Pub Date : 2013-04-23DOI: 10.1109/PECI.2013.6506066
R. Ahmadi, A. Kashyap, Alberto Berrueta Irigoyen, A. Rayachoti, C. Wright, J. Kimball
This work proposes a new power conversion system suitable for supplying power to both ac and dc loads simultaneously from both ac sources, such as the power grid, and dc sources, such as a photovoltaic (PV) panel. First, an introduction of the motivation for proposing the new system and the objectives of the new system is given. Next, the new system and its building blocks are introduced. Then, the technical details about a built prototype conversion system are presented. Finally, a number of experimental results are provided to demonstrate the performance of the proposed system.
{"title":"Selective source power converter for improved photovoltaic power utilization","authors":"R. Ahmadi, A. Kashyap, Alberto Berrueta Irigoyen, A. Rayachoti, C. Wright, J. Kimball","doi":"10.1109/PECI.2013.6506066","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506066","url":null,"abstract":"This work proposes a new power conversion system suitable for supplying power to both ac and dc loads simultaneously from both ac sources, such as the power grid, and dc sources, such as a photovoltaic (PV) panel. First, an introduction of the motivation for proposing the new system and the objectives of the new system is given. Next, the new system and its building blocks are introduced. Then, the technical details about a built prototype conversion system are presented. Finally, a number of experimental results are provided to demonstrate the performance of the proposed system.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125182003","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506032
S. K. Kollimalla, M. Mishra
Maximum power point tracking (MPPT) techniques are used in photovoltaic (PV) systems to extract maximum power from the PV module. There are number of techniques available in literature. Perturb and observe (P &O) method is widely used because of its low-cost and ease of implementation. The P&O method oscillates close to maximum power point (MPP), when atmospheric conditions are constant or slowly varying. However, when irradiance and temperature are changing rapidly, this method fails to track MPP with rapid speed. In order to consider rapidly varying atmospheric conditions an adaptive control algorithm is proposed, by measuring the short circuit current at different irradiance levels and temperatures. In this proposed method current perturbation is considered instead of voltage perturbation. The proposed method has faster dynamics and improved stability compared to the conventional P&O method. The effectiveness of proposed MPPT algorithm is verified using digital simulations.
{"title":"Adaptive perturb & observe MPPT algorithm for photovoltaic system","authors":"S. K. Kollimalla, M. Mishra","doi":"10.1109/PECI.2013.6506032","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506032","url":null,"abstract":"Maximum power point tracking (MPPT) techniques are used in photovoltaic (PV) systems to extract maximum power from the PV module. There are number of techniques available in literature. Perturb and observe (P &O) method is widely used because of its low-cost and ease of implementation. The P&O method oscillates close to maximum power point (MPP), when atmospheric conditions are constant or slowly varying. However, when irradiance and temperature are changing rapidly, this method fails to track MPP with rapid speed. In order to consider rapidly varying atmospheric conditions an adaptive control algorithm is proposed, by measuring the short circuit current at different irradiance levels and temperatures. In this proposed method current perturbation is considered instead of voltage perturbation. The proposed method has faster dynamics and improved stability compared to the conventional P&O method. The effectiveness of proposed MPPT algorithm is verified using digital simulations.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114494779","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506037
P. Khayyer, U. Ozguner
Plug-in hybrid electric vehicles (PHEVs), as intermittent loads, create frequency disturbance in power system. The system needs to balance the power generation and demand. However, in regional smart grid systems fed by renewable energy sources and moveable loads, the power transfer through tie line interconnections is strongly coupled with system dynamics. This makes the frequency stability and control process very slow. In this paper, an overlapping decomposition technique of large-scale system control is used to decouple the renewable energy penetrated power system regions. A decentralized controller is then designed to maintain the frequency in a short time. Micro-hydro Simulation results demonstrate a fast frequency control process to regulate the system under input power variation from wind turbine and load from PHEVs.
