A. Nishimura, Y. Hishinuma, K. Seo, Teruya Tanaka, T. Muroga, S. Nishijima, K. Katagiri, T. Takeuchi, Y. Shindo, K. Ochiai, T. Nishitani, K. Okuno
As a large‐scale plasma experimental device is planned and designed, the importance of investigations on irradiation effect of 14 MeV neutron increases and an experimental database is desired to be piled up. Recently, intense streaming of fast neutron from ports are reported and degradation of superconducting magnet performance is anticipated. To investigate the pure neutron effect on superconducting magnet materials, a cryogenic target system was newly developed and installed at Fusion Neutronics Source in Japan Atomic Energy Research Institute. Although production rate of 14 MeV neutron is not large, only 14 MeV neutron can be supplied to irradiation test without gamma ray. Copper wires, superconducting wires, glass fiber reinforced composites are irradiated and the irradiation effects are characterized. At the same time, sensors for measuring temperature and magnetic field are irradiated and their performance was investigated after irradiation. This paper presents outline of the cryogenic target system and some irradiation test results.
{"title":"14 MeV Neutron Irradiation Effect on Superconducting Magnet Materials for Fusion Device","authors":"A. Nishimura, Y. Hishinuma, K. Seo, Teruya Tanaka, T. Muroga, S. Nishijima, K. Katagiri, T. Takeuchi, Y. Shindo, K. Ochiai, T. Nishitani, K. Okuno","doi":"10.1063/1.2192353","DOIUrl":"https://doi.org/10.1063/1.2192353","url":null,"abstract":"As a large‐scale plasma experimental device is planned and designed, the importance of investigations on irradiation effect of 14 MeV neutron increases and an experimental database is desired to be piled up. Recently, intense streaming of fast neutron from ports are reported and degradation of superconducting magnet performance is anticipated. To investigate the pure neutron effect on superconducting magnet materials, a cryogenic target system was newly developed and installed at Fusion Neutronics Source in Japan Atomic Energy Research Institute. Although production rate of 14 MeV neutron is not large, only 14 MeV neutron can be supplied to irradiation test without gamma ray. Copper wires, superconducting wires, glass fiber reinforced composites are irradiated and the irradiation effects are characterized. At the same time, sensors for measuring temperature and magnetic field are irradiated and their performance was investigated after irradiation. This paper presents outline of the cryogenic target system and some irradiation test results.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"208-215"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192353","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59396573","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}
High field magnet coils made from brittle A15 superconductors need to be rigidly contained by their support structure but yet be electrically insulated from it. Current insulators (end shoes, pole pieces, spacers, mandrels, etc.) are often made from coated metallic shapes that satisfy the mechanical and thermal requirements but are electrically unreliable. The insulating coating on the metal core too often chips or flakes, causing electrical shorts. Any replacement insulator materials must manage the thermal expansion mismatch to control the stress within the coil enabling the achievement of ultimate magnet performance.A novel ceramic insulator has been developed that eliminates the potential for shorting while maintaining high structural integrity and thermal performance. The insulator composition can be engineered to provide a thermal expansion that matches the coil expansion, minimizing detrimental stress on the superconductor. These ceramic insulators are capable of surviving high temperature heat tre...
{"title":"Engineered Ceramic Insulators for High Field Magnets","authors":"J. Rice","doi":"10.1063/1.2192363","DOIUrl":"https://doi.org/10.1063/1.2192363","url":null,"abstract":"High field magnet coils made from brittle A15 superconductors need to be rigidly contained by their support structure but yet be electrically insulated from it. Current insulators (end shoes, pole pieces, spacers, mandrels, etc.) are often made from coated metallic shapes that satisfy the mechanical and thermal requirements but are electrically unreliable. The insulating coating on the metal core too often chips or flakes, causing electrical shorts. Any replacement insulator materials must manage the thermal expansion mismatch to control the stress within the coil enabling the achievement of ultimate magnet performance.A novel ceramic insulator has been developed that eliminates the potential for shorting while maintaining high structural integrity and thermal performance. The insulator composition can be engineered to provide a thermal expansion that matches the coil expansion, minimizing detrimental stress on the superconductor. These ceramic insulators are capable of surviving high temperature heat tre...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"291-297"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59397070","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}
The cryogenic damage and fracture properties of GFRP (glass fiber reinforced polymer) woven laminates has been investigated theoretically and experimentally. Three‐point bend tests were carried out with SENB (single‐edge‐notched bend) specimens at room temperature, liquid nitrogen temperature and liquid helium temperature. SENB specimens with different widths and thicknesses were prepared and tested. The results of SENB specimens were compared with those of CT (compact tension) specimens. A finite element analysis was also conducted to predict the response of the damaged SENB specimen. Effective elastic moduli were determined under the assumption of uniform strain inside the representative volume element. Hoffman failure criterion was selected as the criterion for fiber‐dominated failure, and matrix microcracking was detected by the maximum strain criterion. The virtual crack extension method was adopted to calculate strain energy release rate which leads to determination of stress intensity factor. In order to verify the model, correlations between experimental and analytical results were made, in terms of the load‐displacement response and the extent of damage growth. Reasonable agreements were found between the calculations and the experimental data.
