Pub Date : 2013-10-01DOI: 10.1109/ICEMS.2013.6754544
Y. Sugawara, K. Akatsu
This paper shows characteristics of a Switched Reluctance Motor (SRM) using a Grain-Oriented electric steel. In general, most of SRMs use the Non-Oriented electrical steel sheet. The Grain-Oriented electric steel sheet has good magnetic characteristic in the rolling direction. However there is few application of rotating machines which use the steel. This paper shows an effectiveness of the SRM with the steel.
{"title":"Characteristics of a Switched Reluctance Motor using Grain-Oriented electric steel sheet","authors":"Y. Sugawara, K. Akatsu","doi":"10.1109/ICEMS.2013.6754544","DOIUrl":"https://doi.org/10.1109/ICEMS.2013.6754544","url":null,"abstract":"This paper shows characteristics of a Switched Reluctance Motor (SRM) using a Grain-Oriented electric steel. In general, most of SRMs use the Non-Oriented electrical steel sheet. The Grain-Oriented electric steel sheet has good magnetic characteristic in the rolling direction. However there is few application of rotating machines which use the steel. This paper shows an effectiveness of the SRM with the steel.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134319737","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579133
Thomas Coulot, E. Rouat, F. Hasbani, E. Lauga-Larroze, J. Fournier
A 90nm 1.4-3.3V CMOS Low-Dropout regulator for noise-sensitive low-current RF blocks in mixed SoC applications is presented. It is based on a two loops topology with replica technique and an additional Gm-C filter introduced in the replica loop for high power supply rejection at both low and high frequencies. Complete PSR and stability analyses are presented. The regulator is implemented in a 90nm CMOS technology and achieves a PSR better than -60dB from 0 to 30MHz with only a 47nF external output capacitor. This architecture is highly versatile since the replica design may remain very basic. The active chip area is only 0.0088mm2, making this LDO an ideal block for a locally distributed power management strategy.
{"title":"High power supply rejection wideband Low-Dropout regulator","authors":"Thomas Coulot, E. Rouat, F. Hasbani, E. Lauga-Larroze, J. Fournier","doi":"10.1109/ECCE-ASIA.2013.6579133","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579133","url":null,"abstract":"A 90nm 1.4-3.3V CMOS Low-Dropout regulator for noise-sensitive low-current RF blocks in mixed SoC applications is presented. It is based on a two loops topology with replica technique and an additional Gm-C filter introduced in the replica loop for high power supply rejection at both low and high frequencies. Complete PSR and stability analyses are presented. The regulator is implemented in a 90nm CMOS technology and achieves a PSR better than -60dB from 0 to 30MHz with only a 47nF external output capacitor. This architecture is highly versatile since the replica design may remain very basic. The active chip area is only 0.0088mm2, making this LDO an ideal block for a locally distributed power management strategy.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115411607","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579148
M. Rottach, C. Gerada, P. Wheeler
High availability and safety is a major concern for many actuation applications. Fault-tolerant electrical machines and power converters help achieving this goal but component overrating and system complexity have to be minimised for favourable system designs. This paper will assess several segmentation strategies of fault-tolerant permanent magnet machines on the example of an aerospace actuation system and examine the impacts on system weight and complexity. Considerable detail will be presented on the integration of multi 3-phase machine units in a common motor housing alongside with a detailed comparison between axial and circumferential segmentation, which to the knowledge of the authors has not been published before. A helicopter primary flight control actuation application is used to compare segmentation strategies. Initial results suggest that circumferential machine segmentation and a single layer concentrated winding arrangement are most suitable for applications with a high level of required fault tolerance and high peak to rated torque and speed ratio.
