Pub Date : 2001-06-25DOI: 10.1109/ICSD.2001.955647
K. Temmen, A. Khaddour, D. Peier
Hydrophobicity and the ability to recover hydrophobicity after loss are the base of an outstanding operation behaviour of silicone as insulating material. The imperfect understanding of the fundamentals of hydrophobicity loss and recovery stems from the difficulty of separating the various direct and indirect mechanisms. Measurements of the static contact angle of surfaces stressed with vertical electric field prove the influence of the electric field on hydrophobicity loss. On the other hand no significant influence on hydrophobicity can be observed after ageing the surface using electric field stress parallel to the silicone surface. These results will form the basis for a physically based model for interpretation of hydrophobicity loss and recovery. The results provide the opportunity for systematic investigations concerning hydrophobicity loss and recovery comparison of different surfaces, because of the high reproducibility of the electric field compared to the more stochastic behaviour of partial discharges. With this knowledge suitable testing methods can be developed to evaluate long term hydrophobicity behaviour.
{"title":"Quantitative analysis of hydrophobicity loss due to electric field strength","authors":"K. Temmen, A. Khaddour, D. Peier","doi":"10.1109/ICSD.2001.955647","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955647","url":null,"abstract":"Hydrophobicity and the ability to recover hydrophobicity after loss are the base of an outstanding operation behaviour of silicone as insulating material. The imperfect understanding of the fundamentals of hydrophobicity loss and recovery stems from the difficulty of separating the various direct and indirect mechanisms. Measurements of the static contact angle of surfaces stressed with vertical electric field prove the influence of the electric field on hydrophobicity loss. On the other hand no significant influence on hydrophobicity can be observed after ageing the surface using electric field stress parallel to the silicone surface. These results will form the basis for a physically based model for interpretation of hydrophobicity loss and recovery. The results provide the opportunity for systematic investigations concerning hydrophobicity loss and recovery comparison of different surfaces, because of the high reproducibility of the electric field compared to the more stochastic behaviour of partial discharges. With this knowledge suitable testing methods can be developed to evaluate long term hydrophobicity behaviour.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125032444","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955703
A. Pemen, P.C.T. van der Laan, W. de Leeuw
Partial discharge (PD) measurements are an effective tool to assess the condition of important power plant components, such as the generator, the generator circuit-breaker and the step-up transformer.This paper shows that, in addition to phase-resolved patterns, the waveshapes of PD signals provide valuable information on the type and origin of the discharges. The authors describe the complex propagation of PD signals in a stator winding and the consequences for PD detection. Results from on-line measurements in three power plants where abnormal PD activity was observed are presented. In all cases the source of the PD's ccan be located: (i) slot discharges in a 125 MW generator, (ii) interphase discharges in the end-windings of a 165 MW generator, and (iii) an improperly installed bleeding resistor in a generator-circuit breaker.
{"title":"Analysis and localization of spurious partial discharge activity in generator units","authors":"A. Pemen, P.C.T. van der Laan, W. de Leeuw","doi":"10.1109/ICSD.2001.955703","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955703","url":null,"abstract":"Partial discharge (PD) measurements are an effective tool to assess the condition of important power plant components, such as the generator, the generator circuit-breaker and the step-up transformer.This paper shows that, in addition to phase-resolved patterns, the waveshapes of PD signals provide valuable information on the type and origin of the discharges. The authors describe the complex propagation of PD signals in a stator winding and the consequences for PD detection. Results from on-line measurements in three power plants where abnormal PD activity was observed are presented. In all cases the source of the PD's ccan be located: (i) slot discharges in a 125 MW generator, (ii) interphase discharges in the end-windings of a 165 MW generator, and (iii) an improperly installed bleeding resistor in a generator-circuit breaker.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116127773","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955656
M. Ravier, F. Carmona, F. Houzé, U. Nilsson, A. Campus
We have reported the first use of the Resiscope associated to an atomic force microscope (AFM) for investigating composite materials comprising an insulating matrix and conducting particles. For the first time we have been able to visualise the "conducting paths" through the materials which have long been supposed to exist in such heterogeneous materials. A systematic characterisation of their three dimensional electrical mesostructure including the sample thickness as an independent variable is now possible with this new instrument.
