Pub Date : 2002-12-10DOI: 10.1109/IAS.2002.1044118
L. Pereira, V. Canalli
The paper describes the design and parameter calculation of a five-phase permanent magnet synchronous machine intended for operation as generator connected to the load over a rectifier bridge. The main parameters and machine dimensions are determined using the finite element method in 2 dimensions. Calculated no-load induced voltage and inductances are compared with measured values obtained from a prototype machine. A circuit based mathematical model is also developed and simulated using Matlab/Simulink and the results are used to determine the machine performance as generator. The simulation results are checked versus measured values, and a good agreement between the simulation and measurements was observed. The implemented model gives results with sufficient accuracy, allowing to determine the machine behavior in early design stages. The method described here can be successfully applied for designing and performance calculation of high phase machine.
{"title":"Five-phase permanent magnet synchronous machine operating as generator design, parameter determination by FEM and performance","authors":"L. Pereira, V. Canalli","doi":"10.1109/IAS.2002.1044118","DOIUrl":"https://doi.org/10.1109/IAS.2002.1044118","url":null,"abstract":"The paper describes the design and parameter calculation of a five-phase permanent magnet synchronous machine intended for operation as generator connected to the load over a rectifier bridge. The main parameters and machine dimensions are determined using the finite element method in 2 dimensions. Calculated no-load induced voltage and inductances are compared with measured values obtained from a prototype machine. A circuit based mathematical model is also developed and simulated using Matlab/Simulink and the results are used to determine the machine performance as generator. The simulation results are checked versus measured values, and a good agreement between the simulation and measurements was observed. The implemented model gives results with sufficient accuracy, allowing to determine the machine behavior in early design stages. The method described here can be successfully applied for designing and performance calculation of high phase machine.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116372672","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 : 2002-12-10DOI: 10.1109/IAS.2002.1043831
J. Yamada, Y. Yu, Y. Ishimura, J. Donlon, E. Motto
A new 5th generation IGBT module with low turn-off energy has been developed. The module utilizes IGBT chips optimized for high frequency industrial power supplies in applications such as X-ray, MRI (magnetic resonance imaging), and induction heating. This technology is designed to provide a simplified cost effective alternative to parallel discrete MOSFETs in these applications.
{"title":"Low turn-off switching energy 1200 V IGBT module","authors":"J. Yamada, Y. Yu, Y. Ishimura, J. Donlon, E. Motto","doi":"10.1109/IAS.2002.1043831","DOIUrl":"https://doi.org/10.1109/IAS.2002.1043831","url":null,"abstract":"A new 5th generation IGBT module with low turn-off energy has been developed. The module utilizes IGBT chips optimized for high frequency industrial power supplies in applications such as X-ray, MRI (magnetic resonance imaging), and induction heating. This technology is designed to provide a simplified cost effective alternative to parallel discrete MOSFETs in these applications.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127119007","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 : 2002-12-10DOI: 10.1109/IAS.2002.1043789
Jinghai Zhou, F. Tao, F. Lee, N. Onishi, M. Okawa
A high power density electronic ballast circuit for high intensity discharge (HID) lamp is proposed. Approaches to achieve high power density are studied. Topologically, the zero-voltage-switching quasi-square-wave concept is adopted when developing the high frequency high efficiency DC/DC front-end converter for the ballast based on the semiconductor loss analysis. On the other hand, a PCB level packaging method is proposed to deal with the thermal related issues, which further improves the power density of the system. A prototype is developed, with a maximum efficiency of 93.3% and the power density of 38.7 W/inch/sup 3/.
