Pub Date : 2015-10-01DOI: 10.1109/INTLEC.2015.7572450
Xiaofei Zhang, Wang Zhen, Shu Zhou
Modular UPSs have more than ten years of history, and have been widely used in large data centers thanks to their features of high availability, high scalability, easy maintenance, high efficiency, and many other advantages. The reliability of a modular UPS primarily depends on the system architecture design which should be simple and decoupled to avoid single points of failure. Key parts such as power modules, control modules, the system communication bus, power supply, and fans must be redundant. The UPS system reliability also depends on the system fault detection and isolation mechanisms, which ensure that a faulty unit is promptly detected and automatically isolated from the system so that remaining operational units can continue supplying power safely. Lastly, real-time detection and health condition evaluation of vulnerable devices ensure long term reliable operation of the power supply system. Leveraging its powerful and professional test verification platform, Huawei verifies and optimizes its modular UPS products through 21 special reliability tests, ensuring strong UPS adaptability to power grids, various environments, and loads.
{"title":"How to ensure the modular UPS with high reliability","authors":"Xiaofei Zhang, Wang Zhen, Shu Zhou","doi":"10.1109/INTLEC.2015.7572450","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572450","url":null,"abstract":"Modular UPSs have more than ten years of history, and have been widely used in large data centers thanks to their features of high availability, high scalability, easy maintenance, high efficiency, and many other advantages. The reliability of a modular UPS primarily depends on the system architecture design which should be simple and decoupled to avoid single points of failure. Key parts such as power modules, control modules, the system communication bus, power supply, and fans must be redundant. The UPS system reliability also depends on the system fault detection and isolation mechanisms, which ensure that a faulty unit is promptly detected and automatically isolated from the system so that remaining operational units can continue supplying power safely. Lastly, real-time detection and health condition evaluation of vulnerable devices ensure long term reliable operation of the power supply system. Leveraging its powerful and professional test verification platform, Huawei verifies and optimizes its modular UPS products through 21 special reliability tests, ensuring strong UPS adaptability to power grids, various environments, and loads.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117006295","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572342
T. Kohama, Keisuke Takeshita, S. Tsuji
This paper proposes a simple circuit model to estimate output voltage fluctuation in paralleled converter system with optimized on-off control. The optimized on-off control method changes the number of active converter modules to minimize power losses in paralleled system according to load current. However, it causes voltage fluctuation in transient response. Output voltage fluctuation due to the on-off control is estimated with proposed simple circuit model. The estimation is verified by accurate circuit simulation. Simple guideline for circuit components is also given to meet a specific output voltage tolerance.
{"title":"Simple estimating method for voltage fluctuation in paralleled converter system with optimized on-off control","authors":"T. Kohama, Keisuke Takeshita, S. Tsuji","doi":"10.1109/INTLEC.2015.7572342","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572342","url":null,"abstract":"This paper proposes a simple circuit model to estimate output voltage fluctuation in paralleled converter system with optimized on-off control. The optimized on-off control method changes the number of active converter modules to minimize power losses in paralleled system according to load current. However, it causes voltage fluctuation in transient response. Output voltage fluctuation due to the on-off control is estimated with proposed simple circuit model. The estimation is verified by accurate circuit simulation. Simple guideline for circuit components is also given to meet a specific output voltage tolerance.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115567274","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572427
M. Steinberger, Johannes Geiling, R. Ochsner
Grid connected hybrid hydrogen systems consisting of an electrolyzer, a fuel cell and a battery may become major parts of local energy systems in future. System setup is quite challenging due to different electric constraints and the need for a gas management system. This paper presents planning for a technical setup using a DC micro grid and a hydrogen pressure tank and the development of a new control strategy. In order to ensure grid stability a multi-level control strategy with decentralized and centralized control loops is used. A state-based energy control algorithm was developed to provide services to the electric grid and to optimize the system. Simulation results covering a real office and research building proved the energy control system to be feasible and revealed which control parameters are critical such as hydrogen tank pressure. It can be shown that by using a hybrid hydrogen system the maximum peak load of the building can be reduced by 33 % This reduction can be maintained for more than 8650 hours a year and feeding excess energy into the mains can be avoided completely.
