Electrical Engineering & Electromechanics最新文献

{"title":"POWERFUL HIGH-CURRENT GENERATOR OF MICROSECOND VOLTAGE PULSES WITH VOLTAGE AMPLITUDE UP TO ±2 MV AND CURRENT AMPLITUDE UP TO ±150 kA WITH ELECTRIC ENERGY STORED IN CAPACITORS UP TO 1 MJ","authors":"M. I. Baranov, S. Buriakovskyi, V. Kniaziev","doi":"10.20998/2074-272x.2020.5.08","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.5.08","url":null,"abstract":"Purpose. Development and evaluation, on the basis of existing ultra-high-voltage generator of pulsed voltages and currents of GINT-4 type, of the new scheme of design of its charging-discharging circuit (CDC), and creation of modernized powerful ultra-high-voltage high-current generator of GINT-2 type to form microsecond voltage pulses with amplitudes up to ±2 MV and current with amplitude up to ±150 kA in the electrical load, with electrical energy stored in its capacitive energy storage (CES) up to 1 MJ. Methodology. Fundamentals of theoretical and applied electrical engineering, electrical power engineering, electrophysical principles of high-voltage and high pulsed current engineering, fundamentals of electromagnetic compatibility (EMC), instrument engineering, high-voltage instrumentation and standardization. Results. The new scheme of design of CDC of the modernized powerful ultra-high-voltage, heavy-current generator of GINT-2 type of outdoor placement, that allows obtaining, with preservation of the main electrotechnical elemental base of existing powerful prototype generator GINT-4 (rated output voltage ±4 MV with rated electrical energy stored in CES of 1 MJ and maximal amplitude of output current pulse in electrical load up to ±75 kA) pulses of current of microsecond duration with doubled amplitude (up to ±150 kA) in the long (from 1 to 4 m length) air gap of standard two-electrode discharging «needle-plane» system, in comparison with parameters of current pulses with amplitudes up to ±75 kA that are formed in the discharging circuit of generator of GINT-4 type with the use of the analogous air discharging system, has been developed. Experimental evaluations of the developed new discharging circuit in CDC of the modernized generator of GINT-4 type has been performed in field conditions, and its advantages over the old discharging circuit in composition of CDC of generator of GINT-4 type have been shown. Calculated evaluations of rise rates of high pulsed current (HPC) in plasma channel of air spark discharge of CES with energy up to 1 MJ of generator of GINT-2 type, and strength of electric and magnetic field that are formed around this high-current channel of spark discharge and are powerful electromagnetic interference (PEMI) for objects of armaments and military equipment (OAME) were performed. It was shown that rise rates of HPC obtained for generator GINT-2 in the channel of long air spark discharge (of artificial lightning) and PEMI around this channel practically satisfy strict requirements of the NATO Standards AESTP-250: 2014 and USA MIL-STD-464C: 2010. Originality. The new scheme of design of CDC in composition of the modernized powerful ultra-high-voltage high-current generator of GINT-2 type (developer – Research and Design Institute «Molniya» of NTU «KhPI»), satisfying requirements of the mentioned standards for full-scale tests of OAME for EMC and immunity to action on them of PEMI from long atmospheric spark electric dis","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47331373","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}

{"title":"CONTROL CURRENT METHOD OF THE CONCENTRATION OF FERROMAGNETIC ELEMENTS IN THE WORKING CHAMBER OF THE TECHNOLOGICAL INDUCTOR OF MAGNETIC FIELD DURING ITS OPERATION","authors":"V. Milykh, L. Shilkova","doi":"10.20998/2074-272x.2020.5.02","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.5.02","url":null,"abstract":"Introduction. A rotating magnetic field three-phase inductor designed for the technological processing of various substances is considered. The processing is carried out by ferromagnetic elements in the form of pieces of iron wire moving with a magnetic field. Problem. The control problem of the concentration of ferromagnetic elements in the working chamber of the inductor is solved. This is necessary in order to replenish the chamber in time with elements that wear out but without interrupting the processing. Methodology. The proposed control method consists in observing the current of the inductor stator winding, which is carried out during its operation and does not require intervention in the technological process of processing. Results. The theoretical substantiation of the method is given and a practical calculation evaluation of its adequacy is made on the example of a specific inductor. The theory and practice of the method are based on numerical calculations of the magnetic field, electromagnetic parameters and the angular characteristics of the inductor. Practical value. The practical use of the method is to automatically determine the time of reloading the chamber with ferromagnetic elements that are worn out during the inductor operation. This increases the performance of the inductor and eliminates its downtime. References 10, figures 8.","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":"1 1","pages":"12-17"},"PeriodicalIF":0.8,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48576131","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}