{"title":"High power density electronic ballast for HID lamps","authors":"Jinghai Zhou, F. Tao, F. Lee, N. Onishi, M. Okawa","doi":"10.1109/IAS.2002.1043789","DOIUrl":"https://doi.org/10.1109/IAS.2002.1043789","url":null,"abstract":"A high power density electronic ballast circuit for high intensity discharge (HID) lamp is proposed. Approaches to achieve high power density are studied. Topologically, the zero-voltage-switching quasi-square-wave concept is adopted when developing the high frequency high efficiency DC/DC front-end converter for the ballast based on the semiconductor loss analysis. On the other hand, a PCB level packaging method is proposed to deal with the thermal related issues, which further improves the power density of the system. A prototype is developed, with a maximum efficiency of 93.3% and the power density of 38.7 W/inch/sup 3/.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127558604","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 : 2002-12-10DOI: 10.1109/IAS.2002.1042780
Fengxiang Wang, Chengwu Lin, J. Zhu, Longya Xu
A doubly-fed machine adjustable speed system normally needs a bi-directional converter. Not only the control technique is complicated but also the system cost is rather high. In this paper, a chopping and doubly-fed adjusting speed control strategy is proposed based on the variable speed principle of the doubly-fed machine. The circuit topology, fulfilling combined functions of a rectifier, chopper and inverter, is described. The control algorithms in chopping and doubly-fed modes for adjustable speed operation based on the Intel 8XC196MC single-chip-computer are derived. The Experimental results show the feasibility of the proposed scheme. Advantages of using the proposed system include a relatively inexpensive multi-functional converter, soft-starting, adjustable speed operation through chopping and doubly-fed adjustable speed modes below or above synchronous speed with reactive power regulation.
{"title":"A chopping and doubly-fed adjustable speed system without bi-directional converter","authors":"Fengxiang Wang, Chengwu Lin, J. Zhu, Longya Xu","doi":"10.1109/IAS.2002.1042780","DOIUrl":"https://doi.org/10.1109/IAS.2002.1042780","url":null,"abstract":"A doubly-fed machine adjustable speed system normally needs a bi-directional converter. Not only the control technique is complicated but also the system cost is rather high. In this paper, a chopping and doubly-fed adjusting speed control strategy is proposed based on the variable speed principle of the doubly-fed machine. The circuit topology, fulfilling combined functions of a rectifier, chopper and inverter, is described. The control algorithms in chopping and doubly-fed modes for adjustable speed operation based on the Intel 8XC196MC single-chip-computer are derived. The Experimental results show the feasibility of the proposed scheme. Advantages of using the proposed system include a relatively inexpensive multi-functional converter, soft-starting, adjustable speed operation through chopping and doubly-fed adjustable speed modes below or above synchronous speed with reactive power regulation.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127451764","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 : 2002-12-10DOI: 10.1109/IAS.2002.1044102
Xuezhi Yang, G. Pang, N. Yung
This paper proposes a new method for fabric defect classification by incorporating the design of a wavelet frames based feature extractor with the design of a Euclidean distance based classifier. Channel variances at the outputs of the wavelet frame decomposition are used to characterize each nonoverlapping window of the fabric image. A feature extractor using linear transformation matrix is further employed to extract the classification-oriented features. With a Euclidean distance based classifier, each nonoverlapping window of the fabric image is then assigned to its corresponding category. Minimization of the classification error is achieved by incorporating the design of the feature extractor with the design of the classifier based on minimum classification error (MCE) training method. The proposed method has been evaluated on the classification of 329 defect samples containing nine classes of fabric defects, and 328 nondefect samples, where 93.1% classification accuracy has been achieved.
{"title":"Fabric defect classification using wavelet frames and minimum classification error training","authors":"Xuezhi Yang, G. Pang, N. Yung","doi":"10.1109/IAS.2002.1044102","DOIUrl":"https://doi.org/10.1109/IAS.2002.1044102","url":null,"abstract":"This paper proposes a new method for fabric defect classification by incorporating the design of a wavelet frames based feature extractor with the design of a Euclidean distance based classifier. Channel variances at the outputs of the wavelet frame decomposition are used to characterize each nonoverlapping window of the fabric image. A feature extractor using linear transformation matrix is further employed to extract the classification-oriented features. With a Euclidean distance based classifier, each nonoverlapping window of the fabric image is then assigned to its corresponding category. Minimization of the classification error is achieved by incorporating the design of the feature extractor with the design of the classifier based on minimum classification error (MCE) training method. The proposed method has been evaluated on the classification of 329 defect samples containing nine classes of fabric defects, and 328 nondefect samples, where 93.1% classification accuracy has been achieved.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133572763","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 : 2002-12-10DOI: 10.1109/IAS.2002.1044103
K. Haeiwa, T. Yamashita, Y. Takeuchi, Y. Toba, S. Torihata, M. Onizawa
An evolutional optical RF-TV signal sensing and transmitting facilities were constructed and employed for a new type of TV relaying station. A LiNbO/sub 3/ optical modulator of Mach-Zehnder type at 1.3 /spl mu/m, which was used to modulate a light beam at 1.3 /spl mu/m with digital terrestrial television (OFDM) signals at a 470 MHz through 770 MHz band with a power level of 36 dB /spl mu/V obtained from a UHF-TV receiving antenna in the receiving facilities, was newly used to send these RF-TV signals to the transmitting facilities located up to 6 km apart from the receiving point. The system operation was satisfactory.