{"title":"Decentralized control of smart grid with fixed and moving loads","authors":"P. Khayyer, U. Ozguner","doi":"10.1109/PECI.2013.6506037","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506037","url":null,"abstract":"Plug-in hybrid electric vehicles (PHEVs), as intermittent loads, create frequency disturbance in power system. The system needs to balance the power generation and demand. However, in regional smart grid systems fed by renewable energy sources and moveable loads, the power transfer through tie line interconnections is strongly coupled with system dynamics. This makes the frequency stability and control process very slow. In this paper, an overlapping decomposition technique of large-scale system control is used to decouple the renewable energy penetrated power system regions. A decentralized controller is then designed to maintain the frequency in a short time. Micro-hydro Simulation results demonstrate a fast frequency control process to regulate the system under input power variation from wind turbine and load from PHEVs.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129489990","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506063
S. Mohapatra, Hao Zhu, T. Overbye
This paper covers the reasons for studying transient behavior of electromechanical disturbances in electric power systems. It motivates the idea of using measurement data from transient events to infer as much as possible about the power system. As a starting point, frequency-domain analysis is explained and utilized. As an extension of the work in [2], two additional faults have been simulated with the 9-bus system and the frequency-domain analysis technique has been utilized to infer knowledge about the system. Frequency measurements from a simulation of an example large-scale interconnected power grid have also been analyzed. Some relevant literature and potentially useful data is highlighted. Lastly, the key take-aways are mentioned.
{"title":"Frequency-domain analysis of electromechanical disturbances in electric power systems","authors":"S. Mohapatra, Hao Zhu, T. Overbye","doi":"10.1109/PECI.2013.6506063","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506063","url":null,"abstract":"This paper covers the reasons for studying transient behavior of electromechanical disturbances in electric power systems. It motivates the idea of using measurement data from transient events to infer as much as possible about the power system. As a starting point, frequency-domain analysis is explained and utilized. As an extension of the work in [2], two additional faults have been simulated with the 9-bus system and the frequency-domain analysis technique has been utilized to infer knowledge about the system. Frequency measurements from a simulation of an example large-scale interconnected power grid have also been analyzed. Some relevant literature and potentially useful data is highlighted. Lastly, the key take-aways are mentioned.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129920187","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506054
P. Sotoodeh, R. Miller
This paper presents the design of a novel multi-level D-STATCOM inverter for renewable energy systems using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with FACTS capabilities to provide utilities with more knowledge about the distribution systems, specifically on end points. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to regulate the active and reactive power required by the grid. This inverter is capable of controlling active and reactive power by controlling its phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without any additional cost. Simulations of the proposed inverter, with 5 levels, have been completed in Matlab/Simulink. The simulation results validate the performance of the proposed control strategy.
{"title":"A new single-phase inverter with D-STATCOM capability for grid-connected small wind turbines","authors":"P. Sotoodeh, R. Miller","doi":"10.1109/PECI.2013.6506054","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506054","url":null,"abstract":"This paper presents the design of a novel multi-level D-STATCOM inverter for renewable energy systems using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with FACTS capabilities to provide utilities with more knowledge about the distribution systems, specifically on end points. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to regulate the active and reactive power required by the grid. This inverter is capable of controlling active and reactive power by controlling its phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without any additional cost. Simulations of the proposed inverter, with 5 levels, have been completed in Matlab/Simulink. The simulation results validate the performance of the proposed control strategy.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129071096","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506042
C. Choudhury, N. K. Deshmukh
As per IEC-60034-2-1, 2007, for a rotating electrical machine, the stray loss component increases with the decrease in the size of the machine. This causes a drastic reduction in the machine efficiency, especially in small a.c. motors. Using measures for reducing stray loss will greatly help in improving the efficiency of motors. This paper explores a novel method for reducing the stray loss in totally enclosed fan cooled (TEFC) induction motors. The concept of diamagnetic shielding has been used to reduce the stray loss occurring due to leakage of flux from stator's outer surface. Electromagnetic Analysis based on Finite Element Analysis (FEA) has been used extensively for this study. The effectiveness of the method has been highlighted by analyzing flux plots generated by electromagnetic software, Maxwell.