{"title":"A new tool for investigating the electrical structure of carbon black filled polymers","authors":"M. Ravier, F. Carmona, F. Houzé, U. Nilsson, A. Campus","doi":"10.1109/ICSD.2001.955656","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955656","url":null,"abstract":"We have reported the first use of the Resiscope associated to an atomic force microscope (AFM) for investigating composite materials comprising an insulating matrix and conducting particles. For the first time we have been able to visualise the \"conducting paths\" through the materials which have long been supposed to exist in such heterogeneous materials. A systematic characterisation of their three dimensional electrical mesostructure including the sample thickness as an independent variable is now possible with this new instrument.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"211 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116405823","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955603
A. See, L. Dissado, J. Fothergill
The advent of experimental techniques capable of directly measuring the density of space charge in insulators under voltage in a non-destructive manner has revealed the existence of charge packet formation at high DC fields. In these circumstances space charge is observed to cross the insulation in the form of a packet rather than through the steady advance of a charge front. Such packets have been observed both in cable insulation, and in thin films. Since they occur at high fields before an electric failure occurs they are of interest as a possible pre-breakdown phenomenon. For this reason there is an interest in understanding the phenomena. In the experiments reported here we explore the electrical conditions required for the initiation of very slow moving charge packets in XLPE.
{"title":"Electric field requirements for charge packet generation and movement in XLPE","authors":"A. See, L. Dissado, J. Fothergill","doi":"10.1109/ICSD.2001.955603","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955603","url":null,"abstract":"The advent of experimental techniques capable of directly measuring the density of space charge in insulators under voltage in a non-destructive manner has revealed the existence of charge packet formation at high DC fields. In these circumstances space charge is observed to cross the insulation in the form of a packet rather than through the steady advance of a charge front. Such packets have been observed both in cable insulation, and in thin films. Since they occur at high fields before an electric failure occurs they are of interest as a possible pre-breakdown phenomenon. For this reason there is an interest in understanding the phenomena. In the experiments reported here we explore the electrical conditions required for the initiation of very slow moving charge packets in XLPE.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128606714","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955518
G. Montanari, Giovanni Mazzanti, F. Palmieri, G. Perego, S. Serra
This paper shows that the charge detrapping rate follows an Arrhenius-type law when the poling electrical field is large enough to cause copious injection of electrons, so that the transport and trapping process is dominated by electronic carriers. At fields close to the charge accumulation threshold, the tested materials, LDPE and XLPE, suggest that the conduction mechanism takes into account both ionic and electronic charge carriers. The threshold field for space charge accumulation significantly decreases as the temperature increases, at least in the range 20 to 60 /spl deg/C, even if it seems that the temperature dependence becomes smoother above 50 to 60 /spl deg/C. The increase of mobility with temperature and, thus, of charge depletion rate, after each polarisation voltage reversal, also follows an Arrhenius-type law, with smaller activation energy values for XLPE. These results must be considered when designing dc polymeric insulation systems, such as HVDC cables, since charge accumulation is a degradation acceleration factor and the temperature distribution in the cable can change significantly with loading conditions.
{"title":"Dependence of space-charge trapping threshold on temperature in polymeric DC cables","authors":"G. Montanari, Giovanni Mazzanti, F. Palmieri, G. Perego, S. Serra","doi":"10.1109/ICSD.2001.955518","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955518","url":null,"abstract":"This paper shows that the charge detrapping rate follows an Arrhenius-type law when the poling electrical field is large enough to cause copious injection of electrons, so that the transport and trapping process is dominated by electronic carriers. At fields close to the charge accumulation threshold, the tested materials, LDPE and XLPE, suggest that the conduction mechanism takes into account both ionic and electronic charge carriers. The threshold field for space charge accumulation significantly decreases as the temperature increases, at least in the range 20 to 60 /spl deg/C, even if it seems that the temperature dependence becomes smoother above 50 to 60 /spl deg/C. The increase of mobility with temperature and, thus, of charge depletion rate, after each polarisation voltage reversal, also follows an Arrhenius-type law, with smaller activation energy values for XLPE. These results must be considered when designing dc polymeric insulation systems, such as HVDC cables, since charge accumulation is a degradation acceleration factor and the temperature distribution in the cable can change significantly with loading conditions.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129485798","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955701
H.N. Nagamani, S.N. Moorching, Channakeshava, T. Basavaraju
Central Power Reseach Institute (CPRI) has necessary facilities for on-line partial discharge measurement on Capacitor banks. Measurement of switching transients, harmonics and other system disturbances appearing on the capacitor banks can also be undertaken. Such investigation will be of great help in (a) diagnosing the condition of the capacitors in operation, (b) deciding the type of circuit breakers ta be used for capacitor switching operation and also (c) to assess the performance of capacitor banks under switching transients. The proposed acoustic emission technique can be employed as a diagnostic tool for on-line condition monitoring of power capacitors as the technique is non destructive, the instrument is compact, portable and easy to operate at site as capacitors need not be disconnected from the capacitor bank.