{"title":"ANALYSIS OF THE STATE OF THE EXTERNAL LIGHTNING PROTECTION SYSTEM FOR OPERATING ENERGY OBJECTS","authors":"D. Koliushko, S. Rudenko, S. Kiprych","doi":"10.20998/2074-272x.2020.5.10","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.5.10","url":null,"abstract":"LPS of of 62305. LPS for these works. Goal. Development of an algorithm for evaluation of the current state LPS for existing power plants and substations. Methodology. Based on the analysis of IEC 62305, three stages of evaluation are proposed: (based on geodetic and electromagnetic method of the configuration of the object and of LPS), (based on the topographic survey method and the electromagnetic method for determining the configuration of the object and components of the LPS) and stage of analysis and development of recommendations. Results. Three stages, which are a basis of analysis of a condition of LPS based on the created algorithm, An example of the analysis LPS condition of the existing substation with a voltage of 35 kV, created according to the specified method, is given. The program report in 3D form illustrates the unprotected parts of the object. Originality. For the first an algorithm for analysis the state of LPS of operating energy facilities according to the IEC 62305 standard has been developed. Practical value. Typical remarks to the existing LPS are formed. The results of the work can be used","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42976990","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}

{"title":"SIMPLIFIED MATHEMATICAL MODEL OF GROUP OF OVERHEAD POWER LINES MAGNETIC FIELD","authors":"B. Kuznetsov, T. Nikitina, I. Bovdui","doi":"10.20998/2074-272x.2020.4.04","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.4.04","url":null,"abstract":"Aim. The method for design of simplified mathematical model of the group of overhead power lines magnetic field allowing to reduce the number of conductors which are taken into account in the model and field and allowing to reduce the sensitivity of the model to plant parameters uncertainty is developed. Methodology. The method based on the multi-criteria game decision, in which the payoff vector is calculated on the basis of the Maxwell equations quasi-stationary approximation solutions. The game decision based on the stochastic particles multiswarm optimization algorithms. The implementation of the method is carried out when determining the number, configuration, spatial arrangement and currents in conductors based on simplified mathematical model of the group of overhead power line magnetic field in a given space area . Results. Computer simulation and field experimental research results of simplified mathematical model on the example of the group of four overhead power lines magnetic field including 21 conductors where based on the developed simplified mathematical model of the magnetic field , the number of conductors taken into account in the model is reduced to 6, and the modeling error does not exceed 4 %. Originality. For the first time the method for design of simplified mathematical model of the group of overhead power lines magnetic field based on the stochastic particles multiswarm optimization algorithms, which allows to significantly simplify the simulation by reducing the number of conductors that are taken into account in the model and to reduce the sensitivity of the model to plant parameters uncertainty, and at the same time limit the modeling error at the engineering level to 5-10 %. Practical value. Practical recommendations on reasonable choice of the minimal number, configuration, spatial arrangement and currents in conductors for the simplified mathematical model of the group of overhead power line magnetic field. References figures 6.","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41464611","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}

{"title":"ANALYSIS OF CHARACTERISTICS AND POSSIBILITIES OF HIGH-VOLTAGE COMPLEX SCIENTIFIC-&-RESEARCH PLANNING-&-DESIGN INSTITUTE «MOLNIYA» OF NTU «KHPI» FOR THE TESTS OF OBJECTS OF ENERGY, ARMAMENT, AVIATION AND SPACE-ROCKET TECHNIQUE ON ELECTRIC SAFETY AND EMC","authors":"M. I. Baranov, S. Buriakovskyi, V. Kniaziev, S. Rudenko","doi":"10.20998/2074-272x.2020.4.06","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.4.06","url":null,"abstract":"","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":"1 1","pages":"37-53"},"PeriodicalIF":0.8,"publicationDate":"2020-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49538139","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}

{"title":"SIMULTANEOUS ALLOCATION OF MULTIPLE DISTRIBUTED GENERATION AND CAPACITORS IN RADIAL NETWORK USING GENETIC-SALP SWARM ALGORITHM","authors":"C. Djabali, T. Bouktir","doi":"10.20998/2074-272x.2020.4.08","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.4.08","url":null,"abstract":"Purpose. In recent years, the problem of allocation of distributed generation and capacitors banks has received special attention from many utilities and researchers. The present paper deals with single and simultaneous placement of dispersed generation and capacitors banks in radial distribution network with different load levels: light, medium and peak using genetic-salp swarm algorithm. The developed genetic-salp swarm algorithm (GA-SSA) hybrid optimization takes the system input variables of radial distribution network to find the optimal solutions to maximize the benefits of their installation with minimum cost to minimize the active and reactive power losses and improve the voltage profile. The validation of the proposed hybrid genetic-salp swarm algorithm was carried out on IEEE 34-bus test systems and real Algerian distributed network of Djanet (far south of Algeria) with 112-bus. The numerical results endorse the ability of the proposed algorithm to achieve a better results with higher accuracy compared to the result obtained by salp swarm algorithm, genetic algorithm, particle swarm optimization and the hybrid particle swarm optimization algorithms. References 27, tables 10, figures 12.","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":"1 1","pages":"59-66"},"PeriodicalIF":0.8,"publicationDate":"2020-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46297916","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}