{"title":"Evaluation of motor-drive segmentation strategies for fault-tolerance","authors":"M. Rottach, C. Gerada, P. Wheeler","doi":"10.1109/ECCE-ASIA.2013.6579148","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579148","url":null,"abstract":"High availability and safety is a major concern for many actuation applications. Fault-tolerant electrical machines and power converters help achieving this goal but component overrating and system complexity have to be minimised for favourable system designs. This paper will assess several segmentation strategies of fault-tolerant permanent magnet machines on the example of an aerospace actuation system and examine the impacts on system weight and complexity. Considerable detail will be presented on the integration of multi 3-phase machine units in a common motor housing alongside with a detailed comparison between axial and circumferential segmentation, which to the knowledge of the authors has not been published before. A helicopter primary flight control actuation application is used to compare segmentation strategies. Initial results suggest that circumferential machine segmentation and a single layer concentrated winding arrangement are most suitable for applications with a high level of required fault tolerance and high peak to rated torque and speed ratio.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127315510","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579214
C. Chun, Gab-Su Seo, B. Cho, Jonghoon Kim
This paper proposes a fast state-of-charge (SOC) estimation algorithm for LiFePO4 batteries utilizing an extended Kalman filter (EKF). The proposed algorithm controls error covariance to expedite the SOC convergence against an initial error and alleviate undesired SOC fluctuation with a simplified hysteresis model. The new model not only well describes OCV hysteresis of the battery, but also requires less resources by linearization. To validate the performance of the proposed estimation method, a scaled-down hybrid electric vehicle (HEV) current profile is used for a 14Ah LiFePO4 battery cell. The experimental results verify the improved estimation speed as well as the feasibility of the proposed linearized model.
{"title":"A fast state-of-charge estimation algorithm for LiFePO4 batteries utilizing extended Kalman filter","authors":"C. Chun, Gab-Su Seo, B. Cho, Jonghoon Kim","doi":"10.1109/ECCE-ASIA.2013.6579214","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579214","url":null,"abstract":"This paper proposes a fast state-of-charge (SOC) estimation algorithm for LiFePO4 batteries utilizing an extended Kalman filter (EKF). The proposed algorithm controls error covariance to expedite the SOC convergence against an initial error and alleviate undesired SOC fluctuation with a simplified hysteresis model. The new model not only well describes OCV hysteresis of the battery, but also requires less resources by linearization. To validate the performance of the proposed estimation method, a scaled-down hybrid electric vehicle (HEV) current profile is used for a 14Ah LiFePO4 battery cell. The experimental results verify the improved estimation speed as well as the feasibility of the proposed linearized model.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125872045","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579158
Haihong Huang, Huan Xue, Xin Liu, Haixin Wang
As a study of APF (Active Power Filter) using a universal harmonic detection method, an experimental prototype of three-phase APF is built based on DSP (Digital signal processor) TMS320F2812. Based on the instantaneous reactive-power theory, the phase current is decomposed and analyzed by mathematical method and a new detecting method of harmonic and reactive currents for three-phase circuit is presented. The universal method can be used for both three-phase and single-phase APF by omitting the process of coordinate transformation which used in conventional p-q algorithm and ip-iq algorithm. Furthermore, this method can be used for either three-phase three-wire system or three-phase four-wire system. The results of simulation and experiment show that the experimental prototype can achieve harmonic current compensation effectively.
{"title":"The study of Active Power Filter using a universal harmonic detection method","authors":"Haihong Huang, Huan Xue, Xin Liu, Haixin Wang","doi":"10.1109/ECCE-ASIA.2013.6579158","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579158","url":null,"abstract":"As a study of APF (Active Power Filter) using a universal harmonic detection method, an experimental prototype of three-phase APF is built based on DSP (Digital signal processor) TMS320F2812. Based on the instantaneous reactive-power theory, the phase current is decomposed and analyzed by mathematical method and a new detecting method of harmonic and reactive currents for three-phase circuit is presented. The universal method can be used for both three-phase and single-phase APF by omitting the process of coordinate transformation which used in conventional p-q algorithm and ip-iq algorithm. Furthermore, this method can be used for either three-phase three-wire system or three-phase four-wire system. The results of simulation and experiment show that the experimental prototype can achieve harmonic current compensation effectively.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126116153","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579078
Vanxay Phimmasone, Yuta Kondo, Natsuki Shiota, M. Miyatake
Since PV power output depending on the operating voltage and current, PV systems need maximum power point tracker (MPPT). Further, multiple local maximum power points appear in the power-voltage characteristics under partial shading conditions, finding the global MPP using conventional MPPT is a difficult task. To solve this issue, the authors proposed a PSO technique to solve the problems involved in the MPPT. PSO-based MPPT can be used only one pair of sensors and able to control by a single centralized MPPT. These methods resulting in lower cost, higher overall efficiency and simplicity of its implementation. In this paper, the proposed methods, I-PSO, R-PSO and IR-PSO were used to verify their effectiveness on three photovoltaic arrays under different types of the change in insolation conditions through Simulations and demonstration experiments studies for the first time.
