Pub Date : 2004-09-27DOI: 10.1109/TDEI.2006.1593404
C.R. Li, L. Ding, J.Z. Lu
Alumina ceramic samples prepared under different sintering temperatures and varied additives were measured to indicate the trap density and trap energy located in alumina materials by using thermally stimulated current (TSC). The surface charges on alumina in vacuum after applying a negative pulse voltage (0.7/4 /spl mu/s), and flashover performances of the materials in vacuum also were measured. We found that the trap distribution in alumina has a correlation with surface charges and flashover performances in vacuum. It is shown that the higher is the trap density in the material, the higher is the surface charge density, and the lower is the flashover voltage on alumina surface. It is believed that the trapping and de-trapping mechanisms of carriers could play an important role during the development of the discharge processes, together with the secondary electron emission mechanism.
{"title":"The relation of trap distribution of alumina with surface flashover performance in vacuum","authors":"C.R. Li, L. Ding, J.Z. Lu","doi":"10.1109/TDEI.2006.1593404","DOIUrl":"https://doi.org/10.1109/TDEI.2006.1593404","url":null,"abstract":"Alumina ceramic samples prepared under different sintering temperatures and varied additives were measured to indicate the trap density and trap energy located in alumina materials by using thermally stimulated current (TSC). The surface charges on alumina in vacuum after applying a negative pulse voltage (0.7/4 /spl mu/s), and flashover performances of the materials in vacuum also were measured. We found that the trap distribution in alumina has a correlation with surface charges and flashover performances in vacuum. It is shown that the higher is the trap density in the material, the higher is the surface charge density, and the lower is the flashover voltage on alumina surface. It is believed that the trapping and de-trapping mechanisms of carriers could play an important role during the development of the discharge processes, together with the secondary electron emission mechanism.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126942851","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418645
Z. Shi, S. Jia, Lijun Wang, Z. Wang
In this paper, the behavior of high current vacuum arc under axial magnetic field (AMF) with different radial distributions, e.g., saddle shaped AMF and bell shaped AMF, are investigated. The different AMF distributions are implemented by adding ferromagnetic material (iron) into existing cup-shaped AMF electrodes. High current experiments have been conducted with these iron-style AMF electrodes. Images of the vacuum arc column and the distribution of cathode spots were photographed with a high-speed charge coupled device (CCD) camera. Experimental results indicate that non-uniformly distributed AMF with higher axial magnetic flux density at the contact periphery than that at the center (saddle shaped AMF) can resist arc constriction and increase the cathode and anode utilization ratios more effectively than ordinary bell shaped AMF profile.
{"title":"Experimental investigation of high current vacuum arc under non-uniformly distributed axial magnetic field","authors":"Z. Shi, S. Jia, Lijun Wang, Z. Wang","doi":"10.1109/DEIV.2004.1418645","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418645","url":null,"abstract":"In this paper, the behavior of high current vacuum arc under axial magnetic field (AMF) with different radial distributions, e.g., saddle shaped AMF and bell shaped AMF, are investigated. The different AMF distributions are implemented by adding ferromagnetic material (iron) into existing cup-shaped AMF electrodes. High current experiments have been conducted with these iron-style AMF electrodes. Images of the vacuum arc column and the distribution of cathode spots were photographed with a high-speed charge coupled device (CCD) camera. Experimental results indicate that non-uniformly distributed AMF with higher axial magnetic flux density at the contact periphery than that at the center (saddle shaped AMF) can resist arc constriction and increase the cathode and anode utilization ratios more effectively than ordinary bell shaped AMF profile.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125604811","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418607
U. Schumann, M. Kurrat
In this work, theoretical considerations concerning breakdown in the case of lightning impulse voltage ( 1.2/50μs) we investigated. Two breakdown Hypotheses are commonly available in publication. One is particle induced breakdown [1], where charged particles pass through the contact path. On contact with the anode, the induced processes lead to voltage collapse of the configuration. The other assumes that through field emission [2] current, micro tips knelt on the surface. An explosion of a micro tip leaves behind a micro plasma which induces the breakdown. Two breakdown types in the rear and front of the lightning impulse voltage can be recorded during dielectric tests of vacuum gaps to determine the electric strength. The breakdown processes should be compared considering their physical processes. The model should help to clarify which breakdown mechanism is more probable for the individual breakdown.