{"title":"Notched Three‐Point Bend Testing of GFRP Woven Laminates at Cryogenic Temperatures and Analysis of Fracture and Damage Properties","authors":"K. Sanada, Y. Shindo","doi":"10.1063/1.2192360","DOIUrl":"https://doi.org/10.1063/1.2192360","url":null,"abstract":"The cryogenic damage and fracture properties of GFRP (glass fiber reinforced polymer) woven laminates has been investigated theoretically and experimentally. Three‐point bend tests were carried out with SENB (single‐edge‐notched bend) specimens at room temperature, liquid nitrogen temperature and liquid helium temperature. SENB specimens with different widths and thicknesses were prepared and tested. The results of SENB specimens were compared with those of CT (compact tension) specimens. A finite element analysis was also conducted to predict the response of the damaged SENB specimen. Effective elastic moduli were determined under the assumption of uniform strain inside the representative volume element. Hoffman failure criterion was selected as the criterion for fiber‐dominated failure, and matrix microcracking was detected by the maximum strain criterion. The virtual crack extension method was adopted to calculate strain energy release rate which leads to determination of stress intensity factor. In order to verify the model, correlations between experimental and analytical results were made, in terms of the load‐displacement response and the extent of damage growth. Reasonable agreements were found between the calculations and the experimental data.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"264-271"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192360","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59397101","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}
R. Prokopec, K. Humer, H. Fillunger, R. Maix, H. Weber
Fiber reinforced plastics will be used as insulation systems for the superconducting magnet coils of ITER. The fast neutron and gamma radiation environment present at the magnet location will lead to serious material degradation, particularly of the insulation. For this reason, advanced radiation‐hard resin systems are of special interest. In this study various R‐glass fiber / Kapton reinforced DGEBA epoxy and cyanate ester composites fabricated by the vacuum pressure impregnation method were investigated. All systems were irradiated at ambient temperature (340 K) in the TRIGA reactor (Vienna) to a fast neutron fluence of 1×1022 m−2 (E>0.1 MeV). Short‐beam shear and static tensile tests were carried out at 77 K prior to and after irradiation. In addition, tension‐tension fatigue measurements were used in order to assess the mechanical performance of the insulation systems under the pulsed operation conditions of ITER. For the cyanate ester based system the influence of interleaving Kapton layers on the st...
{"title":"Static and Dynamic Performance of Newly Developed ITER Relevant Insulation Systems after Neutron Irradiation","authors":"R. Prokopec, K. Humer, H. Fillunger, R. Maix, H. Weber","doi":"10.1063/1.2192370","DOIUrl":"https://doi.org/10.1063/1.2192370","url":null,"abstract":"Fiber reinforced plastics will be used as insulation systems for the superconducting magnet coils of ITER. The fast neutron and gamma radiation environment present at the magnet location will lead to serious material degradation, particularly of the insulation. For this reason, advanced radiation‐hard resin systems are of special interest. In this study various R‐glass fiber / Kapton reinforced DGEBA epoxy and cyanate ester composites fabricated by the vacuum pressure impregnation method were investigated. All systems were irradiated at ambient temperature (340 K) in the TRIGA reactor (Vienna) to a fast neutron fluence of 1×1022 m−2 (E>0.1 MeV). Short‐beam shear and static tensile tests were carried out at 77 K prior to and after irradiation. In addition, tension‐tension fatigue measurements were used in order to assess the mechanical performance of the insulation systems under the pulsed operation conditions of ITER. For the cyanate ester based system the influence of interleaving Kapton layers on the st...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"342-348"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192370","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59397161","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}
This report presents preliminary results of a project with the aim to fabricate fine‐grained tantalum sheet having a uniform microstructure that co‐deforms well with pure copper for superconductor diffusion barrier applications. Multi‐pass equal channel angular extrusion (ECAE) was used to refine the microstructure of 25 mm square cross‐section bars of Ta; rolling was used to convert the bars to 0.38 mm thick sheet. Cu‐Ta co‐deformation characteristics were evaluated by assembling and drawing experimental Cu‐Ta composite wires, containing the ECAE processed sheets, to 0.83 mm diameter and metallographically examining the thinned 2–4 micron Ta layer. The ECAE processed Ta sheet co‐deformed well with Cu, and was found to have a smaller recrystallized grain size, a narrower grain size distribution and a slightly higher hardness compared to commercial diffusion barrier grade Ta sheet. The favorable results encourage further work.
