Pub Date : 2016-09-01DOI: 10.1109/DEIV.2016.7763992
M. Weuffel, D. Gentsch, G. Nikolić, A. Schnettler
Depending on the operating current and the ambient conditions, the operating temperature of vacuum interrupters (VIs) may vary. An increase in VI temperature can result from heat loss at electrical contact resistance points, whereas a significant decrease in temperature will especially occur if VIs are used in future applications in a liquid nitrogen (LN2) environment (e.g. in combination with high-temperature superconducting equipment). In both cases of increased and decreased VI temperature, the pressure inside the VI may vary due to the adsorption and desorption of bound residual gases and changing material properties. This paper addresses the influence of VI temperature on internal pressure and on the applicability of the magnetron method for the measurement of internal pressure. By means of experimental test series that varied the internal pressure in punctured (i.e. non-vented) VIs and the ambient temperature, we found that an increase in VI temperature leads to a limited increase in internal pressure due to desorption of bound residual gases. Correspondingly, immersing the VI into LN2 causes a significant adsorption of residual gases, resulting in a pressure decrease of up to several orders of magnitude. In both cases the magnetron method is generally applicable, although ignition behavior is considerably affected by adsorption in an LN2 environment.
{"title":"The influence of temperature on internal pressure in vacuum interrupters in a liquid nitrogen environment","authors":"M. Weuffel, D. Gentsch, G. Nikolić, A. Schnettler","doi":"10.1109/DEIV.2016.7763992","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7763992","url":null,"abstract":"Depending on the operating current and the ambient conditions, the operating temperature of vacuum interrupters (VIs) may vary. An increase in VI temperature can result from heat loss at electrical contact resistance points, whereas a significant decrease in temperature will especially occur if VIs are used in future applications in a liquid nitrogen (LN2) environment (e.g. in combination with high-temperature superconducting equipment). In both cases of increased and decreased VI temperature, the pressure inside the VI may vary due to the adsorption and desorption of bound residual gases and changing material properties. This paper addresses the influence of VI temperature on internal pressure and on the applicability of the magnetron method for the measurement of internal pressure. By means of experimental test series that varied the internal pressure in punctured (i.e. non-vented) VIs and the ambient temperature, we found that an increase in VI temperature leads to a limited increase in internal pressure due to desorption of bound residual gases. Correspondingly, immersing the VI into LN2 causes a significant adsorption of residual gases, resulting in a pressure decrease of up to several orders of magnitude. In both cases the magnetron method is generally applicable, although ignition behavior is considerably affected by adsorption in an LN2 environment.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115743736","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7764001
Byoung-Chul Kim, Sung-tae Kim, K. Ahn, Young-geun Kim
Back-to-back capacitive bank switching is the most severe duty among capacitive current switching duties because the amplitude of the inrush current with high frequency is very large. In this paper, 36kV back-to-back capacitive current switching tests of test duty 2(BC2) were carried out with vacuum circuit breaker. And the tests were performed with a series of separate making tests of 120 operations followed by a series of CO tests of 120 operations due to limitations of the test plant according to IEC standards 62271-100. The two types of VCB were tested with single phase and the test results were compared in terms of pre-arcing time, break down voltage distribution, contact surface after tests, contacting area, and field enhancement factor.
{"title":"Study on back to back capacitive current switching of 36kV vacuum circuit breaker","authors":"Byoung-Chul Kim, Sung-tae Kim, K. Ahn, Young-geun Kim","doi":"10.1109/DEIV.2016.7764001","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7764001","url":null,"abstract":"Back-to-back capacitive bank switching is the most severe duty among capacitive current switching duties because the amplitude of the inrush current with high frequency is very large. In this paper, 36kV back-to-back capacitive current switching tests of test duty 2(BC2) were carried out with vacuum circuit breaker. And the tests were performed with a series of separate making tests of 120 operations followed by a series of CO tests of 120 operations due to limitations of the test plant according to IEC standards 62271-100. The two types of VCB were tested with single phase and the test results were compared in terms of pre-arcing time, break down voltage distribution, contact surface after tests, contacting area, and field enhancement factor.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123114773","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7764027
V. Burdovitsin, A. Kazakov, A. Medovnik, E. Oks
The paper describes results of development and investigation processes of pulsed electron beam generation by a plasma electron source in the fore-vacuum pressure range (3-20 Pa). The plasma electron source is based on the cathodic arc discharge. The quasi-stationary pulse length range for electron beam generation is attractive due to possibility of single pulse electron beam technology. One of the main advantages for the fore-vacuum plasma electron sources is its ability for direct treatment dielectric substrates, like ceramics and polymers. Characteristics of the quasi-stationary (1.8 ms) electron beam source based on the arc discharge and research of an electron beam formation in the fore-vacuum pressure range are presented and discussed.