{"title":"A novel method for reduction of stray loss in induction motor","authors":"C. Choudhury, N. K. Deshmukh","doi":"10.1109/PECI.2013.6506042","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506042","url":null,"abstract":"As per IEC-60034-2-1, 2007, for a rotating electrical machine, the stray loss component increases with the decrease in the size of the machine. This causes a drastic reduction in the machine efficiency, especially in small a.c. motors. Using measures for reducing stray loss will greatly help in improving the efficiency of motors. This paper explores a novel method for reducing the stray loss in totally enclosed fan cooled (TEFC) induction motors. The concept of diamagnetic shielding has been used to reduce the stray loss occurring due to leakage of flux from stator's outer surface. Electromagnetic Analysis based on Finite Element Analysis (FEA) has been used extensively for this study. The effectiveness of the method has been highlighted by analyzing flux plots generated by electromagnetic software, Maxwell.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131257442","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506056
T. Naik, R. Wandhare, V. Agarwal
In a conventional grid connection of Photovoltaic (PV) system, a number of PV modules are connected in series and integrated to grid through a conventional two level inverter. Due to the impact of partial shading and module mismatch, such systems have a much lower yield compared to their maximum potential. To address this problem, direct connection of PV source to a three-level diode clamped inverter is considered in this paper, resulting in a single stage power conversion. A novel auxiliary converter is proposed that allows the two split halves of the PV source to be directly connected to the two dc-link capacitors, with each half operating at it's respective Maximum Power Point (MPP). This auxiliary converter can be rated for less power converter compare to the inverter capacity. The unequal MPP voltage of these split PV panels may cause detrimental effect on output current of inverter. To address this power quality issue, a modified switching algorithm is discussed to achieve voltage equalization across the split DC-Links of the multilevel inverter. Though the case of a split PV source (with two halves) has been considered, the proposed scheme is equally valid for a PV array split into more than two parts that may be suitable for a higher level Neutral Point Clamped (NPC) inverter. The proposed auxiliary converter and algorithm are evaluated and verified by simulation in MATLAB-Simulink.
{"title":"Three-level NPC inverter with novel voltage equalization for PV grid interface suitable for partially shaded conditions","authors":"T. Naik, R. Wandhare, V. Agarwal","doi":"10.1109/PECI.2013.6506056","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506056","url":null,"abstract":"In a conventional grid connection of Photovoltaic (PV) system, a number of PV modules are connected in series and integrated to grid through a conventional two level inverter. Due to the impact of partial shading and module mismatch, such systems have a much lower yield compared to their maximum potential. To address this problem, direct connection of PV source to a three-level diode clamped inverter is considered in this paper, resulting in a single stage power conversion. A novel auxiliary converter is proposed that allows the two split halves of the PV source to be directly connected to the two dc-link capacitors, with each half operating at it's respective Maximum Power Point (MPP). This auxiliary converter can be rated for less power converter compare to the inverter capacity. The unequal MPP voltage of these split PV panels may cause detrimental effect on output current of inverter. To address this power quality issue, a modified switching algorithm is discussed to achieve voltage equalization across the split DC-Links of the multilevel inverter. Though the case of a split PV source (with two halves) has been considered, the proposed scheme is equally valid for a PV array split into more than two parts that may be suitable for a higher level Neutral Point Clamped (NPC) inverter. The proposed auxiliary converter and algorithm are evaluated and verified by simulation in MATLAB-Simulink.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132566153","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506058
Soobae Kim, T. Overbye
Power system dynamic simulation demands substantial computation due to extensive interconnection among power systems. Traditionally, the computational burden has been reduced by using dynamic equivalent methodologies, such as modal, coherency and measurement-based. Measurement-based method replaces an external system with a simple equivalent and estimates its parameters through optimization method with measurement. However, the conventional method does not clearly present the model structure for the external equivalent. This ambiguity, then, may lead to poor performance of the equivalent. The proposed method uses generator equivalent model and shows how to choose a proper number of generators for the equivalent model structure using coherency concept. The approach preserves relevant modes from the external and thus enhances the simulation performance of the dynamic equivalent. Test results of a simple power system are presented and show a high level of accuracy of the proposed method.