{"title":"On-line diagnostic technique for monitoring partial discharges in capacitor banks","authors":"H.N. Nagamani, S.N. Moorching, Channakeshava, T. Basavaraju","doi":"10.1109/ICSD.2001.955701","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955701","url":null,"abstract":"Central Power Reseach Institute (CPRI) has necessary facilities for on-line partial discharge measurement on Capacitor banks. Measurement of switching transients, harmonics and other system disturbances appearing on the capacitor banks can also be undertaken. Such investigation will be of great help in (a) diagnosing the condition of the capacitors in operation, (b) deciding the type of circuit breakers ta be used for capacitor switching operation and also (c) to assess the performance of capacitor banks under switching transients. The proposed acoustic emission technique can be employed as a diagnostic tool for on-line condition monitoring of power capacitors as the technique is non destructive, the instrument is compact, portable and easy to operate at site as capacitors need not be disconnected from the capacitor bank.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114071591","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955508
J. Wojkiewicz, S. Fauveaux, J. Miane
Intrinsically conducting polymers (ICP's) and their blends with thermoplastics are very promising for applications in electromagnetic interference shielding (EMI). They can have relatively high conductivities and permittivities and these properties can be tuned easily from insulating to conducting states through chemical processes. Compared to metals, ICP's are light, flexible and they can not only reflect but also absorb electromagnetic radiations. We report results obtained from polyaniline blends with thermoplastics in terms of variation of conductivity, permittivity and shielding effectiveness in function of the process of transformation of polymers, the mass fraction of polyaniline in the blends and the frequency in microwave and millimeter bands. The possibility to have low percolation threshold is very attractive to make materials with mechanical properties of the thermoplastics with the electronic properties of the ICP's. The high value of shielding coefficient shows that ICP's are efficient materials for such applications.
{"title":"Dielectric behavior and shielding properties of polyaniline composites","authors":"J. Wojkiewicz, S. Fauveaux, J. Miane","doi":"10.1109/ICSD.2001.955508","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955508","url":null,"abstract":"Intrinsically conducting polymers (ICP's) and their blends with thermoplastics are very promising for applications in electromagnetic interference shielding (EMI). They can have relatively high conductivities and permittivities and these properties can be tuned easily from insulating to conducting states through chemical processes. Compared to metals, ICP's are light, flexible and they can not only reflect but also absorb electromagnetic radiations. We report results obtained from polyaniline blends with thermoplastics in terms of variation of conductivity, permittivity and shielding effectiveness in function of the process of transformation of polymers, the mass fraction of polyaniline in the blends and the frequency in microwave and millimeter bands. The possibility to have low percolation threshold is very attractive to make materials with mechanical properties of the thermoplastics with the electronic properties of the ICP's. The high value of shielding coefficient shows that ICP's are efficient materials for such applications.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"74 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114110851","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955583
S. Fujita, Y. Kamei, K. Tanaka
This study examined the effect of water absorption by measuring the thermal properties and conduction current of a polyimide film that was soaked in distilled water. The effect of water absorption on the formation of space charge was also studied by evaluating the space charge density and its distribution as a function of time after bias voltage was applied to the sample.
