Pub Date : 2004-09-27DOI: 10.1109/DEIV.2004.1418656
D. Shmelev
The 2D magnetohydrodynamic model of the low current vacuum arc under action of strong axial magnetic field (AMF) is presented. It is supposed that modelled low current arc (LCA) is the part of high current vacuum arc, witch operate in multicathode spot mode and can be treated as the array of independently burning LCA.
{"title":"Low current vacuum arc in strong axial magnetic field","authors":"D. Shmelev","doi":"10.1109/DEIV.2004.1418656","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418656","url":null,"abstract":"The 2D magnetohydrodynamic model of the low current vacuum arc under action of strong axial magnetic field (AMF) is presented. It is supposed that modelled low current arc (LCA) is the part of high current vacuum arc, witch operate in multicathode spot mode and can be treated as the array of independently burning LCA.","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":"128797965","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.2004.1418652
N. S. Lomino, V. Ovcharenko, A. Andreev
The parameters of metallic plasma in the interelectrode gap of the vacuum-arc discharge in the wide range of gas pressures are studied. For diagnostics the methods of emission spectroscopy and electric probes were used. In the range of pressures p=(1 ÷ 10) Pa the action of a mechanism of activation (excitation and ionization) of metal (Ti) ions and atoms was observed. This mechanism is realized under interaction of erosion products released from the cathode spot together with excited gas particles. The energy transfer from gas particles to titanium particles beginning in the form of microdrops and neutral vapors and ions leads to drop evaporation and additional excitation and ionization of metal vapors and ions and, in some ranges of gas pressure, to the significant increase of titanium ion concentrations. Possibility to develop the mechanism of plasmochemical synthesis of metal-gas compounds in the range of gas pressures p ≫ 1 Pa not on the substrate with applying the bias potential but in the plasma volume with formation of fine-dispersed dust is discussed.
{"title":"On mechanism of vacuum-arc plasma activation in the range of pressures 1 ÷ 10 Pa","authors":"N. S. Lomino, V. Ovcharenko, A. Andreev","doi":"10.1109/DEIV.2004.1418652","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418652","url":null,"abstract":"The parameters of metallic plasma in the interelectrode gap of the vacuum-arc discharge in the wide range of gas pressures are studied. For diagnostics the methods of emission spectroscopy and electric probes were used. In the range of pressures p=(1 ÷ 10) Pa the action of a mechanism of activation (excitation and ionization) of metal (Ti) ions and atoms was observed. This mechanism is realized under interaction of erosion products released from the cathode spot together with excited gas particles. The energy transfer from gas particles to titanium particles beginning in the form of microdrops and neutral vapors and ions leads to drop evaporation and additional excitation and ionization of metal vapors and ions and, in some ranges of gas pressure, to the significant increase of titanium ion concentrations. Possibility to develop the mechanism of plasmochemical synthesis of metal-gas compounds in the range of gas pressures p ≫ 1 Pa not on the substrate with applying the bias potential but in the plasma volume with formation of fine-dispersed dust is discussed.","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":"130988363","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.2004.1418638
I.I. Belis, A. Shahurin, A. Nemirovsky, S. Goldsmith, R. Boxman
The temperature distribution in symmetric and asymmetric molybdenum anodes of a Hot Refractory Anode Vacuum Arc was determined using high temperature thermocouple probes placed in three locations in the anode body. Three different anode geometries were used, with arc currents in the range 125 - 225 A, and electrode separations of 5 -18 mm. The anode temperature increased with arc current and decreased with the electrode separation. The steady state anode surface temperature exceeded 2200-2300K for currents larger than 150A. Photographic study of the interelectrode region indicated that during the transition period to the Hot Anode mode the plasma plume was asymmetrically distributed on the asymmetric anode surface, resulting in an asymmetric anode surface temperature distribution.
