite were fabricated. The thermal conductivity (K) of composites is enhanced by ~420% as concentration is increased from 0 to 12vol. %. Composites with a higher concentration show a stronger dependence in the thermal conductivity. It was revealed that, upon heating and cooling of these heterogeneous macro systems, hysteresis phenomena based on the effect of the “asymmetry” of the temperature evolution of the electrically active defects appear at the temperatures T<80°C. During the heating -cooling cycle, the relative changes in the ε′ and tanδ with the temperature were about 33 and 61%, respectively.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128324780","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982327
A. Egorov, E. Kochneva, A. Larionova, E. Lyukhanov, S.E. Shender
Automated meter reading (AMR) systems of commercial electricity metering operating in the wholesale electricity market undergo mandatory metrological calibration and certification. However, during the lifetime of such metering systems, failure of measuring complexes occurs more often than the need to conduct another metrological calibration. Control of metrological characteristics of measuring complexes operating as a part of metering systems allows detecting metrological characteristics violation at calibration intervals. The existing AMR systems for electric power supply provides information on electric power consumption at power system connections with a discreteness of 1 hour or half an hour. Power balances design for grid sections taking into account substitution schemes of power system equipment, topology and methods of state evaluation theory allows to determine systematic and random errors of power metering systems at hourly intervals and to control their metrological characteristics at hourly and half-hourly intervals before the next metrological calibration. The monitoring method of electric power measuring complexes metrological characteristics with a discreteness of one hour at calibration intervals is proposed. Experiments have been carried out, measuring complexes those the accuracy classes exceed the maximum permissible values have been determined.
{"title":"AMR Complexes Metrological Characteristics Control at Calibration Time Intervals","authors":"A. Egorov, E. Kochneva, A. Larionova, E. Lyukhanov, S.E. Shender","doi":"10.1109/RTUCON48111.2019.8982327","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982327","url":null,"abstract":"Automated meter reading (AMR) systems of commercial electricity metering operating in the wholesale electricity market undergo mandatory metrological calibration and certification. However, during the lifetime of such metering systems, failure of measuring complexes occurs more often than the need to conduct another metrological calibration. Control of metrological characteristics of measuring complexes operating as a part of metering systems allows detecting metrological characteristics violation at calibration intervals. The existing AMR systems for electric power supply provides information on electric power consumption at power system connections with a discreteness of 1 hour or half an hour. Power balances design for grid sections taking into account substitution schemes of power system equipment, topology and methods of state evaluation theory allows to determine systematic and random errors of power metering systems at hourly intervals and to control their metrological characteristics at hourly and half-hourly intervals before the next metrological calibration. The monitoring method of electric power measuring complexes metrological characteristics with a discreteness of one hour at calibration intervals is proposed. Experiments have been carried out, measuring complexes those the accuracy classes exceed the maximum permissible values have been determined.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127802230","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982365
Noman Shabbir, Roya Ahmadiahangar, L. Kütt, M. N. Iqbal, A. Rosin
Wind power is very different from other sources due to its volatile and stochastic nature. The forecasting of wind energy generation is a very important aspect for the reliability and challenges regarding balancing the supply and demand in power systems. In this paper, Support Vector Machine (SVM) based regression algorithm is used for one day ahead prediction of wind energy production in Estonia. The proposed algorithm is then compared with the results of the prediction algorithm used by the Estonian energy regulatory organization. The results indicate that our proposed algorithms give better forecasting and the lowest Root Mean Square Error (RMSE) values.
{"title":"Forecasting Short Term Wind Energy Generation using Machine Learning","authors":"Noman Shabbir, Roya Ahmadiahangar, L. Kütt, M. N. Iqbal, A. Rosin","doi":"10.1109/RTUCON48111.2019.8982365","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982365","url":null,"abstract":"Wind power is very different from other sources due to its volatile and stochastic nature. The forecasting of wind energy generation is a very important aspect for the reliability and challenges regarding balancing the supply and demand in power systems. In this paper, Support Vector Machine (SVM) based regression algorithm is used for one day ahead prediction of wind energy production in Estonia. The proposed algorithm is then compared with the results of the prediction algorithm used by the Estonian energy regulatory organization. The results indicate that our proposed algorithms give better forecasting and the lowest Root Mean Square Error (RMSE) values.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116224297","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982262
J. Survilo
Power line, where more than two distributed parameters (resistance and reactance) are taken into account, is considered as two-port network. Formulas, giving an unambiguous relationship between electrical quantities at the ports of a two-port network, do not detailed show the influence of three or four parameters (in addition, conductance and capacitive susceptance) on line electrical quantities. The influence of distributed parameters occurs through the sine and hyperbolic sine of the components of propagation factor. How distributed parameters should be changed it depends on what properties of the line it is desirable to get. More adverse of distributed parameters is specific susceptance both in single and parallel lines.