{"title":"Optical RF-TV signal sensing and transmission for terrestrial TV relaying stations","authors":"K. Haeiwa, T. Yamashita, Y. Takeuchi, Y. Toba, S. Torihata, M. Onizawa","doi":"10.1109/IAS.2002.1044103","DOIUrl":"https://doi.org/10.1109/IAS.2002.1044103","url":null,"abstract":"An evolutional optical RF-TV signal sensing and transmitting facilities were constructed and employed for a new type of TV relaying station. A LiNbO/sub 3/ optical modulator of Mach-Zehnder type at 1.3 /spl mu/m, which was used to modulate a light beam at 1.3 /spl mu/m with digital terrestrial television (OFDM) signals at a 470 MHz through 770 MHz band with a power level of 36 dB /spl mu/V obtained from a UHF-TV receiving antenna in the receiving facilities, was newly used to send these RF-TV signals to the transmitting facilities located up to 6 km apart from the receiving point. The system operation was satisfactory.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127250439","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 : 2002-12-10DOI: 10.1109/IAS.2002.1043819
Terrence J. Summers, Robert E. Betz
Current control in inverter driven machine systems is arguably the most important part of the control system. If accurate and rapid current control is achieved then, given the correct reference currents, fast and accurate torque control can be achieved. Unfortunately the implementation of current control in power electronic systems is not ideal. Practical effects can have a significant influence on its performance. This paper examines one of these effects, dead-time, and considers the influence it has on the performance of predictive current controllers (PCCs). The paper presents analysis that shows that PCC implicitly compensates for voltage loss due to dead-time. Also a modified PCC is introduced that reduces the zero current clamp problem caused by dead-time. Simulation and experimental results are presented to verify the analysis and confirm the performance of the new algorithm.
{"title":"Dead-time issues in predictive current control","authors":"Terrence J. Summers, Robert E. Betz","doi":"10.1109/IAS.2002.1043819","DOIUrl":"https://doi.org/10.1109/IAS.2002.1043819","url":null,"abstract":"Current control in inverter driven machine systems is arguably the most important part of the control system. If accurate and rapid current control is achieved then, given the correct reference currents, fast and accurate torque control can be achieved. Unfortunately the implementation of current control in power electronic systems is not ideal. Practical effects can have a significant influence on its performance. This paper examines one of these effects, dead-time, and considers the influence it has on the performance of predictive current controllers (PCCs). The paper presents analysis that shows that PCC implicitly compensates for voltage loss due to dead-time. Also a modified PCC is introduced that reduces the zero current clamp problem caused by dead-time. Simulation and experimental results are presented to verify the analysis and confirm the performance of the new algorithm.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116696682","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 : 2002-12-10DOI: 10.1109/IAS.2002.1042689
M. Costa, Á. Seidel, F. Bisogno, R. D. do Prado
This paper presents a self-oscillating dimmable electronic ballast to supply two independent lamps. A simple modification in the driver circuit allows dimming of the lamps; this modification consists of only two additional low power passive components. The describing function method and the extended Nyquist criterion are used in the analysis and design. An improved arrangement of the lamps in the half-bridge topology is done, putting one lamp in each switch of the converter. The advantages of this new arrangement are: if one lamp is damaged, the other keeps working; it has an efficiency improvement when compared to ballasts that supply only one lamp; and the voltage supported by the switches is smaller when compared to the conventional ballasts which supply two lamps in series. Dim feature allows correcting the switching frequency when one of the lamps is out of the circuit.