{"title":"Effect of water absorption in polyimide on electrical properties","authors":"S. Fujita, Y. Kamei, K. Tanaka","doi":"10.1109/ICSD.2001.955583","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955583","url":null,"abstract":"This study examined the effect of water absorption by measuring the thermal properties and conduction current of a polyimide film that was soaked in distilled water. The effect of water absorption on the formation of space charge was also studied by evaluating the space charge density and its distribution as a function of time after bias voltage was applied to the sample.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129992648","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955634
S. Maeta, Y. Kamitani, T. Nukuto, M. Takata, M. Yoshiura
In order to make the electronic transport mechanism in organic substances clear in detail, the thermally stimulated current (TSC) method is very effective. From the TSC method, three parameters such as an energy depth E/sub t/ [eV] of the carrier trap site, a preexponential parameter (or an escape frequency factor) /spl nu/ [s/sup -1/] and a charge carrier density n/sub t/ [m/sup -3/] relating to the phenomena, can be estimated. We have completed some theories that enable us to analyze in detail TSC data obtained experimentally. One of them, the asymptotic estimation method (AEM) originally proposed by us, enables us to evaluate these three parameters accurately. And this has been expanded extensively to estimate 3N parameters, through an exact auto-separation (AS) method of various composite TSC curves and through the reconstruction (RC) method of TSC curves with no peak obtained by partially repeated heating cooling procedures. Where N is the number of the single TSC curve of the first-order included in the objects. The fine advantages are that these expanded theories have higher accuracy than 4 significant figures. Then, detail analyses of discrete states became possible by using both methods.
{"title":"Behavior of the discrete states observed through detailed analyses of TSC curves","authors":"S. Maeta, Y. Kamitani, T. Nukuto, M. Takata, M. Yoshiura","doi":"10.1109/ICSD.2001.955634","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955634","url":null,"abstract":"In order to make the electronic transport mechanism in organic substances clear in detail, the thermally stimulated current (TSC) method is very effective. From the TSC method, three parameters such as an energy depth E/sub t/ [eV] of the carrier trap site, a preexponential parameter (or an escape frequency factor) /spl nu/ [s/sup -1/] and a charge carrier density n/sub t/ [m/sup -3/] relating to the phenomena, can be estimated. We have completed some theories that enable us to analyze in detail TSC data obtained experimentally. One of them, the asymptotic estimation method (AEM) originally proposed by us, enables us to evaluate these three parameters accurately. And this has been expanded extensively to estimate 3N parameters, through an exact auto-separation (AS) method of various composite TSC curves and through the reconstruction (RC) method of TSC curves with no peak obtained by partially repeated heating cooling procedures. Where N is the number of the single TSC curve of the first-order included in the objects. The fine advantages are that these expanded theories have higher accuracy than 4 significant figures. Then, detail analyses of discrete states became possible by using both methods.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"261 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115208281","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 : 2001-06-25DOI: 10.1109/ICSD.2001.955593
T. Lebey, D. Malec, E. Dutarde
500/spl mu/m thickness CVD diamond samples of different grades related to the sp2/sp3 phase ratio and able to be used as substrates in power electronic applications have been characterized. The following conclusions may be drawn: breakdown and resistivity values of thick CVD diamond are far from the ones claimed for thin film (/spl sim/MV/cm). and for the natural materials (/spl sim/10 MV/cm) Samples presenting the largest amount of nitrogen behave from an electrical point of view better than pure "undoped" diamond samples.
{"title":"Breakdown characteristics of different grades of CVD diamond samples","authors":"T. Lebey, D. Malec, E. Dutarde","doi":"10.1109/ICSD.2001.955593","DOIUrl":"https://doi.org/10.1109/ICSD.2001.955593","url":null,"abstract":"500/spl mu/m thickness CVD diamond samples of different grades related to the sp2/sp3 phase ratio and able to be used as substrates in power electronic applications have been characterized. The following conclusions may be drawn: breakdown and resistivity values of thick CVD diamond are far from the ones claimed for thin film (/spl sim/MV/cm). and for the natural materials (/spl sim/10 MV/cm) Samples presenting the largest amount of nitrogen behave from an electrical point of view better than pure \"undoped\" diamond samples.","PeriodicalId":239585,"journal":{"name":"ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117)","volume":"190 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114848715","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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