{"title":"The demonstration experiments to verify the effectiveness of the improved PSO-based MPPT controlling multiple photovoltaic arrays","authors":"Vanxay Phimmasone, Yuta Kondo, Natsuki Shiota, M. Miyatake","doi":"10.1109/ECCE-ASIA.2013.6579078","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579078","url":null,"abstract":"Since PV power output depending on the operating voltage and current, PV systems need maximum power point tracker (MPPT). Further, multiple local maximum power points appear in the power-voltage characteristics under partial shading conditions, finding the global MPP using conventional MPPT is a difficult task. To solve this issue, the authors proposed a PSO technique to solve the problems involved in the MPPT. PSO-based MPPT can be used only one pair of sensors and able to control by a single centralized MPPT. These methods resulting in lower cost, higher overall efficiency and simplicity of its implementation. In this paper, the proposed methods, I-PSO, R-PSO and IR-PSO were used to verify their effectiveness on three photovoltaic arrays under different types of the change in insolation conditions through Simulations and demonstration experiments studies for the first time.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"431 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123268899","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579147
J. Moon, Won-Sang Im, Jang-Mok Kim
This paper proposes a capacitance estimation method for the dc-link capacitor in brushless DC motor (BLDCM) drive systems. The proposed method is performed in the generating mode of the BLDCM. In this mode, the inverse dc current flows to the capacitor and the capacitor voltage is increased by the generating operation. Hence, the capacitance can be obtained from the variation of the capacitor voltage and average charging current to the capacitor. The proposed method provides a reliable and sensitive indication of capacitance without additional hardware requirements. The usefulness of the proposed capacitance estimation method is verified through the simulation and experimental results.
{"title":"Capacitance estimation of DC-link capacitor in brushless DC motor drive systems","authors":"J. Moon, Won-Sang Im, Jang-Mok Kim","doi":"10.1109/ECCE-ASIA.2013.6579147","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579147","url":null,"abstract":"This paper proposes a capacitance estimation method for the dc-link capacitor in brushless DC motor (BLDCM) drive systems. The proposed method is performed in the generating mode of the BLDCM. In this mode, the inverse dc current flows to the capacitor and the capacitor voltage is increased by the generating operation. Hence, the capacitance can be obtained from the variation of the capacitor voltage and average charging current to the capacitor. The proposed method provides a reliable and sensitive indication of capacitance without additional hardware requirements. The usefulness of the proposed capacitance estimation method is verified through the simulation and experimental results.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123710958","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579199
P. Mao, H. Jia, Chuanyim Wang, Ming Xu
Working principle of single-phase Boost-cascaded Boost-Buck(BoCBB) power factor correction converter is analyzed. On this basis, a new nonlinear current control method for buck converter is presented first, and a novel integrated control strategy constituting average current mode control and the above nonlinear current control method is proposed for BoCBB converter. With this control strategy, the BoCBB converter can work as a simple boost or a simple buck converter as required. That is, when the input voltage is lower than the output voltage, BoCBB works as a boost converter and the average current control method is used, and when the input voltage is higher than the output voltage, BoCBB works as a buck converter and the above nonlinear current control method is used. Compared with the traditional control scheme that the first-stage boost converter and second-stage buck converter are controlled independently, both the switching loss and voltage stress of the BoCBB can be reduced markedly, and the input current can be controlled more effectively not only in boost work mode, but also in buck work mode. Control diagram is given in this paper, and a 1.5kW rated single-phase boost-buck converter prototype controlled with digital signal processor (DSP) TMS28027 is built to verify the theoretical analysis. Experimental results shows that the output voltage can be regulated at a given value which is lower than peak line voltage, the input current can also be controlled into a sinusoidal waveform, and unit power factor is achieved meanwhile.