{"title":"Influence of Power Line Parameters on Their Properties","authors":"J. Survilo","doi":"10.1109/RTUCON48111.2019.8982262","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982262","url":null,"abstract":"Power line, where more than two distributed parameters (resistance and reactance) are taken into account, is considered as two-port network. Formulas, giving an unambiguous relationship between electrical quantities at the ports of a two-port network, do not detailed show the influence of three or four parameters (in addition, conductance and capacitive susceptance) on line electrical quantities. The influence of distributed parameters occurs through the sine and hyperbolic sine of the components of propagation factor. How distributed parameters should be changed it depends on what properties of the line it is desirable to get. More adverse of distributed parameters is specific susceptance both in single and parallel lines.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121771911","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982316
L. Petrichenko, R. Petrichenko, A. Sauhats
In this paper, our aim is to develop the model of weekly BESS scheduling and thus consider the type and parameters of the BESS, as well as present the algorithms of BESS charge/discharge cycle distribution. To achieve this goal, we analyse how the number of charge/discharge cycles performed during the planning period affects the revenue potential of energy storage. The objective function of the optimisation problem is formulated in the form of weekly avoided costs. A limited number of cycles per week is distributed day by day, using an optimisation procedure, since the optimal distribution is not uniform.
{"title":"The Choice of the Number of Charge/Discharge Cycles for a Battery Energy Storage System","authors":"L. Petrichenko, R. Petrichenko, A. Sauhats","doi":"10.1109/RTUCON48111.2019.8982316","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982316","url":null,"abstract":"In this paper, our aim is to develop the model of weekly BESS scheduling and thus consider the type and parameters of the BESS, as well as present the algorithms of BESS charge/discharge cycle distribution. To achieve this goal, we analyse how the number of charge/discharge cycles performed during the planning period affects the revenue potential of energy storage. The objective function of the optimisation problem is formulated in the form of weekly avoided costs. A limited number of cycles per week is distributed day by day, using an optimisation procedure, since the optimal distribution is not uniform.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126905183","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 : 2019-10-01DOI: 10.1109/RTUCON48111.2019.8982337
M. F. Abdel-Fattah, J. Punt
The energy market is becoming more flexible and as a result the change on energy price over the day will be significant. In smart-grids, energy storage systems play an important role and consequently it might be feasible to consider it for private households. Furthermore, the integration of solar photovoltaic systems might build an efficient energy systems. This paper presents investigations on a developed energy system for homes which includes solar photovoltaic systems and battery energy storage systems. The presented analysis and economic evaluation are based on the case study of an average Ontario household. The system evaluation used a simple basic analysis, considering a simple system, and investigated the economic aspect possibilities. The evaluation includes the energy savings from self-generated energy from the solar photovoltaic system and the stored energy on the battery energy storage system. Some conclusions regarding the current situation, the suggested solutions and further possibilities are presented.
{"title":"Investigations on the Integration of Solar Photovoltaic with Battery Energy Storage for Home Energy Systems","authors":"M. F. Abdel-Fattah, J. Punt","doi":"10.1109/RTUCON48111.2019.8982337","DOIUrl":"https://doi.org/10.1109/RTUCON48111.2019.8982337","url":null,"abstract":"The energy market is becoming more flexible and as a result the change on energy price over the day will be significant. In smart-grids, energy storage systems play an important role and consequently it might be feasible to consider it for private households. Furthermore, the integration of solar photovoltaic systems might build an efficient energy systems. This paper presents investigations on a developed energy system for homes which includes solar photovoltaic systems and battery energy storage systems. The presented analysis and economic evaluation are based on the case study of an average Ontario household. The system evaluation used a simple basic analysis, considering a simple system, and investigated the economic aspect possibilities. The evaluation includes the energy savings from self-generated energy from the solar photovoltaic system and the stored energy on the battery energy storage system. Some conclusions regarding the current situation, the suggested solutions and further possibilities are presented.","PeriodicalId":317349,"journal":{"name":"2019 IEEE 60th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)","volume":"284 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131491582","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：