{"title":"Basic considerations concerning lightning impulse voltage breakdown in vacuum","authors":"U. Schumann, M. Kurrat","doi":"10.1109/DEIV.2004.1418607","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418607","url":null,"abstract":"In this work, theoretical considerations concerning breakdown in the case of lightning impulse voltage ( 1.2/50μs) we investigated. Two breakdown Hypotheses are commonly available in publication. One is particle induced breakdown [1], where charged particles pass through the contact path. On contact with the anode, the induced processes lead to voltage collapse of the configuration. The other assumes that through field emission [2] current, micro tips knelt on the surface. An explosion of a micro tip leaves behind a micro plasma which induces the breakdown. Two breakdown types in the rear and front of the lightning impulse voltage can be recorded during dielectric tests of vacuum gaps to determine the electric strength. The breakdown processes should be compared considering their physical processes. The model should help to clarify which breakdown mechanism is more probable for the individual breakdown.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134225318","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418644
E. Litvinov, A. Z. Nemirovskii
Analyze non-stationary processes on the cathode and in near cathode of area of a vacuum arch. Such processes can result in periodicity of occurrence of the centers of explosive emission in cathode spot.
分析了真空拱区阴极和近阴极的非平稳过程。这一过程会导致阴极点爆炸发射中心的周期性出现。
{"title":"Recycling of centers of explosive emission in a cathode spot of a vacuum arc","authors":"E. Litvinov, A. Z. Nemirovskii","doi":"10.1109/DEIV.2004.1418644","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418644","url":null,"abstract":"Analyze non-stationary processes on the cathode and in near cathode of area of a vacuum arch. Such processes can result in periodicity of occurrence of the centers of explosive emission in cathode spot.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123786637","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418643
C. Ding, M. Yamada, S. Yanabu
In order to clarify the instability phenomena of a low current in the vacuum, the optical characteristics of a low current vacuum arc was investigated by using Cu, CuCr, CuW CuBi, and AgWC electrodes. We measured the spectrum-line intensity distribution during arc discharging for each electrode. It was found that for Cu, CuCc CuBi, and AgWC electrodes, the total of the spectrum intensity from 300nm to 900 (i.e. evaporation quantity) increase in the order of Cu, CuCc CuBi, and AgWC, and the chopping current decrease in the same order. The spectrum intensity of pure Cu and Cu alloy was investigated. It was found that the intensity peak (Um) decrease in the order of Cu, CuCr and CuBi, but the chopping current did not increased in the same order. It decreased in the same order with the decline speed of the intensity (dU/dt). The chopping current is mainly determined by the evaporation quantity and the thermal properties of the additives in Cu alloy. We also observed the intensities during arc voltage oscillating for each electrode. It was found for every electrode that the oscillation voltage rises to the same direction with the arc voltage, and the spectrum intensity sharply decreases at the arc voltage oscillation. It supports the view that spotless discharge (a kind of glow discharge) occurred during this period.
{"title":"Optical observation on a low current instability in vacuum discharge","authors":"C. Ding, M. Yamada, S. Yanabu","doi":"10.1109/DEIV.2004.1418643","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418643","url":null,"abstract":"In order to clarify the instability phenomena of a low current in the vacuum, the optical characteristics of a low current vacuum arc was investigated by using Cu, CuCr, CuW CuBi, and AgWC electrodes. We measured the spectrum-line intensity distribution during arc discharging for each electrode. It was found that for Cu, CuCc CuBi, and AgWC electrodes, the total of the spectrum intensity from 300nm to 900 (i.e. evaporation quantity) increase in the order of Cu, CuCc CuBi, and AgWC, and the chopping current decrease in the same order. The spectrum intensity of pure Cu and Cu alloy was investigated. It was found that the intensity peak (Um) decrease in the order of Cu, CuCr and CuBi, but the chopping current did not increased in the same order. It decreased in the same order with the decline speed of the intensity (dU/dt). The chopping current is mainly determined by the evaporation quantity and the thermal properties of the additives in Cu alloy. We also observed the intensities during arc voltage oscillating for each electrode. It was found for every electrode that the oscillation voltage rises to the same direction with the arc voltage, and the spectrum intensity sharply decreases at the arc voltage oscillation. It supports the view that spotless discharge (a kind of glow discharge) occurred during this period.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130806835","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418622
M. Langlois
Polycrystalline alumina are extensively used in the vacuum electron tube industry. Depending on the tube type, they must satisfy some or all of the following requirements.
