Pub Date : 2000-12-04DOI: 10.1109/ISIE.2000.930532
A. Hu, J. Boys, G. Covic
ZVS (zero voltage switching) is critical for the reliable operation of normal current fed DC-AC resonant converters. In the steady state, ZVS can be achieved by many available techniques such as PLL, VCO and other integral controllers. However, during the transient process like start up, to achieve ZVS is not an easy task for these controllers and consequently switch failure may occur. Based on numerical and analytical analyses, this paper proposes a novel method using an initially forced DC current to achieve ZVS during start up. Start up conditions are discussed and complete dynamic ZVS is achieved. Considering the ramp up delay of the DC power supply, the start up can be controlled completely overshoot free at no extra cost. The validity of this method has been proven with PSpice simulations and experimental results.
{"title":"Dynamic ZVS direct on-line start up of current fed resonant converter using initially forced DC current","authors":"A. Hu, J. Boys, G. Covic","doi":"10.1109/ISIE.2000.930532","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930532","url":null,"abstract":"ZVS (zero voltage switching) is critical for the reliable operation of normal current fed DC-AC resonant converters. In the steady state, ZVS can be achieved by many available techniques such as PLL, VCO and other integral controllers. However, during the transient process like start up, to achieve ZVS is not an easy task for these controllers and consequently switch failure may occur. Based on numerical and analytical analyses, this paper proposes a novel method using an initially forced DC current to achieve ZVS during start up. Start up conditions are discussed and complete dynamic ZVS is achieved. Considering the ramp up delay of the DC power supply, the start up can be controlled completely overshoot free at no extra cost. The validity of this method has been proven with PSpice simulations and experimental results.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129067285","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930512
J. Pacas, A. John, T. Eutebach
The paper deals with the identification and damping of torsional oscillations in high dynamic industrial drives. Based on a model with two concentrated masses with an elastic coupling and driven by a field-orientated induction machine, methods for the identification and damping of torsional oscillations were developed. On a downscaled laboratory setup, well-known and newly developed procedures for the identification of the resonance frequencies were compared regarding their effectiveness and effort of implementation and under consideration of an automatic identification. Besides, experimental results of several methods for the active damping of the torsional oscillations are presented. They were completed by measurements carried out on a high dynamic industrial drive for a cross cutter for paper (sheeter).
{"title":"Automatic identification and damping of torsional vibrations in high-dynamic-drives","authors":"J. Pacas, A. John, T. Eutebach","doi":"10.1109/ISIE.2000.930512","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930512","url":null,"abstract":"The paper deals with the identification and damping of torsional oscillations in high dynamic industrial drives. Based on a model with two concentrated masses with an elastic coupling and driven by a field-orientated induction machine, methods for the identification and damping of torsional oscillations were developed. On a downscaled laboratory setup, well-known and newly developed procedures for the identification of the resonance frequencies were compared regarding their effectiveness and effort of implementation and under consideration of an automatic identification. Besides, experimental results of several methods for the active damping of the torsional oscillations are presented. They were completed by measurements carried out on a high dynamic industrial drive for a cross cutter for paper (sheeter).","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129955220","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930482
Qi-Wen Yang, Jing-ping Jiang, Guo Chen
In order to enhance the optimization efficiency, it's important for genetic algorithms (GAs) to select optimal control parameters. But the theory behind parameter setting for a GA gives little guidance for their selection. We have being selected the control parameters for GAs only by trials so far. In this paper, we discuss the function of genetic operators and present the conception of natality of schema (NS). We put forward an approach to estimating the optimal ranges of the control parameters for GAs by utilizing the NS. The approach is proven effectively by a genetic algorithm based on Boolean operators (GABO) which is proposed in this paper.