{"title":"Setup and state based energy control of a grid-connected multipurpose hybrid hydrogen system","authors":"M. Steinberger, Johannes Geiling, R. Ochsner","doi":"10.1109/INTLEC.2015.7572427","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572427","url":null,"abstract":"Grid connected hybrid hydrogen systems consisting of an electrolyzer, a fuel cell and a battery may become major parts of local energy systems in future. System setup is quite challenging due to different electric constraints and the need for a gas management system. This paper presents planning for a technical setup using a DC micro grid and a hydrogen pressure tank and the development of a new control strategy. In order to ensure grid stability a multi-level control strategy with decentralized and centralized control loops is used. A state-based energy control algorithm was developed to provide services to the electric grid and to optimize the system. Simulation results covering a real office and research building proved the energy control system to be feasible and revealed which control parameters are critical such as hydrogen tank pressure. It can be shown that by using a hybrid hydrogen system the maximum peak load of the building can be reduced by 33 % This reduction can be maintained for more than 8650 hours a year and feeding excess energy into the mains can be avoided completely.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115675637","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572426
M. Shimoda, T. Yachi, Y. Kanai
In this paper, we propose a new power peak shifting system that uses demand forecasting. The study is based on the assumption that a dynamic pricing system has been introduced to an office equipped with a data center. In addition, we report on the results of simulations that show our proposed peak shifting scheme improves system utility and strength through increased economic efficiency, even when the initial costs of supplementary power equipment such as photovoltaic systems and storage batteries are factored in.
{"title":"Economic evaluation of peak shift system using power demand forecasting","authors":"M. Shimoda, T. Yachi, Y. Kanai","doi":"10.1109/INTLEC.2015.7572426","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572426","url":null,"abstract":"In this paper, we propose a new power peak shifting system that uses demand forecasting. The study is based on the assumption that a dynamic pricing system has been introduced to an office equipped with a data center. In addition, we report on the results of simulations that show our proposed peak shifting scheme improves system utility and strength through increased economic efficiency, even when the initial costs of supplementary power equipment such as photovoltaic systems and storage batteries are factored in.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126913399","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572285
Chen Hong Wong
This paper looks at multiple energy sources now available at the cell site, as well as design and management complexities that have risen as a result. The goal of this paper is to outline design considerations for each alternative energy source, such as technologies, logistics, setup and operation. By showing these considerations, decision-makers can refine objectives for deployment and operation, and common integrated network solutions can be established, deployed and effectively managed to address rising energy consumption among telecom facilities.
{"title":"Hybrid energy deployment: What to consider when enabling alternative energy sources at the cell site","authors":"Chen Hong Wong","doi":"10.1109/INTLEC.2015.7572285","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572285","url":null,"abstract":"This paper looks at multiple energy sources now available at the cell site, as well as design and management complexities that have risen as a result. The goal of this paper is to outline design considerations for each alternative energy source, such as technologies, logistics, setup and operation. By showing these considerations, decision-makers can refine objectives for deployment and operation, and common integrated network solutions can be established, deployed and effectively managed to address rising energy consumption among telecom facilities.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125958924","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572381
F. Nagano, Youichi Ito
This paper propose a high efficiency DC-DC converter and simple control method for the multi energy source management. The proposed DC-DC converter consists of the two high efficiency DC-DC converters such as the switched capacitor DC-DC converter and Current resonant type isolated DC-DC converter. In addition, this paper describes the novel control method for the multi energy source management. The proposed method achieves a simple control method based on the constant DC voltage control and droop characteristics.
{"title":"A novel control strategy for multi energy source power supply for DC link connection","authors":"F. Nagano, Youichi Ito","doi":"10.1109/INTLEC.2015.7572381","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572381","url":null,"abstract":"This paper propose a high efficiency DC-DC converter and simple control method for the multi energy source management. The proposed DC-DC converter consists of the two high efficiency DC-DC converters such as the switched capacitor DC-DC converter and Current resonant type isolated DC-DC converter. In addition, this paper describes the novel control method for the multi energy source management. The proposed method achieves a simple control method based on the constant DC voltage control and droop characteristics.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127575654","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572495
Hiroyuki Hanaoka, H. Matsuo, Narumi Yanagisawa
In recent years, in overseas, particularly Asian countries, demand of UPS is growing up, the expansion of three-phase four-wire type UPS of the line-up for the Asian countries has come to be expected in our company. In this paper, based on the new way of thinking, we report that we have developed a three-phase four-wire type UPS in a short development period by applying the single-phase UPS that we have conventional. In addition, parallel operation method of A11J single-phase model is shown.