多晶氧化铝广泛应用于真空电子管工业。根据管的类型，它们必须满足以下部分或全部要求。
{"title":"Charge trapping in irradiated polycrystalline alumina","authors":"M. Langlois","doi":"10.1109/DEIV.2004.1418622","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418622","url":null,"abstract":"Polycrystalline alumina are extensively used in the vacuum electron tube industry. Depending on the tube type, they must satisfy some or all of the following requirements.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122095965","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418591
A. Murzakaev, Y. Yumaguzin
Nanopowders of copper were analysed by SEM, TEM, XRD and field electron emission methods. Investigation of electron emission from a copper nanopowder cathode has shown that emission characteristics were similar to ones from semiconductors.
{"title":"Emission characteristics of cathodes pressed from icopper nanopowders","authors":"A. Murzakaev, Y. Yumaguzin","doi":"10.1109/DEIV.2004.1418591","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418591","url":null,"abstract":"Nanopowders of copper were analysed by SEM, TEM, XRD and field electron emission methods. Investigation of electron emission from a copper nanopowder cathode has shown that emission characteristics were similar to ones from semiconductors.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114479065","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418619
Y. Stishkov, A. Buyanov, I. Elagin, M. A. Pavleyno, A. A. Statuya
In thb paper, the new algorithm for the unipolar corona discharge computation by the finite-element package ANSYS Is proposed. A wire-plane electrode arrangement has been chosen, as an example. The invariability of the electric Intensity force lines In the case of corona discharge in comparison with the case without discharge Is a fundamental assumption of this algorithm. So the distribution of electric intensity in the case of the corona discharge E cor along a force line can be expressed by the formula E cor = S E el , where E el is an electric intensity in the case without discharge, S is a some scalar function of coordinates. The computational algorithm consists of several stages. At the first stage the electric field distribution without taking into account a volume charge was calculated. At the following stage force lines were constructed and distributions of a volume charge and an electric field at corona discharge was calculated along these lines. Further, the current density distribution was specified so that drop of potential along whole force line was equal to the applied voltage, and new calculation was made with the specified value of a current. As these tasks are non-standard for ANSYS package, special programs were developed for their calculation in this package. At last stage the accuracy of received solution was estimated. Estimation has shown the solution satisfies to the Initial equations of corona discharge with accuracy about 10-15 %. Then calculated density of electric forces was used for the electric wind task solution, therefore pressure and velocity distributions were received.
本文提出了利用有限元软件ANSYS计算单极电晕放电的新算法。作为一个例子，我们选择了一种线-平面电极排列方式。电晕放电情况下与无放电情况下电强度线的不变性是该算法的一个基本假设。因此电晕放电情况下电强度沿力线的分布可以用公式E cor = S E el表示，其中E el是无放电情况下的电强度，S是坐标的标量函数。计算算法包括几个阶段。在第一阶段，计算了不考虑体积电荷的电场分布。在接下来的阶段，构造了力线，并沿这些线计算了电晕放电时体积电荷和电场的分布。进一步，指定电流密度分布，使整个力线上的电势降等于外加电压，并以指定的电流值重新计算。由于这些任务在ANSYS包中是非标准的，因此在ANSYS包中开发了专门的计算程序。最后对接收溶液的精度进行了估计。计算结果表明，该解满足电晕放电的初始方程，精度约为10- 15%。然后将计算得到的电力密度用于电风任务解，从而得到压力和速度分布。
{"title":"Methods of electric discharge modeling by ANSYS package","authors":"Y. Stishkov, A. Buyanov, I. Elagin, M. A. Pavleyno, A. A. Statuya","doi":"10.1109/DEIV.2004.1418619","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418619","url":null,"abstract":"In thb paper, the new algorithm for the unipolar corona discharge computation by the finite-element package ANSYS Is proposed. A wire-plane electrode arrangement has been chosen, as an example. The invariability of the electric Intensity force lines In the case of corona discharge in comparison with the case without discharge Is a fundamental assumption of this algorithm. So the distribution of electric intensity in the case of the corona discharge E cor along a force line can be expressed by the formula E cor = S E el , where E el is an electric intensity in the case without discharge, S is a some scalar function of coordinates. The computational algorithm consists of several stages. At the first stage the electric field distribution without taking into account a volume charge was calculated. At the following stage force lines were constructed and distributions of a volume charge and an electric field at corona discharge was calculated along these lines. Further, the current density distribution was specified so that drop of potential along whole force line was equal to the applied voltage, and new calculation was made with the specified value of a current. As these tasks are non-standard for ANSYS package, special programs were developed for their calculation in this package. At last stage the accuracy of received solution was estimated. Estimation has shown the solution satisfies to the Initial equations of corona discharge with accuracy about 10-15 %. Then calculated density of electric forces was used for the electric wind task solution, therefore pressure and velocity distributions were received.