{"title":"Boost-Buck power factor correction converter with integrated different current control methods","authors":"P. Mao, H. Jia, Chuanyim Wang, Ming Xu","doi":"10.1109/ECCE-ASIA.2013.6579199","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579199","url":null,"abstract":"Working principle of single-phase Boost-cascaded Boost-Buck(BoCBB) power factor correction converter is analyzed. On this basis, a new nonlinear current control method for buck converter is presented first, and a novel integrated control strategy constituting average current mode control and the above nonlinear current control method is proposed for BoCBB converter. With this control strategy, the BoCBB converter can work as a simple boost or a simple buck converter as required. That is, when the input voltage is lower than the output voltage, BoCBB works as a boost converter and the average current control method is used, and when the input voltage is higher than the output voltage, BoCBB works as a buck converter and the above nonlinear current control method is used. Compared with the traditional control scheme that the first-stage boost converter and second-stage buck converter are controlled independently, both the switching loss and voltage stress of the BoCBB can be reduced markedly, and the input current can be controlled more effectively not only in boost work mode, but also in buck work mode. Control diagram is given in this paper, and a 1.5kW rated single-phase boost-buck converter prototype controlled with digital signal processor (DSP) TMS28027 is built to verify the theoretical analysis. Experimental results shows that the output voltage can be regulated at a given value which is lower than peak line voltage, the input current can also be controlled into a sinusoidal waveform, and unit power factor is achieved meanwhile.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125521580","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579277
Takehiro Takhashi, E. Ikawa, Inzunza Ruben, T. Ambo
The paper introduces development of the power inverter for the Power Conditioning System (PCS) for the middle scale Photo Voltaic (PV) power plants. The paper introduces two types of 100kW PCS with very high efficiency of 97.3% for indoor and outdoor installation. The feature of PCSs is the cooling. The 100kW PCSs are cooled only by natural convection. These are the world first PCSs eliminating the cooling fans, in this capacity range, realized by two key factors, loss reduction and sophisticated cooling design. This technology greatly reduces the maintenance works during the PV PCS life cycle and thus contributes efficient operation of PV plants. The cooling design and evaluation results are introduced in the paper. The 100kW PCSs are expected to contribute highly efficient operation of large scale PV plants for its life cycle.
{"title":"100kW high-power PV PCS with no cooling fans","authors":"Takehiro Takhashi, E. Ikawa, Inzunza Ruben, T. Ambo","doi":"10.1109/ECCE-ASIA.2013.6579277","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579277","url":null,"abstract":"The paper introduces development of the power inverter for the Power Conditioning System (PCS) for the middle scale Photo Voltaic (PV) power plants. The paper introduces two types of 100kW PCS with very high efficiency of 97.3% for indoor and outdoor installation. The feature of PCSs is the cooling. The 100kW PCSs are cooled only by natural convection. These are the world first PCSs eliminating the cooling fans, in this capacity range, realized by two key factors, loss reduction and sophisticated cooling design. This technology greatly reduces the maintenance works during the PV PCS life cycle and thus contributes efficient operation of PV plants. The cooling design and evaluation results are introduced in the paper. The 100kW PCSs are expected to contribute highly efficient operation of large scale PV plants for its life cycle.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115246096","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579240
N. Kawakami, K. Akatsu
This paper discusses a high frequency high power transformer to rotate an armature winding and the new motor drive system. The rotating transformer supplies the power from the movable part to the unmovable part by the wireless power transmission technique. The rotating transformer has an advantage of the maintenance-free as usual slip ring system has. Thus, we calculate its volume and weight from the control conditions and the theoretical formula. Moreover, we compare the weight and the size of the slip ring and the rotating transformer system. After that, we choose the best rotating transformer model and show the characteristics against to the variable load. Through the rotating transformer, single-phase power converts a three-phase power, the rectifier circuit independently drive the SR motor by a high frequency control.
{"title":"High power transformer and motor drive system design for an electric helicopter","authors":"N. Kawakami, K. Akatsu","doi":"10.1109/ECCE-ASIA.2013.6579240","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579240","url":null,"abstract":"This paper discusses a high frequency high power transformer to rotate an armature winding and the new motor drive system. The rotating transformer supplies the power from the movable part to the unmovable part by the wireless power transmission technique. The rotating transformer has an advantage of the maintenance-free as usual slip ring system has. Thus, we calculate its volume and weight from the control conditions and the theoretical formula. Moreover, we compare the weight and the size of the slip ring and the rotating transformer system. After that, we choose the best rotating transformer model and show the characteristics against to the variable load. Through the rotating transformer, single-phase power converts a three-phase power, the rectifier circuit independently drive the SR motor by a high frequency control.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122731258","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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