{"title":"How to select optimal control parameters for genetic algorithms","authors":"Qi-Wen Yang, Jing-ping Jiang, Guo Chen","doi":"10.1109/ISIE.2000.930482","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930482","url":null,"abstract":"In order to enhance the optimization efficiency, it's important for genetic algorithms (GAs) to select optimal control parameters. But the theory behind parameter setting for a GA gives little guidance for their selection. We have being selected the control parameters for GAs only by trials so far. In this paper, we discuss the function of genetic operators and present the conception of natality of schema (NS). We put forward an approach to estimating the optimal ranges of the control parameters for GAs by utilizing the NS. The approach is proven effectively by a genetic algorithm based on Boolean operators (GABO) which is proposed in this paper.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121035331","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930474
J. Holtz
Controlled induction motor drives without mechanical sensors for speed or motor shaft position have the attraction of low cost and high reliability. The identification of rotor speed is generally based on measured terminal voltages and currents. Dynamic models are used to estimate the magnitude and spatial orientation of the fundamental magnetic flux waves in the stator or in the rotor. Open loop estimators and closed loop observers differ with respect to accuracy, robustness, and sensitivity against model parameter variations. Dynamic performance and steady-state speed accuracy in the low speed range is achieved by exploiting parasitic effects of the machine. The overview in this paper uses signal flow graphs of complex space vector quantities to provide an insightful description of the systems used in sensorless control of induction motors.
{"title":"Sensorless control of induction motors-performance and limitations","authors":"J. Holtz","doi":"10.1109/ISIE.2000.930474","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930474","url":null,"abstract":"Controlled induction motor drives without mechanical sensors for speed or motor shaft position have the attraction of low cost and high reliability. The identification of rotor speed is generally based on measured terminal voltages and currents. Dynamic models are used to estimate the magnitude and spatial orientation of the fundamental magnetic flux waves in the stator or in the rotor. Open loop estimators and closed loop observers differ with respect to accuracy, robustness, and sensitivity against model parameter variations. Dynamic performance and steady-state speed accuracy in the low speed range is achieved by exploiting parasitic effects of the machine. The overview in this paper uses signal flow graphs of complex space vector quantities to provide an insightful description of the systems used in sensorless control of induction motors.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124117772","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930469
J. Pacas
The substantial developments in power electronics, motor technology and microelectronics has brought about an enormous momentum in the area of drives. In the past, drive technology was dominated by DC-drives and in special cases by BLDC-motors. Many applications in production machines and processes demand intelligent drives with new actuators and sophisticated control strategies. Departing from the different industrial applications the main electrical and mechanical requirements and design criteria for drives are explained. Further, the different technical solutions and their components are discussed: power electronics, machines, sensors, actuators, control strategies and communication. For each subsystem the special requirements of drives in the field of industrial automation and the corresponding technologies are explained considering the state of the art and the ongoing developments. Motion control, multi-axis systems and communication between the control levels and the intelligent drives are considered as well. Digital communications systems are presented as a necessary interface for this kind of drive. In a system comparison the capabilities and drawbacks of each system in the different practical applications are explained. The tutorial is intended as a complete survey on the topic and is addressed to engineers involved in the practical design of industrial drives in the application of drives for new high demanding machines and processes.
{"title":"Drives in the automation","authors":"J. Pacas","doi":"10.1109/ISIE.2000.930469","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930469","url":null,"abstract":"The substantial developments in power electronics, motor technology and microelectronics has brought about an enormous momentum in the area of drives. In the past, drive technology was dominated by DC-drives and in special cases by BLDC-motors. Many applications in production machines and processes demand intelligent drives with new actuators and sophisticated control strategies. Departing from the different industrial applications the main electrical and mechanical requirements and design criteria for drives are explained. Further, the different technical solutions and their components are discussed: power electronics, machines, sensors, actuators, control strategies and communication. For each subsystem the special requirements of drives in the field of industrial automation and the corresponding technologies are explained considering the state of the art and the ongoing developments. Motion control, multi-axis systems and communication between the control levels and the intelligent drives are considered as well. Digital communications systems are presented as a necessary interface for this kind of drive. In a system comparison the capabilities and drawbacks of each system in the different practical applications are explained. The tutorial is intended as a complete survey on the topic and is addressed to engineers involved in the practical design of industrial drives in the application of drives for new high demanding machines and processes.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130642711","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930486
J. Cortés
The estimation of electrical appliances demand represents in the electrical sector an important point as part of the operation and planning processes. Part of the revenues are obtained from the tariffs that consumers pay, and represents resources for financing the growth and operation of the electrical sector. This paper shows a methodology based on evolutionary programming for estimating the demand for each electrical appliance in a household based on the total demand, in contrast with other more restricted approaches, where they obtained demand samples for each appliance in any time period, and then estimate the true demand. An example is presented and discussed.