{"title":"Tantalum Sheet for Superconductor Diffusion Barrier Applications","authors":"S. Mathaudhu, K. Hartwig, R. E. Barber, T. Pyon","doi":"10.1063/1.2192399","DOIUrl":"https://doi.org/10.1063/1.2192399","url":null,"abstract":"This report presents preliminary results of a project with the aim to fabricate fine‐grained tantalum sheet having a uniform microstructure that co‐deforms well with pure copper for superconductor diffusion barrier applications. Multi‐pass equal channel angular extrusion (ECAE) was used to refine the microstructure of 25 mm square cross‐section bars of Ta; rolling was used to convert the bars to 0.38 mm thick sheet. Cu‐Ta co‐deformation characteristics were evaluated by assembling and drawing experimental Cu‐Ta composite wires, containing the ECAE processed sheets, to 0.83 mm diameter and metallographically examining the thinned 2–4 micron Ta layer. The ECAE processed Ta sheet co‐deformed well with Cu, and was found to have a smaller recrystallized grain size, a narrower grain size distribution and a slightly higher hardness compared to commercial diffusion barrier grade Ta sheet. The favorable results encourage further work.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"590-598"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192399","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59398548","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}
Y. Hishinuma, A. Kikuchi, Y. Iijima, Y. Yoshida, T. Takeuchi, Kiyoshi Inoue, A. Nishimura
We have tried to study low activation superconducting materials of the many V‐based compound superconductors, and selected the V based Laves phase (V2(Hf,Zr)) compound because of its high upper critical field (Hc2) exceeding 20 T, its neutron irradiation resistance, and its low activation in the fusion reactor compared with those of Nb‐based A15 wires.The fabrication, microstructure and superconductivity of V2(Hf,Zr) multifilamentary wire synthesized by applying a rapidly‐heating/quenching (RHQ) and annealing process to the simple precursor using pure Hf and Zr mixture powder and pure V tube matrix were investigated. We found that a thick reaction layer was formed between the powder mixture filament and V matrix after the RHQ treatment and then it was increased with an increment of heating energy. Offset Tc values of samples were raised by increasing heating energy, and maximum Tc values occurred at 8.3 K. The maximum Jc value was obtained for a sample of post‐annealing at 600°C for 10 h. Jc dependence on...
{"title":"Microstructure and Superconducting Properties of V-Based Laves Phase Compound Multifilamentary Wires Synthesized by a Rapidly Heating and Quenching Process to Hf-Zr/V Composite","authors":"Y. Hishinuma, A. Kikuchi, Y. Iijima, Y. Yoshida, T. Takeuchi, Kiyoshi Inoue, A. Nishimura","doi":"10.1063/1.2192401","DOIUrl":"https://doi.org/10.1063/1.2192401","url":null,"abstract":"We have tried to study low activation superconducting materials of the many V‐based compound superconductors, and selected the V based Laves phase (V2(Hf,Zr)) compound because of its high upper critical field (Hc2) exceeding 20 T, its neutron irradiation resistance, and its low activation in the fusion reactor compared with those of Nb‐based A15 wires.The fabrication, microstructure and superconductivity of V2(Hf,Zr) multifilamentary wire synthesized by applying a rapidly‐heating/quenching (RHQ) and annealing process to the simple precursor using pure Hf and Zr mixture powder and pure V tube matrix were investigated. We found that a thick reaction layer was formed between the powder mixture filament and V matrix after the RHQ treatment and then it was increased with an increment of heating energy. Offset Tc values of samples were raised by increasing heating energy, and maximum Tc values occurred at 8.3 K. The maximum Jc value was obtained for a sample of post‐annealing at 600°C for 10 h. Jc dependence on...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"607-614"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192401","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59398728","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}
Cycled applied field magnetization curves contain a wealth of information on critical current density and flux pinning that is not commonly exploited. Detailed magnetization data for magnesium boride wire cores have been analyzed for critical state model consistency. The iron‐sheathed silicon nitride doped magnesium boride wires were prepared from pure magnesium and boron powders with nano‐scale silicon nitride additions (MgB2−x(Si3N4)x/7 with x = 0 – 0.4). A subsequent short annealing heat treatment, 800 degrees C and of 1 hour duration in Argon, was applied to create the desired phase. Magnetization critical current densities were up to ∼340 kA/cm2 at 5K and 1T. Major and minor loop analysis will be described, for field sweeps up to 3 tesla at fixed temperatures and for temperature sweeps from 5K to 45K in fixed fields, with respect to parameters describing the critical state model.