{"title":"Generation of quasi-stationary broad pulsed electron beam by the forevacuum plasma source based on the arc discharge","authors":"V. Burdovitsin, A. Kazakov, A. Medovnik, E. Oks","doi":"10.1109/DEIV.2016.7764027","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7764027","url":null,"abstract":"The paper describes results of development and investigation processes of pulsed electron beam generation by a plasma electron source in the fore-vacuum pressure range (3-20 Pa). The plasma electron source is based on the cathodic arc discharge. The quasi-stationary pulse length range for electron beam generation is attractive due to possibility of single pulse electron beam technology. One of the main advantages for the fore-vacuum plasma electron sources is its ability for direct treatment dielectric substrates, like ceramics and polymers. Characteristics of the quasi-stationary (1.8 ms) electron beam source based on the arc discharge and research of an electron beam formation in the fore-vacuum pressure range are presented and discussed.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123275584","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7764021
A. Kaziev, D. Kolodko, A. Tumarkin, M. Kharkov, T. V. Stepanova
A pulsed non-sputtering magnetron discharge (NSMD) has been studied by Langmuir probe diagnostics and a retarding field energy analyzer (RFA) mounted inside the cathode. Both axial and radial profiles of plasma density and electron temperature are nearly uniform in the magnetic null region. The plasma potential measurements have yielded a positive anode sheath voltage drop Uas ~ 0.4Ud and a corresponding cathode sheath drop Ucs ~ 0.6Ud. RFA results demonstrate that the energy of ions incident at the cathode surface during NSMD does not exceed eUcs. This result is in accordance with the observed inhibition of sputtering process in the NSMD.
{"title":"Ion energy distributions at a cathode in a non-sputtering magnetron discharge","authors":"A. Kaziev, D. Kolodko, A. Tumarkin, M. Kharkov, T. V. Stepanova","doi":"10.1109/DEIV.2016.7764021","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7764021","url":null,"abstract":"A pulsed non-sputtering magnetron discharge (NSMD) has been studied by Langmuir probe diagnostics and a retarding field energy analyzer (RFA) mounted inside the cathode. Both axial and radial profiles of plasma density and electron temperature are nearly uniform in the magnetic null region. The plasma potential measurements have yielded a positive anode sheath voltage drop Uas ~ 0.4Ud and a corresponding cathode sheath drop Ucs ~ 0.6Ud. RFA results demonstrate that the energy of ions incident at the cathode surface during NSMD does not exceed eUcs. This result is in accordance with the observed inhibition of sputtering process in the NSMD.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121878657","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748706
Koki Kojima, Ryoji Oshiro, E. Kaneko
It is well known that vacuum circuit breakers (VCB) have such superior characteristics as small size, light weight, small noise, frequent interruption, easy maintenance, and no decomposition products emission. On the other hand, some kind of surge generation may be their only one drawback. Just after the small current interruption with a very short arcing time, a repetitive re-ignition or three phase simultaneous interruption sometimes occurs. Surges related to these phenomena are considered the serious causes of insulation damage of the equipment in distribution power systems. In order to clarify these surge generation mechanisms, we did the experiment on the high frequency (HF) current interruption and the recovery characteristics of VCB with very short arcing time. We investigated the effect of a high frequency current on the dielectric recovery characteristics after the high frequency current interruption by means of synthetic test circuit in short electrode gap. For experiment parameters, we changed HF current frequency, amplitude of HF current values (about 350A and 750A) and impulse voltage (less than 8kV), arcing time(several hundred micro seconds) and delay time of impulse voltage application after HF current interrupted(several micro seconds). In this paper, the result of experiment will be reported.