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132734677","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418641
A. Batrakov, B. Juettner, S. Popov, D. Proskurovsky, N. Vogel
The resonant laser diagnostics combined with high speed IMACON 468 frame/streak camera was used as a technique for data acquisition. The experiments were performed with an arced vacuum gap formed by the capillary-type liquid-metal cathode and the plane anode in conditions of high oil-free vacuum. The evolution of observable cathode spot plasma is analysed in terms of cyclicity of the cathode spot operation.
{"title":"Time resolved resonant laser diagnostics of the low current vacuum arc cathode spot","authors":"A. Batrakov, B. Juettner, S. Popov, D. Proskurovsky, N. Vogel","doi":"10.1109/DEIV.2004.1418641","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418641","url":null,"abstract":"The resonant laser diagnostics combined with high speed IMACON 468 frame/streak camera was used as a technique for data acquisition. The experiments were performed with an arced vacuum gap formed by the capillary-type liquid-metal cathode and the plane anode in conditions of high oil-free vacuum. The evolution of observable cathode spot plasma is analysed in terms of cyclicity of the cathode spot operation.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132756024","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418636
S. Gorbunov, V. Krasov, V. Paperny, Y. Rusakov
Ion velocities in cathode plasma flow of a low voltage vacuum spark have been studied experimentally for peak discharge currents of 1 - 10 kA. Experiments have been performed using the time-of-flight technique at different ranges of ion collector from the discharge gap. It is shown that there are two ion components in the cathode flow. The slow one presents the bulk of ion distribution and at low peak discharge current its velocity is closed to the convenient value for vacuum arc. The fast components¿ velocity is a few times higher than one for slow ions and amplitude of current for these ions at a range of 10 cm from the discharge gap was closed to one for the slow component. As the distance increases, peak of the fast ions decreases sharper than one for the slow component. Amplitudes of signals and mean velocities of both ion components increase sharply with the discharge current. The fast ion component corresponds, apparently, to beam of the multiply charged ions that had been found by the authors earlier. Total amount of these ions attains, approximately, 1013 ions per a pulse.
{"title":"Two-components ion flow in a low voltage vacuum spark","authors":"S. Gorbunov, V. Krasov, V. Paperny, Y. Rusakov","doi":"10.1109/DEIV.2004.1418636","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418636","url":null,"abstract":"Ion velocities in cathode plasma flow of a low voltage vacuum spark have been studied experimentally for peak discharge currents of 1 - 10 kA. Experiments have been performed using the time-of-flight technique at different ranges of ion collector from the discharge gap. It is shown that there are two ion components in the cathode flow. The slow one presents the bulk of ion distribution and at low peak discharge current its velocity is closed to the convenient value for vacuum arc. The fast components¿ velocity is a few times higher than one for slow ions and amplitude of current for these ions at a range of 10 cm from the discharge gap was closed to one for the slow component. As the distance increases, peak of the fast ions decreases sharper than one for the slow component. Amplitudes of signals and mean velocities of both ion components increase sharply with the discharge current. The fast ion component corresponds, apparently, to beam of the multiply charged ions that had been found by the authors earlier. Total amount of these ions attains, approximately, 1013 ions per a pulse.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130450539","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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