{"title":"The new concept for 3-phase 4-wire UPS system","authors":"Hiroyuki Hanaoka, H. Matsuo, Narumi Yanagisawa","doi":"10.1109/INTLEC.2015.7572495","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572495","url":null,"abstract":"In recent years, in overseas, particularly Asian countries, demand of UPS is growing up, the expansion of three-phase four-wire type UPS of the line-up for the Asian countries has come to be expected in our company. In this paper, based on the new way of thinking, we report that we have developed a three-phase four-wire type UPS in a short development period by applying the single-phase UPS that we have conventional. In addition, parallel operation method of A11J single-phase model is shown.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126356969","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572454
Yun Wang, Lu Xu, Jiankai Gao, Liwei Liu
Site infrastructure sharing is the trend of future base station construction. Telecom infrastructure operators require for smooth upgrading and low TCO when sharing sites power supply, spaces and operation management. This paper introduces a new integrated hybrid power supply system suitable for the site sharing requirements. It perfectly combines many functions together, such as energy generation, conversion, control, distribution and metering, which support multiple energy access including solar, grid, many kinds of battery storage, -48V DC power output directly with multi-channel distribution for different operators loads and common platform management and control for smooth upgrading of site sharing. With the integrated variable speed generator inside, the system can maximize the fuel efficiency based on the actual load capacity; accordingly, fuel consumption could be reduced sharply at low load capacity. Two systems can work in parallel with a total power output, making the expansion of energy generation easily, which could be applied to meet the increasing electricity requirements when more operators add in. This solution is much better than that has been applied before. The system is designed in the way that both power conversion modules and intelligent power distribution units can be smoothly expanded. AC/DC and DC/DC conversion modules can be exchanged freely in the same slot position to shrink the volume of the system. Besides, different battery storage group also can be expanded by HBTS (hybrid battery transfer system, embedded structure). The electricity used by different operators could be metered by central supervising unit or intelligent electric meter. The system combines multiple hybrid energy solutions to cope with different site sharing scenarios to comprehensively reduce site sharing TCO. It helps telecom infrastructure operators invest capital step by step and maximize the ROI.
{"title":"A new integrated hybrid power supply system for telecom site sharing solution","authors":"Yun Wang, Lu Xu, Jiankai Gao, Liwei Liu","doi":"10.1109/INTLEC.2015.7572454","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572454","url":null,"abstract":"Site infrastructure sharing is the trend of future base station construction. Telecom infrastructure operators require for smooth upgrading and low TCO when sharing sites power supply, spaces and operation management. This paper introduces a new integrated hybrid power supply system suitable for the site sharing requirements. It perfectly combines many functions together, such as energy generation, conversion, control, distribution and metering, which support multiple energy access including solar, grid, many kinds of battery storage, -48V DC power output directly with multi-channel distribution for different operators loads and common platform management and control for smooth upgrading of site sharing. With the integrated variable speed generator inside, the system can maximize the fuel efficiency based on the actual load capacity; accordingly, fuel consumption could be reduced sharply at low load capacity. Two systems can work in parallel with a total power output, making the expansion of energy generation easily, which could be applied to meet the increasing electricity requirements when more operators add in. This solution is much better than that has been applied before. The system is designed in the way that both power conversion modules and intelligent power distribution units can be smoothly expanded. AC/DC and DC/DC conversion modules can be exchanged freely in the same slot position to shrink the volume of the system. Besides, different battery storage group also can be expanded by HBTS (hybrid battery transfer system, embedded structure). The electricity used by different operators could be metered by central supervising unit or intelligent electric meter. The system combines multiple hybrid energy solutions to cope with different site sharing scenarios to comprehensively reduce site sharing TCO. It helps telecom infrastructure operators invest capital step by step and maximize the ROI.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121841538","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572361
Naoki Hanaoka, A. Takahashi, Toru Tanaka, N. Yamashita, M. Sugahara
To promote the widespread use of HVDC power supply systems, this paper proposes high-efficiency downsized power conversion (380 V to -48 V) equipment for HVDC use having a size small enough for mounting in the dead space of a rack and describes its performance. Configuring 380 V/-48 V conversion equipment with existing technology lowers the efficiency of the entire power supply system and increases the installation area. To solve these problems, it has become necessary to develop equipment with an efficiency of 97 % or greater and with dimensions (W43 × H400 × D80 mm) small enough for mounting in the dead space of a rack. To this end, we have achieved high efficiency and small size by adopting a circuit configuration that uses a compact, high-efficiency chip converter as used on motherboards in ICT equipment and that disconnects the voltage step-up circuit during normal operation. However, a chip converter incorporated in a power supply system may not necessarily operate in a stable manner. To achieve stable use, we performed a stability evaluation while establishing and verifying input/output conditions and taking chip-converter control characteristics into account. We used the results of this evaluation to equip the equipment with the necessary measures to ensure stability.