{"title":"Electrical appliances duty cycles obtained from total demand of household using evolutionary programming","authors":"J. Cortés","doi":"10.1109/ISIE.2000.930486","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930486","url":null,"abstract":"The estimation of electrical appliances demand represents in the electrical sector an important point as part of the operation and planning processes. Part of the revenues are obtained from the tariffs that consumers pay, and represents resources for financing the growth and operation of the electrical sector. This paper shows a methodology based on evolutionary programming for estimating the demand for each electrical appliance in a household based on the total demand, in contrast with other more restricted approaches, where they obtained demand samples for each appliance in any time period, and then estimate the true demand. An example is presented and discussed.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131729661","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930348
E. Wiechmann, A. J. Pagliero, G. A. Vidal
The most used technology for obtaining pure copper in oxide ore copper mining is LIX-SX-EW (leaching-solvent extraction-electrowinning). In this process, the maximum allowable current which does not lead to electrode short-circuit sets the production limit. This is a major drawback if equipotential bars to connect the electrodes are used. This common practice exhibits a high dispersion value for the current distribution. This paper presents a connection arrangement of the electrowinning cells to balance cathode currents. The new connection drives the current through more balanced resistivity channels. Moreover, the uniform level of current achieved produces a more standardized product. Both, chemical and physical quality of cathodes is improved. Finally, the approach limits anode-cathode overcurrent preventing short circuit formation. Thus, current efficiency and plant operation are also improved.
{"title":"Multicircuit approach for electrolytic cells, a novel method to force current balance in electrowinning plants","authors":"E. Wiechmann, A. J. Pagliero, G. A. Vidal","doi":"10.1109/ISIE.2000.930348","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930348","url":null,"abstract":"The most used technology for obtaining pure copper in oxide ore copper mining is LIX-SX-EW (leaching-solvent extraction-electrowinning). In this process, the maximum allowable current which does not lead to electrode short-circuit sets the production limit. This is a major drawback if equipotential bars to connect the electrodes are used. This common practice exhibits a high dispersion value for the current distribution. This paper presents a connection arrangement of the electrowinning cells to balance cathode currents. The new connection drives the current through more balanced resistivity channels. Moreover, the uniform level of current achieved produces a more standardized product. Both, chemical and physical quality of cathodes is improved. Finally, the approach limits anode-cathode overcurrent preventing short circuit formation. Thus, current efficiency and plant operation are also improved.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134474274","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930397
M.H. Lee, K. Son, S.H. Han, J.M. Lee, M.C. Lee, J.W. Choi, H. N. Joo, Y. Chang
This paper presents an intelligent robot control system using an off-line programming to teach precise assembly task of electronic components in a flexible way. The task investigated consists of three jobs: heat caulking test, soldering on a circuit board, and checking of soldering defects on the back cover of a camera. This study investigates the remodelling of the most complicated cell in terms of accuracy and fault rate among the twelve cells in a camera back-cover assembly line. We have attempted to enhance soldering quality, to add task flexibility, to reduce failure rate, and to increase product reliability. This study modifies the cell structure, changes robots, improves soldering condition, implements the real-time control of assembly with vision data, and realizes an easier task teaching off-line programming.