{"title":"MATHEMATICAL MODELLING OF TRANSIENTS IN THE ELECTRIC DRIVE OF THE SWITCH – THE MAIN EXECUTIVE ELEMENT OF RAILWAY AUTOMATION","authors":"S. Buriakovskyi, A. Maslii, O. Pasko, V. Smirnov","doi":"10.20998/2074-272x.2020.4.03","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.4.03","url":null,"abstract":"Goal. To develop a mathematical and imitation model of the electric drive of the railroad switch as a twoand three-mass electromechanical system based on DC and AC motors as the main executive element of railway automation. The modelling is based on the parameters of the SP-6m switches as the main modification of the executive element of the Ukrainian domestic railways automation system. Methodology. The authors have presented the mechanical part of the railroad switch as a three-mass construction scheme with serial connection of elastic masses. Special attention is paid to the character of the movement of the switch point tongues, when describing them in the form of twoand threemass kinematic schemes, as well as to the mechanical state of the traction and connections as nodes, which are most sensitive to the negative effects of some modes of the railroad switch. Results. A simulation mathematical model of SP-6m switch for AC and DC motors, which allows to study the influence of various factors, has been developed and tested at the stand of the Automation Laboratory of the Ukrainian State University of Railway Transport, Kharkiv. The deviation in the basic parameters of the switch translation process is less than 5 %. Originality. For the first time a mathematical model of an electric drive of the railroad switch is developed, which takes into account elastic relations and load characteristics as an object of controlling the speed of movement of switch point tongues. Practical significance. We have created a mathematical model of the electric drive of the railroad switch which allows to examine the influence of various factors, including the influence of the environment on the operation of the switch. References 10, table 1, figures 10.","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":"1 1","pages":"17-23"},"PeriodicalIF":0.8,"publicationDate":"2020-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48774938","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}

{"title":"MODELLING OF OPERATION MODES AND ELECTROMAGNETIC INTERFERENCES OF GaN-TRANSISTOR CONVERTERS","authors":"Y. Onikienko, V. Pilinsky, P. Popovych, V. Lazebnyi, O. Smolenska, V. Baran","doi":"10.20998/2074-272x.2020.3.06","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.3.06","url":null,"abstract":"Goal. To analyze the efficiency and EMI of a half-bridge converter built on GaN transistors at different switching frequencies and to issue recommendations for its application. Methodology. An EPC9035 development board from Efficient Power Conversion was selected for research. This board is a half-bridge converter built on the EPC2022 eGaN® transistors and contains a driver for controlling these transistors. To simplify the assessment of the conversion efficiency, it is suggested to use a computer model of the development board and LISN, which simulates the active load with the LC filter. Results. Simulation results of the converter efficiency with the nominal values of the elements according to the EPC9035 manual showed significant deviations from the calculated values at frequencies above 50 kHz. This is explained by the presence of inrush current through transistors. The inrush current depends on the «dead time» between the intervals when the transistors are open and the delays specified in the SPICE model of LM5113 driver. To reduce the amplitude of inrush current and, accordingly, to increase the duration of the «dead time» interval, it is proposed to double the capacitors responsible for the formation of this interval. Simulation of the converter efficiency with the doubled values of the circuit elements showed that the results almost coincide with the calculated values of the efficiency in the range from 0.05 MHz to 5 MHz. The converter on the EPC2022 transistors has the highest efficiency at 50 kHz which decreases by 0.03-0.04 at 500 kHz. Therefore, it is recommended that the operating frequency should be set close to 500 kHz. Simulation of EMI levels resulted that the difference in the duration of the «dead time» does not have a significant effect on the levels of simulated EMI. The largest difference between the simulation results and the experiment is observed at frequencies about 30 MHz and is 3-6 dB. Originality. For the first time, the computer model was used to calculate the efficiency of a half-bridge converter on GaN transistors at different frequencies. Practical significance. Considering the high output current, high operating voltage and short switching times, GaN transistors are promising for use in pulse generators, power supplies with operating frequencies exceeding 500 kHz, and in powerful Class D hi-fi amplifiers with small dimensions, such as automotive ones. References 10, tables 3, figures 5.","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43510086","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}