循环外加磁场磁化曲线包含了大量关于临界电流密度和磁通钉接的信息，这些信息通常不被利用。对硼化镁铁芯的详细磁化数据进行了临界状态模型一致性分析。以纯镁和硼粉为原料，加入纳米级氮化硅(MgB2−x(Si3N4)x/7, x = 0 ~ 0.4)，制备了铁包覆氮化硅掺杂硼化镁线。随后在氩气中进行800℃、持续1小时的短退火热处理，以产生所需的相。在5K和1T下，磁化临界电流密度高达~ 340 kA/cm2。根据描述临界状态模型的参数，将描述在固定温度下高达3特斯拉的场扫描和在固定场中从5K到45K的温度扫描的主回路和小回路分析。
{"title":"Magnetization Analysis of Magnesium Boride Wires","authors":"J. Cave, W. Zhu","doi":"10.1063/1.2192406","DOIUrl":"https://doi.org/10.1063/1.2192406","url":null,"abstract":"Cycled applied field magnetization curves contain a wealth of information on critical current density and flux pinning that is not commonly exploited. Detailed magnetization data for magnesium boride wire cores have been analyzed for critical state model consistency. The iron‐sheathed silicon nitride doped magnesium boride wires were prepared from pure magnesium and boron powders with nano‐scale silicon nitride additions (MgB2−x(Si3N4)x/7 with x = 0 – 0.4). A subsequent short annealing heat treatment, 800 degrees C and of 1 hour duration in Argon, was applied to create the desired phase. Magnetization critical current densities were up to ∼340 kA/cm2 at 5K and 1T. Major and minor loop analysis will be described, for field sweeps up to 3 tesla at fixed temperatures and for temperature sweeps from 5K to 45K in fixed fields, with respect to parameters describing the critical state model.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"646-653"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192406","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59398999","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}
Progress in manufacturing 40m long YBCO coated stainless steel tapes by ion beam assisted deposition and by high‐rate pulsed laser deposition is reported. A critical current of 84.5A (77K, self field) was observed for end‐to‐end measurements of the 40m long tape based on a 1.05μm thick and 3.6mm wide YBCO film. This implies that a critical current of 235A per cm‐width is achieved by just a 1 μm thick YBCO layer. Analysis of the influence of local defects onto the integral U(I) curves allowed to formulate a general criterion for the homogeneity in terms of reduced number of tape parameters.A deterioration of tapes induced by mechanical torsion starts at a very high deformation degree: irreversibility threshold corresponds to 3000 angular degrees per meter for 4mm wide coated tape loaded with a 40N tensile axial force.