{"title":"Development of an automated system for soldering and the solder inspection of an assembly line","authors":"M.H. Lee, K. Son, S.H. Han, J.M. Lee, M.C. Lee, J.W. Choi, H. N. Joo, Y. Chang","doi":"10.1109/ISIE.2000.930397","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930397","url":null,"abstract":"This paper presents an intelligent robot control system using an off-line programming to teach precise assembly task of electronic components in a flexible way. The task investigated consists of three jobs: heat caulking test, soldering on a circuit board, and checking of soldering defects on the back cover of a camera. This study investigates the remodelling of the most complicated cell in terms of accuracy and fault rate among the twelve cells in a camera back-cover assembly line. We have attempted to enhance soldering quality, to add task flexibility, to reduce failure rate, and to increase product reliability. This study modifies the cell structure, changes robots, improves soldering condition, implements the real-time control of assembly with vision data, and realizes an easier task teaching off-line programming.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"74 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132476885","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930368
Marko Hočevar, M. Novák, B. Širok
An experimental study of the turbulent mixing flow in the wake of a prismatic bluff body was made in a nonreturn subsonic wind tunnel (Re/sub b/=4300) using flow visualization and a digital image-processing technique. A high-speed camera was used to capture smoke visualization images of the turbulent mixing flow structures. From the grey level intensity of selected image windows, using a radial basis neural network, grey levels of the neighbouring locations were calculated and compared to the measured intensity. As an input area, part of the image was used, located upstream of the prediction area. Prediction was based on history of 6 successive images. Neural network was trained where first 200 images of the same sequence were applied. Quality of prediction depends on now properties at a given location and on the distance from the input area. The quality of prediction at various locations corresponds well to the intensity of concentration fluctuations. Power spectra of the predicted and actual image sequence are compared.
{"title":"Prediction of the grey level intensity in selected windows of image sequence using radial basis network","authors":"Marko Hočevar, M. Novák, B. Širok","doi":"10.1109/ISIE.2000.930368","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930368","url":null,"abstract":"An experimental study of the turbulent mixing flow in the wake of a prismatic bluff body was made in a nonreturn subsonic wind tunnel (Re/sub b/=4300) using flow visualization and a digital image-processing technique. A high-speed camera was used to capture smoke visualization images of the turbulent mixing flow structures. From the grey level intensity of selected image windows, using a radial basis neural network, grey levels of the neighbouring locations were calculated and compared to the measured intensity. As an input area, part of the image was used, located upstream of the prediction area. Prediction was based on history of 6 successive images. Neural network was trained where first 200 images of the same sequence were applied. Quality of prediction depends on now properties at a given location and on the distance from the input area. The quality of prediction at various locations corresponds well to the intensity of concentration fluctuations. Power spectra of the predicted and actual image sequence are compared.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"127 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131434594","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 : 2000-12-04DOI: 10.1109/ISIE.2000.930533
C. Brañas, F. Azcondo, S. Bracho
This paper proposes a design method for a class D series-parallel (LC/sub s/C/sub p/) resonant inverter suitable to drive high-intensity discharge lamps. The high voltage needed to achieve the ignition of the lamp is reached by using the gain voltage of the resonant LC/sub s/C/sub p/ network with no auxiliary circuits for this purpose. By means of a soft start-up sequence the maximum voltage and current stress are maintained below prefixed values. In steady state, the operation point is calculated to limit the maximum power that the inverter delivers to the lamp. In this way, the variation of the lamp power caused by the lamp aging is limited in order to fulfil the standard. This design results in cost-effective circuits, simplifying the DC/AC power stage of an electronic ballast. The experimental results are given for two similar 100 W high-pressure sodium lamps with different aging.
{"title":"Class d LC/sub s/C/sub p/ series-parallel resonant inverter with inherent maximum output power suitable for driving HPS lamps","authors":"C. Brañas, F. Azcondo, S. Bracho","doi":"10.1109/ISIE.2000.930533","DOIUrl":"https://doi.org/10.1109/ISIE.2000.930533","url":null,"abstract":"This paper proposes a design method for a class D series-parallel (LC/sub s/C/sub p/) resonant inverter suitable to drive high-intensity discharge lamps. The high voltage needed to achieve the ignition of the lamp is reached by using the gain voltage of the resonant LC/sub s/C/sub p/ network with no auxiliary circuits for this purpose. By means of a soft start-up sequence the maximum voltage and current stress are maintained below prefixed values. In steady state, the operation point is calculated to limit the maximum power that the inverter delivers to the lamp. In this way, the variation of the lamp power caused by the lamp aging is limited in order to fulfil the standard. This design results in cost-effective circuits, simplifying the DC/AC power stage of an electronic ballast. The experimental results are given for two similar 100 W high-pressure sodium lamps with different aging.","PeriodicalId":298625,"journal":{"name":"ISIE'2000. Proceedings of the 2000 IEEE International Symposium on Industrial Electronics (Cat. No.00TH8543)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123936378","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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