{"title":"Measurements of the molybdenum anode temperature in a hot refractory anode vacuum are","authors":"I.I. Belis, A. Shahurin, A. Nemirovsky, S. Goldsmith, R. Boxman","doi":"10.1109/DEIV.2004.1418638","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418638","url":null,"abstract":"The temperature distribution in symmetric and asymmetric molybdenum anodes of a Hot Refractory Anode Vacuum Arc was determined using high temperature thermocouple probes placed in three locations in the anode body. Three different anode geometries were used, with arc currents in the range 125 - 225 A, and electrode separations of 5 -18 mm. The anode temperature increased with arc current and decreased with the electrode separation. The steady state anode surface temperature exceeded 2200-2300K for currents larger than 150A. Photographic study of the interelectrode region indicated that during the transition period to the Hot Anode mode the plasma plume was asymmetrically distributed on the asymmetric anode surface, resulting in an asymmetric anode surface temperature distribution.","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":"114354919","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.2004.1418640
A. Batrakov, B. Juettner, E. Pryadko
Some of droplets emitted by vacuum arc cathode spot and surrounded by dense plasma were suggested recently to be referred to as droplet spots. Droplet spot plasma temperature and concentration are close to those of the cathode spot plasma. The goal of this work is study of spectral characteristics of droplet spot light emission. High-speed imaging based on an IMACON 468 camera in combination with narrow-banded interference filter was used for getting spectrum. Droplet spot spectrum was compared with cathode spot one taken in the same experiments. Comparison revealed resemblance in the spectrums. Second part of the work describes light emission dynamics of droplet spots after arc discharge extinction. It has been found that brightness in visible an IR light of some droplets grows in time during tens to hundreds microseconds after discharge extinction, then it decreases gradually. The most intriguing fact is that a cycle of growing brightness is followed sometimes by a repeated cycle (and even a few cycles).
{"title":"Investigation into light emission from droplet spots produced by low-current vacuum are discharge","authors":"A. Batrakov, B. Juettner, E. Pryadko","doi":"10.1109/DEIV.2004.1418640","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418640","url":null,"abstract":"Some of droplets emitted by vacuum arc cathode spot and surrounded by dense plasma were suggested recently to be referred to as droplet spots. Droplet spot plasma temperature and concentration are close to those of the cathode spot plasma. The goal of this work is study of spectral characteristics of droplet spot light emission. High-speed imaging based on an IMACON 468 camera in combination with narrow-banded interference filter was used for getting spectrum. Droplet spot spectrum was compared with cathode spot one taken in the same experiments. Comparison revealed resemblance in the spectrums. Second part of the work describes light emission dynamics of droplet spots after arc discharge extinction. It has been found that brightness in visible an IR light of some droplets grows in time during tens to hundreds microseconds after discharge extinction, then it decreases gradually. The most intriguing fact is that a cycle of growing brightness is followed sometimes by a repeated cycle (and even a few cycles).","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":"114763088","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.2004.1418595
A. Batrakov, D.J. Johnson, S. Onischenko, D. Proskurovsky
The paper describes the results of study of prebreakdown emission in vacuum and correlations between prebreakdown emission sites and breakdown of gaps formed by plane-parallel electrodes made of stainless steels. Anode-scanning probe vas used for recognizing emission sites and reconstructing emission maps of 8-cm-diameter plane cathodes. After recognizing emission sites, high-voltage 60-ns 220-kV square pulses were applied with closing a gap until breakdown occurs. Cathode emission sites were found experimentally to be responsible for electrical breakdown at hold-off electric field essentially below 1 MV/cm. In a case of better insulating ability of a vacuum gap, the anode becomes more influencing on electrical insulation of a gap.