{"title":"Long‐Length YBCO Coated Stainless Steel Tapes with High Critical Currents","authors":"A. Usoskin, A. Rutt, J. Knoke, R. Dietrich","doi":"10.1063/1.2192414","DOIUrl":"https://doi.org/10.1063/1.2192414","url":null,"abstract":"Progress in manufacturing 40m long YBCO coated stainless steel tapes by ion beam assisted deposition and by high‐rate pulsed laser deposition is reported. A critical current of 84.5A (77K, self field) was observed for end‐to‐end measurements of the 40m long tape based on a 1.05μm thick and 3.6mm wide YBCO film. This implies that a critical current of 235A per cm‐width is achieved by just a 1 μm thick YBCO layer. Analysis of the influence of local defects onto the integral U(I) curves allowed to formulate a general criterion for the homogeneity in terms of reduced number of tape parameters.A deterioration of tapes induced by mechanical torsion starts at a very high deformation degree: irreversibility threshold corresponds to 3000 angular degrees per meter for 4mm wide coated tape loaded with a 40N tensile axial force.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"178 1","pages":"713-719"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192414","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59399124","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}
B. Ma, U. Balachandran, Yongli Xu, R. Bhattacharya
Inclined substrate deposition (ISD) is an effective method for rapid fabrication of high‐quality template layers for YBCO‐coated conductors. We have deposited biaxially textured ISD‐MgO films on flexible metallic tapes in a reel‐to‐reel system by electron‐beam evaporation at rapid deposition rates, 2–10 nm⋅s−1. Strontium ruthenium oxide (SRO) buffer and YBCO films were grown by pulsed laser deposition (PLD). Pole figure analysis of a meter‐long ISD‐MgO tape was carried out by X‐ray diffraction using a Bruker’s D8 DISCOVER equipped with GADDS (general area detection diffraction system). The c‐axis of the ISD‐MgO film was tilted away from substrate normal. A full‐width at half maximum (FWHM) of ≈10° was observed from the φ‐scan of the MgO (002) diffraction measured on samples deposited with 35° inclination angle. Surface morphology measured by atomic force microscopy revealed a roof‐tile shaped structure for the ISD‐MgO films. Through the use of the SRO buffer, biaxial alignment in the YBCO film deposited o...
{"title":"Fabrication and Characterization of YBCO Coated Conductors by Inclined Substrate Deposition","authors":"B. Ma, U. Balachandran, Yongli Xu, R. Bhattacharya","doi":"10.1063/1.2192418","DOIUrl":"https://doi.org/10.1063/1.2192418","url":null,"abstract":"Inclined substrate deposition (ISD) is an effective method for rapid fabrication of high‐quality template layers for YBCO‐coated conductors. We have deposited biaxially textured ISD‐MgO films on flexible metallic tapes in a reel‐to‐reel system by electron‐beam evaporation at rapid deposition rates, 2–10 nm⋅s−1. Strontium ruthenium oxide (SRO) buffer and YBCO films were grown by pulsed laser deposition (PLD). Pole figure analysis of a meter‐long ISD‐MgO tape was carried out by X‐ray diffraction using a Bruker’s D8 DISCOVER equipped with GADDS (general area detection diffraction system). The c‐axis of the ISD‐MgO film was tilted away from substrate normal. A full‐width at half maximum (FWHM) of ≈10° was observed from the φ‐scan of the MgO (002) diffraction measured on samples deposited with 35° inclination angle. Surface morphology measured by atomic force microscopy revealed a roof‐tile shaped structure for the ISD‐MgO films. Through the use of the SRO buffer, biaxial alignment in the YBCO film deposited o...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"743-750"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192418","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59399245","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}
E. Ito, Y. Komano, K. Sawa, M. Murakami, N. Sakai, I. Hirabayashi
In development of a flywheel energy storage system, electric power loss reduction is expected by using superconducting bearings. However, for realization of superconducting bearing strong levitation force, rotation loss reduction and axial descent reduction are required. It is known with axial descent reduction technology that a preload method is effective, whereas by this method, the levitation force becomes quite small compared with the normal levitation. We confirmed the performance of the preload method by experiment using a YBCO superconducting electromagnet. The preload method is improved and a method, which does not change the rate of the force relaxation and makes the levitation force larger than the existing preload method is proposed.
{"title":"The Force Relaxation in Levitating High Tc Superconductor","authors":"E. Ito, Y. Komano, K. Sawa, M. Murakami, N. Sakai, I. Hirabayashi","doi":"10.1063/1.2192429","DOIUrl":"https://doi.org/10.1063/1.2192429","url":null,"abstract":"In development of a flywheel energy storage system, electric power loss reduction is expected by using superconducting bearings. However, for realization of superconducting bearing strong levitation force, rotation loss reduction and axial descent reduction are required. It is known with axial descent reduction technology that a preload method is effective, whereas by this method, the levitation force becomes quite small compared with the normal levitation. We confirmed the performance of the preload method by experiment using a YBCO superconducting electromagnet. The preload method is improved and a method, which does not change the rate of the force relaxation and makes the levitation force larger than the existing preload method is proposed.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":"824 1","pages":"820-827"},"PeriodicalIF":0.0,"publicationDate":"2006-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2192429","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59399870","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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