{"title":"Study on high frequency current interruption characteristics of vacuum circuit breaker","authors":"Koki Kojima, Ryoji Oshiro, E. Kaneko","doi":"10.1109/DEIV.2016.7748706","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748706","url":null,"abstract":"It is well known that vacuum circuit breakers (VCB) have such superior characteristics as small size, light weight, small noise, frequent interruption, easy maintenance, and no decomposition products emission. On the other hand, some kind of surge generation may be their only one drawback. Just after the small current interruption with a very short arcing time, a repetitive re-ignition or three phase simultaneous interruption sometimes occurs. Surges related to these phenomena are considered the serious causes of insulation damage of the equipment in distribution power systems. In order to clarify these surge generation mechanisms, we did the experiment on the high frequency (HF) current interruption and the recovery characteristics of VCB with very short arcing time. We investigated the effect of a high frequency current on the dielectric recovery characteristics after the high frequency current interruption by means of synthetic test circuit in short electrode gap. For experiment parameters, we changed HF current frequency, amplitude of HF current values (about 350A and 750A) and impulse voltage (less than 8kV), arcing time(several hundred micro seconds) and delay time of impulse voltage application after HF current interrupted(several micro seconds). In this paper, the result of experiment will be reported.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123967969","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7763986
Fan Zhang, Yang Lv, X. Duan, M. Liao, J. Zou
Based on a special angle of voltage or current of power system, controlled switching technology of vacuum circuit breaker is presented to decrease overvoltage and inrush current due to the power equipment operating such as transmission line closing and no-load transformer closing. The optimum switching instant and synchronous switching control strategies are given by synthetically considering closing action time dispersion and pre-strike characteristic of vacuum circuit breaker. The optimal target points of the controlled switching technology are deduced and calculated by Matlab. The switching over voltages are simulated by statistical in ATPdraw. Simulation results show that the closing voltage of transmission can be reduced to 2.35 p.u. and switching voltage of transformer can be reduced to 1.85 p.u. So the theoretical analysis and synchronous switching control strategies in the article are verified correctly.
{"title":"Investigation on phasing controlled vacuum circuit breaker for switching overvoltage of 110kV power system","authors":"Fan Zhang, Yang Lv, X. Duan, M. Liao, J. Zou","doi":"10.1109/DEIV.2016.7763986","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7763986","url":null,"abstract":"Based on a special angle of voltage or current of power system, controlled switching technology of vacuum circuit breaker is presented to decrease overvoltage and inrush current due to the power equipment operating such as transmission line closing and no-load transformer closing. The optimum switching instant and synchronous switching control strategies are given by synthetically considering closing action time dispersion and pre-strike characteristic of vacuum circuit breaker. The optimal target points of the controlled switching technology are deduced and calculated by Matlab. The switching over voltages are simulated by statistical in ATPdraw. Simulation results show that the closing voltage of transmission can be reduced to 2.35 p.u. and switching voltage of transformer can be reduced to 1.85 p.u. So the theoretical analysis and synchronous switching control strategies in the article are verified correctly.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123971226","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748662
H. Kojima, T. Takahashi, M. Noda, K. Hasegawa, M. Sakaki, N. Hayakawa
Spark conditioning is one of the effective measures to improve the dielectric strength in vacuum. In this paper, we obtained the breakdown (BD) charge dependence for spark conditioning in vacuum under various non-uniform electric field and anode materials, and discussed the BD mechanism in terms of BD based on anode heating or cathode heating. Experimental results revealed that, in the case of BD based on anode heating, the longer the gap distance was, the larger the BD charge to obtain maximum dielectric strength was. On the other hand, in the case of BD based on cathode heating, the BD charge for maximum dielectric strength was smaller than that in the case of BD based on anode heating. From these results, we can estimate the optimal BD charge for the spark conditioning in vacuum.