{"title":"Enhanced measurement-based dynamic equivalence using coherency identification","authors":"Soobae Kim, T. Overbye","doi":"10.1109/PECI.2013.6506058","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506058","url":null,"abstract":"Power system dynamic simulation demands substantial computation due to extensive interconnection among power systems. Traditionally, the computational burden has been reduced by using dynamic equivalent methodologies, such as modal, coherency and measurement-based. Measurement-based method replaces an external system with a simple equivalent and estimates its parameters through optimization method with measurement. However, the conventional method does not clearly present the model structure for the external equivalent. This ambiguity, then, may lead to poor performance of the equivalent. The proposed method uses generator equivalent model and shows how to choose a proper number of generators for the equivalent model structure using coherency concept. The approach preserves relevant modes from the external and thus enhances the simulation performance of the dynamic equivalent. Test results of a simple power system are presented and show a high level of accuracy of the proposed method.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115443412","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506046
K. Pankaj, K. Ragavan
This research paper analyzes the effects of different winding layouts in an interior rotor, surface mounted, Permanent Magnet Brushless DC (PM BLDC) motor, with design parameters fixed. Generally the winding layout of the stator is fixed for a certain slot to pole configuration, but this paper explores the possibility of having suitable winding patterns as per need, using a concept of “Back EMF Wave Shaping”. It is shown that optimization of certain motor parameters, can be done by adjusting the winding arrangement.
{"title":"Analysis of back-EMF wave shaping on performance of PM brushless motor","authors":"K. Pankaj, K. Ragavan","doi":"10.1109/PECI.2013.6506046","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506046","url":null,"abstract":"This research paper analyzes the effects of different winding layouts in an interior rotor, surface mounted, Permanent Magnet Brushless DC (PM BLDC) motor, with design parameters fixed. Generally the winding layout of the stator is fixed for a certain slot to pole configuration, but this paper explores the possibility of having suitable winding patterns as per need, using a concept of “Back EMF Wave Shaping”. It is shown that optimization of certain motor parameters, can be done by adjusting the winding arrangement.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122145672","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 : 2013-04-23DOI: 10.1109/PECI.2013.6506026
Liang Pang, K. Kim
High-performance enhancement-mode (E-mode) AlGaN / GaN MOSHEMT has been achieved by CF4 plasma treatment and bimodal-gate-oxide deposition scheme. ALD-Al2O3 is utilized to prevent deep F- ion implantation into the 2DEG channel, while sputtered-SiO2, is employed to suppress the plasma-induced leakage current and increase the gate swing. Compared with the depletion-mode counterpart, thus-fabricated E-mode MOSHEMT exhibited 2.56 V shift in Vth, but only 8% degradation in Imax, demonstrating the promise of the bimodal-gate-oxide scheme for realizing E-mode operation of GaN-based MOSHEMTs.
采用CF4等离子体处理和双峰栅-氧化物沉积方案实现了高性能增强模式(E-mode) AlGaN / GaN MOSHEMT。ALD-Al2O3用于阻止深度F离子注入2DEG通道，而溅射sio2用于抑制等离子体诱导的泄漏电流和增加栅极摆幅。与耗尽模式MOSHEMT相比，由此制备的e模式MOSHEMT在Vth下的位移为2.56 V，而在Imax下的位移仅为8%，这表明双峰栅-氧化物方案有望实现gan基MOSHEMT的e模式工作。
{"title":"Fluoride-plasma-treated bimodal-gate-oxide ALGaN/GaN MOSHEMT for normally-off operation","authors":"Liang Pang, K. Kim","doi":"10.1109/PECI.2013.6506026","DOIUrl":"https://doi.org/10.1109/PECI.2013.6506026","url":null,"abstract":"High-performance enhancement-mode (E-mode) AlGaN / GaN MOSHEMT has been achieved by CF<sub>4</sub> plasma treatment and bimodal-gate-oxide deposition scheme. ALD-Al<sub>2</sub>O<sub>3</sub> is utilized to prevent deep F<sup>-</sup> ion implantation into the 2DEG channel, while sputtered-SiO<sub>2</sub>, is employed to suppress the plasma-induced leakage current and increase the gate swing. Compared with the depletion-mode counterpart, thus-fabricated E-mode MOSHEMT exhibited 2.56 V shift in V<sub>th</sub>, but only 8% degradation in I<sub>max</sub>, demonstrating the promise of the bimodal-gate-oxide scheme for realizing E-mode operation of GaN-based MOSHEMTs.","PeriodicalId":113021,"journal":{"name":"2013 IEEE Power and Energy Conference at Illinois (PECI)","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117222814","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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