{"title":"Investigation of breakdown emission sites on the surface of large-area stainless-steel cathodes in vacuum","authors":"A. Batrakov, D.J. Johnson, S. Onischenko, D. Proskurovsky","doi":"10.1109/DEIV.2004.1418595","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418595","url":null,"abstract":"The paper describes the results of study of prebreakdown emission in vacuum and correlations between prebreakdown emission sites and breakdown of gaps formed by plane-parallel electrodes made of stainless steels. Anode-scanning probe vas used for recognizing emission sites and reconstructing emission maps of 8-cm-diameter plane cathodes. After recognizing emission sites, high-voltage 60-ns 220-kV square pulses were applied with closing a gap until breakdown occurs. Cathode emission sites were found experimentally to be responsible for electrical breakdown at hold-off electric field essentially below 1 MV/cm. In a case of better insulating ability of a vacuum gap, the anode becomes more influencing on electrical insulation of a gap.","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":"117169470","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.2004.1418650
M. B. Bochkarev
A copper vacuum arc cathode spot at current 3-12 A was imaged by streak camera with time resolution up to 0.7 ns and spatial resolution up to 2.9 μm. It was found that for copper at currents of two threshold current (3A) the most probable duration of ecton cycle is 15- 20 ns and the duration of phase of intense plasma production is 5 - 10 ns. As current rises the ectons having more long cycle duration and more long phase of intense plasma production appears, so that at current of eight threshold current (12 A) the most probable duration of ecton cycle is 50- 70 ns and the duration of phase of intense plasma production is 10-20 ns. The ectons with shortest cycle time still appears at 12 A current.
{"title":"Ecton processes of low current vacuum arc imaged with streak technique","authors":"M. B. Bochkarev","doi":"10.1109/DEIV.2004.1418650","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418650","url":null,"abstract":"A copper vacuum arc cathode spot at current 3-12 A was imaged by streak camera with time resolution up to 0.7 ns and spatial resolution up to 2.9 μm. It was found that for copper at currents of two threshold current (3A) the most probable duration of ecton cycle is 15- 20 ns and the duration of phase of intense plasma production is 5 - 10 ns. As current rises the ectons having more long cycle duration and more long phase of intense plasma production appears, so that at current of eight threshold current (12 A) the most probable duration of ecton cycle is 50- 70 ns and the duration of phase of intense plasma production is 10-20 ns. The ectons with shortest cycle time still appears at 12 A current.","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":"132088834","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.2004.1418585
L. Baskin
Currently, there is considerable interest in field emission from thin carbon films and diamond-like structures as well as from systems containing fullerenes and nanotubes [ 1, 3-7, 15- 19]. Such systems are likely to find wide application in the low-voltage cold cathodes, used as sources of electrons in electro- vacuum devices, primarily in flat displays providing images of high brightness. Usually such systems are investigated in plane geometry (the cathode is taken to be a flat film positioned a distance d from the anode with a potential Va). In all such systems the field emission is initiated by anomalously small fields.
{"title":"Field emission of broadband semiconductors and dielectrics","authors":"L. Baskin","doi":"10.1109/DEIV.2004.1418585","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418585","url":null,"abstract":"Currently, there is considerable interest in field emission from thin carbon films and diamond-like structures as well as from systems containing fullerenes and nanotubes [ 1, 3-7, 15- 19]. Such systems are likely to find wide application in the low-voltage cold cathodes, used as sources of electrons in electro- vacuum devices, primarily in flat displays providing images of high brightness. Usually such systems are investigated in plane geometry (the cathode is taken to be a flat film positioned a distance d from the anode with a potential Va). In all such systems the field emission is initiated by anomalously small fields.","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":"121366860","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.2004.1418649
S. Suzuki, E. Kaneko, S. Kobayashi, S. Yanabu
It is well known that axial magnetic field electrodes can interrupt higher current than other types of electrode. The arcs in the electrode spread uniformly in the inter-electrode space and, thus, the electrodes are hardly damaged by the arcs. As interruption tests of the axial magnetic electrodes indicate, CuCr has higher interruption capability than CuBi. Some differences of arc appearances between CuBi and CuCr vacuum arcs might he expected. To clarify these differences, we conducted arc observation tests of axial magnetic field electrodes with CuBi or CuCr contact material using a de-mountable chamber. We used digital high speed CCD video-cameras with and without infrared sensitivity, and set them to observe the vacuum arcs obliquely toward anode or cathode electrodes. The diameter of these electrodes was 52 mm. If we use these electrodes, interruption of 30-35kA of crest value is expected for CuCr electrode and much less is expected for CuBi electrode. Following phenomena were observed. 1) Many bright spots with visible size were observed during arcing period in CuBi electrodes, not in CuCr electrodes. 2) Big difference was not observed in arc distribution between CuBi and CuCr electrodes. 3) Uneven distributions of infra-red images on the electrode surface were observed in high arc current periods. These are suggesting the reasons of CuCr's higher capability of current interruption.