{"title":"CALCULATION AND DESIGN OF A ROBUST SPEED CONTROLLER OF A FREQUENCY-CONTROLLED INDUCTION ELECTRIC DRIVE","authors":"N. J. Khlopenko","doi":"10.20998/2074-272x.2020.3.05","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.3.05","url":null,"abstract":"Purpose. The aim of the work is the calculation and design of a robust speed controller of a frequency-controlled induction electric drive with parametric uncertainty and the presence of interferences in the feedback channel. Methodology. The calculation and design of the controller was carried out in four stages. At the first stage, a linearized mathematical model of the control object with parametric uncertainty was constructed and the transfer function of the H∞-suboptimal controller was calculated in the Robust Control Toolbox using the mixed sensitivity method. At the second stage, the stability of the robust system and the accuracy of stabilization of the induction machine speed with random variations of the object's and controller's uncertain parameters within the specified boundaries were explored. At the third stage, the influence of interferences arising in the feedback channel on the speed of the electric motor was explored in the Simulink package. At the final stage, the transfer function of the H∞-suboptimal controller was decomposed into a continued fraction using the Euclidean algorithm. This fraction was used to build the electric scheme of the controller. Results. Computer modelling of the transfer function of H∞-suboptimal controller, the robust stabilization system for the speed of the frequency-controlled electric drive with random variations of the uncertain parameters of the object and the controller at specified boundaries, as well as with the presence of varying intensity interferences in the feedback channel, was carried out. The choice of variable parameters was carried out according to the Monte-Carlo method. The curves of transient processes of the induction machine speed with parametric uncertainty and at different ranges of interference are constructed, as well as a Bode diagram for an open system. By the scatter of the obtained curves of the transient processes, the accuracy of speed stabilization of the machine was determined, and according to the Bode diagram, stability reserves in the amplitude and the phase of the robust system were determined. They are within tolerances with comparatively large deviations of the varied parameters and the range of interferences. Based on the investigations, an electrical circuit of the H∞-suboptimal robust controller was developed. Originality. The mathematical model has been developed and the methodology for calculating and designing of H∞-suboptimal robust speed controller of the frequency-controlled system of an induction electric drive with random variations of the uncertain parameters of the object and the controller at determined boundaries and the presence of interferences in the feedback channel, ensuring the stability of the system with allowable reserves of the amplitude and the phase and high accuracy of speed stabilization of the machine within the tolerances of uncertain system parameters and interferences was proposed. Practical value. The obtained structure of the","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":"1 1","pages":"31-36"},"PeriodicalIF":0.8,"publicationDate":"2020-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46729101","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}

{"title":"MODELLING OF DYNAMIC MODES OF AN INDUCTION ELECTRIC DRIVE AT PERIODIC LOAD","authors":"V. Malyar, O. Hamola, V. Maday","doi":"10.20998/2074-272x.2020.3.02","DOIUrl":"https://doi.org/10.20998/2074-272x.2020.3.02","url":null,"abstract":"Goal: Development of methods and mathematical models, based on them, for the calculation of transients and steady-state modes of induction electric drives operating in periodic load mode. \u0000 \u0000Methodology: The developed algorithms are based on a mathematical model of an induction motor, which takes into account the saturation of the magnetic core and the displacement of current in the rotor bars. The processes are described by a system of nonlinear differential equations in the orthogonal axes x, y, which enables the results to be obtained with the smallest amount of calculations. The magnetization characteristics by the main magnetic flux and the leakage fluxes are used to calculate the electromagnetic parameters of the motor. To account for the current displacement in the rotor bars, the short-circuited winding is considered as a multilayer structure formed by dividing the bars in height by several elements. \u0000 \u0000Results: Due to the variable load on the motor shaft, electromagnetic processes in both transient and steady state modes of the electric drive in any coordinate system are described by a system of nonlinear differential equations. The result of the calculation of the transients is obtained as a result of their integration time dependencies of coordinates (currents, electromagnetic torque, etc.) at a given law of change of the moment of loading. The proposed method of calculating steady-state mode is based on algebraization of differential equations on the mesh of nodes of the process cyclicity period and allows to obtain periodic dependencies in the time domain. \u0000 \u0000Originality: The problem of calculating a steady-state periodic mode is solved as a boundary problem for a system of first-order differential equations with periodic boundary conditions, which allows to obtain instantaneous dependences during the period of currents, electromagnetic torque, capacities and other coordinates. \u0000 \u0000Practical significance: Using the developed algorithm, it is possible to calculate the static characteristics of periodic processes as dependencies on different parameters of the cycle of periodic load or other coordinates, which is the basis for the choice of the motor for overload, power, heating, etc., as well as to detect the possibility of resonance.","PeriodicalId":44198,"journal":{"name":"Electrical Engineering & Electromechanics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47190889","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}