{"title":"Self-oscillating dimmable electronic ballast to supply two independent lamps","authors":"M. Costa, Á. Seidel, F. Bisogno, R. D. do Prado","doi":"10.1109/IAS.2002.1042689","DOIUrl":"https://doi.org/10.1109/IAS.2002.1042689","url":null,"abstract":"This paper presents a self-oscillating dimmable electronic ballast to supply two independent lamps. A simple modification in the driver circuit allows dimming of the lamps; this modification consists of only two additional low power passive components. The describing function method and the extended Nyquist criterion are used in the analysis and design. An improved arrangement of the lamps in the half-bridge topology is done, putting one lamp in each switch of the converter. The advantages of this new arrangement are: if one lamp is damaged, the other keeps working; it has an efficiency improvement when compared to ballasts that supply only one lamp; and the voltage supported by the switches is smaller when compared to the conventional ballasts which supply two lamps in series. Dim feature allows correcting the switching frequency when one of the lamps is out of the circuit.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"55 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131407985","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 : 2002-12-10DOI: 10.1109/IAS.2002.1042711
N. Vishwanathan, V. Ramanarayanan
High voltage power supplies with pulse load (125 kHz and 10 % duty cycle) are investigated which are of interest for applications like radar power supplies with an output voltage of 22 kV. The performance specifications with this type of power supplies are very stringent demanding tight regulation (<0.01 %) and high efficiency (>85 %). This paper proposes a methodology to tackle the problems associated with this type of application. A phase-modulated series resonant converter with ZVS is used as the power converter. Average value of the rectified tank current is controlled to regulate the output voltage. Synchronization of converter switching with load pulses enables the converter to switch at half the load switching frequency. Low switching frequency helps in ensuring safety of HV transformer insulation and reduction of losses due to skin & proximity effect. Average current mode control gives excellent dynamic response with simple closed loop design.
{"title":"Average current mode control of high voltage DC power supply for pulsed load application","authors":"N. Vishwanathan, V. Ramanarayanan","doi":"10.1109/IAS.2002.1042711","DOIUrl":"https://doi.org/10.1109/IAS.2002.1042711","url":null,"abstract":"High voltage power supplies with pulse load (125 kHz and 10 % duty cycle) are investigated which are of interest for applications like radar power supplies with an output voltage of 22 kV. The performance specifications with this type of power supplies are very stringent demanding tight regulation (<0.01 %) and high efficiency (>85 %). This paper proposes a methodology to tackle the problems associated with this type of application. A phase-modulated series resonant converter with ZVS is used as the power converter. Average value of the rectified tank current is controlled to regulate the output voltage. Synchronization of converter switching with load pulses enables the converter to switch at half the load switching frequency. Low switching frequency helps in ensuring safety of HV transformer insulation and reduction of losses due to skin & proximity effect. Average current mode control gives excellent dynamic response with simple closed loop design.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132547970","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 : 2002-12-10DOI: 10.1109/IAS.2002.1043807
P. Loh, D. G. Holmes, Y. Fukuta, T. Lipo
This paper presents carrier-based modulation strategies for cascaded multilevel inverters that substantially eliminate common mode voltage on the output phases. The paper begins by developing generic multilevel inverter reference waveforms that use only "allowed" space vectors to achieve reduced common mode voltage. A graphical technique is then proposed that allows various carrier disposition modulation strategies for a diode clamped inverter to be converted to equivalent modulation of a cascaded inverter for any fundamental reference waveform. This graphical technique is confirmed for both alternative phase opposition disposition (APOD) and phase disposition (PD) equivalent modulation of a cascaded inverter, and is then used to create reduced common mode modulation strategies for cascaded inverters from their equivalent counterparts for diode-clamped inverters under both continuous and discontinuous switching conditions. The strategies have been confirmed by both simulation and experimental results obtained using a cascaded five-level inverter.
{"title":"Reduced common mode carrier-based modulation strategies for cascaded multilevel inverters","authors":"P. Loh, D. G. Holmes, Y. Fukuta, T. Lipo","doi":"10.1109/IAS.2002.1043807","DOIUrl":"https://doi.org/10.1109/IAS.2002.1043807","url":null,"abstract":"This paper presents carrier-based modulation strategies for cascaded multilevel inverters that substantially eliminate common mode voltage on the output phases. The paper begins by developing generic multilevel inverter reference waveforms that use only \"allowed\" space vectors to achieve reduced common mode voltage. A graphical technique is then proposed that allows various carrier disposition modulation strategies for a diode clamped inverter to be converted to equivalent modulation of a cascaded inverter for any fundamental reference waveform. This graphical technique is confirmed for both alternative phase opposition disposition (APOD) and phase disposition (PD) equivalent modulation of a cascaded inverter, and is then used to create reduced common mode modulation strategies for cascaded inverters from their equivalent counterparts for diode-clamped inverters under both continuous and discontinuous switching conditions. The strategies have been confirmed by both simulation and experimental results obtained using a cascaded five-level inverter.","PeriodicalId":202482,"journal":{"name":"Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128419266","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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