{"title":"Difference of vacuum arc appearance between CuBi and CuCr electrodes","authors":"S. Suzuki, E. Kaneko, S. Kobayashi, S. Yanabu","doi":"10.1109/DEIV.2004.1418649","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418649","url":null,"abstract":"It is well known that axial magnetic field electrodes can interrupt higher current than other types of electrode. The arcs in the electrode spread uniformly in the inter-electrode space and, thus, the electrodes are hardly damaged by the arcs. As interruption tests of the axial magnetic electrodes indicate, CuCr has higher interruption capability than CuBi. Some differences of arc appearances between CuBi and CuCr vacuum arcs might he expected. To clarify these differences, we conducted arc observation tests of axial magnetic field electrodes with CuBi or CuCr contact material using a de-mountable chamber. We used digital high speed CCD video-cameras with and without infrared sensitivity, and set them to observe the vacuum arcs obliquely toward anode or cathode electrodes. The diameter of these electrodes was 52 mm. If we use these electrodes, interruption of 30-35kA of crest value is expected for CuCr electrode and much less is expected for CuBi electrode. Following phenomena were observed. 1) Many bright spots with visible size were observed during arcing period in CuBi electrodes, not in CuCr electrodes. 2) Big difference was not observed in arc distribution between CuBi and CuCr electrodes. 3) Uneven distributions of infra-red images on the electrode surface were observed in high arc current periods. These are suggesting the reasons of CuCr's higher capability of current interruption.","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":"127764690","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.2004.1418639
Lijun Wang, S. Jia, Z. Shi, M. Rong
Based on two-fluid models of ion, electron and Maxwell equation, The two-dimensional magnetohydrodynamic (MHD) model of vacuum arc was obtained in this paper, In the MHD model, mass conservation equation, momentum conservation equations, energy conservation equations, Maxwell equation and generalized ohm¿s law were considered. By numerically calculating above equations, the plasma parameters of vacuum arc were obtained. According to the calculation results, The influence of azimuthal self-magnetic field and different radial distributed axial magnetic field. (AMF) on vacuum arc plasma parameters were analyzed.
{"title":"MHD simulation of vacuum arc under different AMF","authors":"Lijun Wang, S. Jia, Z. Shi, M. Rong","doi":"10.1109/DEIV.2004.1418639","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418639","url":null,"abstract":"Based on two-fluid models of ion, electron and Maxwell equation, The two-dimensional magnetohydrodynamic (MHD) model of vacuum arc was obtained in this paper, In the MHD model, mass conservation equation, momentum conservation equations, energy conservation equations, Maxwell equation and generalized ohm¿s law were considered. By numerically calculating above equations, the plasma parameters of vacuum arc were obtained. According to the calculation results, The influence of azimuthal self-magnetic field and different radial distributed axial magnetic field. (AMF) on vacuum arc plasma parameters were analyzed.","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":"127331861","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.2004.1418657
I. Muzukin
Temporal behavior of a high-energy electron flow from area of a vacuum arc was explored. Electrons emanating from area of the cathode with the energies essentially exceeding a voltage drop on the discharge are revealed. Correlation of cruption outbursts of a high-energy electron flow and instabilities of a current of the discharge is revealed. Joint oscillograms of a flow of electrons under different directions to the cathode surface also were obtained.
{"title":"Temporal measurements of an accelerated electron flow from area of a vacuum arc","authors":"I. Muzukin","doi":"10.1109/DEIV.2004.1418657","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418657","url":null,"abstract":"Temporal behavior of a high-energy electron flow from area of a vacuum arc was explored. Electrons emanating from area of the cathode with the energies essentially exceeding a voltage drop on the discharge are revealed. Correlation of cruption outbursts of a high-energy electron flow and instabilities of a current of the discharge is revealed. Joint oscillograms of a flow of electrons under different directions to the cathode surface also were obtained.","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":"121704013","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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