{"title":"Development of high-efficiency downsized power conversion (380 V to −48 V) equipment for HVDC power supply system","authors":"Naoki Hanaoka, A. Takahashi, Toru Tanaka, N. Yamashita, M. Sugahara","doi":"10.1109/INTLEC.2015.7572361","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572361","url":null,"abstract":"To promote the widespread use of HVDC power supply systems, this paper proposes high-efficiency downsized power conversion (380 V to -48 V) equipment for HVDC use having a size small enough for mounting in the dead space of a rack and describes its performance. Configuring 380 V/-48 V conversion equipment with existing technology lowers the efficiency of the entire power supply system and increases the installation area. To solve these problems, it has become necessary to develop equipment with an efficiency of 97 % or greater and with dimensions (W43 × H400 × D80 mm) small enough for mounting in the dead space of a rack. To this end, we have achieved high efficiency and small size by adopting a circuit configuration that uses a compact, high-efficiency chip converter as used on motherboards in ICT equipment and that disconnects the voltage step-up circuit during normal operation. However, a chip converter incorporated in a power supply system may not necessarily operate in a stable manner. To achieve stable use, we performed a stability evaluation while establishing and verifying input/output conditions and taking chip-converter control characteristics into account. We used the results of this evaluation to equip the equipment with the necessary measures to ensure stability.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126443914","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 : 2015-10-01DOI: 10.1109/INTLEC.2015.7572310
H. Kidokoro, M. Nakahara
To take advantage of volatile renewable energy, implementation of digital control is effective since it supports the application of various advanced control theory and communication functions. However, it is usually difficult to use the actual plant to be controlled at the control software development stage, particularly in terms of cost and safety. Therefore, during the control software development phase, it is expected to substitute a Hardware-in-the-Loop (HIL-simulator) so that the controller hardware can be placed in the feedback control loop for the actual plant. The development of HIL-simulators for the switching converter has been recognized to be a challenge because of the high control frequencies involved. However, it is possible to realize a HIL-simulator using a partial variable step method that is able to compute switching behavior in a precise manner and with state space equations that help minimize the calculation time required for the execution of the aforementioned method. This technique can also be applied to slower computational devices such as microprocessors. However, using FPGA, it is possible to develop a more realistic simulator with minimal computational delay. This study describes a HIL-simulator that simulates the electrical circuit of the switching converter that is able to provide 0.1% duty ratio resolution at a 100 kHz switching frequency.
{"title":"FPGA-based hardware-in-the-loop simulator of high switching frequency power converters","authors":"H. Kidokoro, M. Nakahara","doi":"10.1109/INTLEC.2015.7572310","DOIUrl":"https://doi.org/10.1109/INTLEC.2015.7572310","url":null,"abstract":"To take advantage of volatile renewable energy, implementation of digital control is effective since it supports the application of various advanced control theory and communication functions. However, it is usually difficult to use the actual plant to be controlled at the control software development stage, particularly in terms of cost and safety. Therefore, during the control software development phase, it is expected to substitute a Hardware-in-the-Loop (HIL-simulator) so that the controller hardware can be placed in the feedback control loop for the actual plant. The development of HIL-simulators for the switching converter has been recognized to be a challenge because of the high control frequencies involved. However, it is possible to realize a HIL-simulator using a partial variable step method that is able to compute switching behavior in a precise manner and with state space equations that help minimize the calculation time required for the execution of the aforementioned method. This technique can also be applied to slower computational devices such as microprocessors. However, using FPGA, it is possible to develop a more realistic simulator with minimal computational delay. This study describes a HIL-simulator that simulates the electrical circuit of the switching converter that is able to provide 0.1% duty ratio resolution at a 100 kHz switching frequency.","PeriodicalId":211948,"journal":{"name":"2015 IEEE International Telecommunications Energy Conference (INTELEC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130480699","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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