{"title":"Optimum breakdown charge for spark conditioning in vacuum under non-uniform electric field","authors":"H. Kojima, T. Takahashi, M. Noda, K. Hasegawa, M. Sakaki, N. Hayakawa","doi":"10.1109/DEIV.2016.7748662","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748662","url":null,"abstract":"Spark conditioning is one of the effective measures to improve the dielectric strength in vacuum. In this paper, we obtained the breakdown (BD) charge dependence for spark conditioning in vacuum under various non-uniform electric field and anode materials, and discussed the BD mechanism in terms of BD based on anode heating or cathode heating. Experimental results revealed that, in the case of BD based on anode heating, the longer the gap distance was, the larger the BD charge to obtain maximum dielectric strength was. On the other hand, in the case of BD based on cathode heating, the BD charge for maximum dielectric strength was smaller than that in the case of BD based on anode heating. From these results, we can estimate the optimal BD charge for the spark conditioning in vacuum.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125334626","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748747
S. V. Klochko, A. A. Logachev, I. N. Poluyanova
We investigated the development of high-current vacuum arc on the axial magnetic field contacts. The arc was initiated by opening of the contacts. We considered the processes during half wave of the industrial frequency current in the range of current from 0.1 to 1.2 of breaking capacity of the contact system. Using the high-speed video we investigated the time dependence of the plasma luminosity in the gap between the electrodes and the shape of luminous column. It has been shown, that high-current electrodes material evaporation has a notable effect on processes in the gap between the electrodes, but it doesn't cause contraction.
{"title":"Investigation of the dynamics of high-current vacuum arc luminosity","authors":"S. V. Klochko, A. A. Logachev, I. N. Poluyanova","doi":"10.1109/DEIV.2016.7748747","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748747","url":null,"abstract":"We investigated the development of high-current vacuum arc on the axial magnetic field contacts. The arc was initiated by opening of the contacts. We considered the processes during half wave of the industrial frequency current in the range of current from 0.1 to 1.2 of breaking capacity of the contact system. Using the high-speed video we investigated the time dependence of the plasma luminosity in the gap between the electrodes and the shape of luminous column. It has been shown, that high-current electrodes material evaporation has a notable effect on processes in the gap between the electrodes, but it doesn't cause contraction.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129771673","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748732
M. D. Cunha, M. Benilov, Werner Hartmann, N. Wenzel
Instability stemming from the strong dependence of electron emission current on the local surface temperature plays an important role in current transfer to hot cathodes of arc discharges. In the case of vacuum arcs, this instability may lead to micro explosions on cathode surface even if the surface is planar. This work is concerned with numerical simulation of effect produced by surface non-uniformities. It is found that the effect is non-trivial: the presence of surface non-uniformities can not only accelerate the development of the instability, which is what one would expect intuitively, but also slow it down and even suppress.
{"title":"Simulation of thermal instability in non-uniformities on the surface of cathodes of vacuum arcs","authors":"M. D. Cunha, M. Benilov, Werner Hartmann, N. Wenzel","doi":"10.1109/DEIV.2016.7748732","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748732","url":null,"abstract":"Instability stemming from the strong dependence of electron emission current on the local surface temperature plays an important role in current transfer to hot cathodes of arc discharges. In the case of vacuum arcs, this instability may lead to micro explosions on cathode surface even if the surface is planar. This work is concerned with numerical simulation of effect produced by surface non-uniformities. It is found that the effect is non-trivial: the presence of surface non-uniformities can not only accelerate the development of the instability, which is what one would expect intuitively, but also slow it down and even suppress.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"373 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124668240","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 : 2016-09-01DOI: 10.1109/DEIV.2016.7748669
E. Nefedtsev, A. Batrakov
The paper reports on a numerical simulation of stable stage of plasma flare expansion from an explosive emission center. The calculations were made on the base of the three-fluid hydrodynamic model corrected to provide a consistent description of both electron and ion transfer in plasma and electron transfer in a vacuum gap between plasma and an anode. Concentration, flow velocity, and temperature of plasma flare components are analyzed.
{"title":"Plasma expansion in vacuum gap: Three-fluid hydrodynamic simulation","authors":"E. Nefedtsev, A. Batrakov","doi":"10.1109/DEIV.2016.7748669","DOIUrl":"https://doi.org/10.1109/DEIV.2016.7748669","url":null,"abstract":"The paper reports on a numerical simulation of stable stage of plasma flare expansion from an explosive emission center. The calculations were made on the base of the three-fluid hydrodynamic model corrected to provide a consistent description of both electron and ion transfer in plasma and electron transfer in a vacuum gap between plasma and an anode. Concentration, flow velocity, and temperature of plasma flare components are analyzed.","PeriodicalId":296641,"journal":{"name":"2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124045220","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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