We fabricated 2.1GHz TM010-mode microwave resonators with (Bi, Pb)2Sr2Ca2Cu3Ox (Bi2223) superconducting thick films on a Ba(Sn, Mg, Ta)O3 dielectric disk with a relative dielectric constant of er=24. The Bi2223 thick films were screen-printed on both sides of the dielectric disk and subjected to a double repetition of cold isostatic pressing at 0.4GPa and sintering at various temperatures ranging from 820 to 840°C. An increase of the sintering temperature raises the Bi2223 phase purity up to 98% on the surfaces of the thick films, but high-temperature sintering above 830°C causes a chemical reaction at the interface between the Bi2223 thick film and the dielectric disk. An optimization of the sintering temperature to 830°C gives the unloaded quality factors Qu as much as 74, 000 at 70K and 158, 000 at 25K, which correspond to surface resistances Rs of 0.34 and 0.15mΩ for Bi2223 thick films, respectively. These values are approximately 20 times higher than those for the resonator using Ag electrodes with the same structure.
{"title":"Microwave Properties of Bi2223 Thick Films on Ba(Sn, Mg, Ta)O3 Dielectric Disk","authors":"A. Oota, Daiki Washimoto, N. Kato, Y. Kintaka","doi":"10.2221/JCSJ.37.157","DOIUrl":"https://doi.org/10.2221/JCSJ.37.157","url":null,"abstract":"We fabricated 2.1GHz TM010-mode microwave resonators with (Bi, Pb)2Sr2Ca2Cu3Ox (Bi2223) superconducting thick films on a Ba(Sn, Mg, Ta)O3 dielectric disk with a relative dielectric constant of er=24. The Bi2223 thick films were screen-printed on both sides of the dielectric disk and subjected to a double repetition of cold isostatic pressing at 0.4GPa and sintering at various temperatures ranging from 820 to 840°C. An increase of the sintering temperature raises the Bi2223 phase purity up to 98% on the surfaces of the thick films, but high-temperature sintering above 830°C causes a chemical reaction at the interface between the Bi2223 thick film and the dielectric disk. An optimization of the sintering temperature to 830°C gives the unloaded quality factors Qu as much as 74, 000 at 70K and 158, 000 at 25K, which correspond to surface resistances Rs of 0.34 and 0.15mΩ for Bi2223 thick films, respectively. These values are approximately 20 times higher than those for the resonator using Ag electrodes with the same structure.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"157-161"},"PeriodicalIF":0.0,"publicationDate":"2002-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186985","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}
Although the thermoacoustic theory of the 20th century has succeeded in making a variety of thermoacoustic phenomena understood and contributed to the development of thermoacoustic devices, the application is shown to be limited to the ideal gas of the first kind; if the theory is applied to nonideal gas, the result violates the first and the second laws of thermodynamics in some limiting cases. A consideration of the postulated relationship between the entropy flow and the oscillating entropy leads to a proposal of a new relationship, which is an extension of the old relationship to general fluid, of which thermal expansion coefficient is not equal to the inverse of temperature. The new relationship modifies expressions of both progressive and standing wave components of the heat flow. Some effects of the extension on the explanation of refrigeration power at low temperatures are discussed. Also discussed is the possibility of thermoacoustic heat engine with the working fluid of a negative thermal expansion coefficient.
{"title":"An Extension of the Thermoacoustic Theory","authors":"A. Tominaga","doi":"10.2221/JCSJ.37.162","DOIUrl":"https://doi.org/10.2221/JCSJ.37.162","url":null,"abstract":"Although the thermoacoustic theory of the 20th century has succeeded in making a variety of thermoacoustic phenomena understood and contributed to the development of thermoacoustic devices, the application is shown to be limited to the ideal gas of the first kind; if the theory is applied to nonideal gas, the result violates the first and the second laws of thermodynamics in some limiting cases. A consideration of the postulated relationship between the entropy flow and the oscillating entropy leads to a proposal of a new relationship, which is an extension of the old relationship to general fluid, of which thermal expansion coefficient is not equal to the inverse of temperature. The new relationship modifies expressions of both progressive and standing wave components of the heat flow. Some effects of the extension on the explanation of refrigeration power at low temperatures are discussed. Also discussed is the possibility of thermoacoustic heat engine with the working fluid of a negative thermal expansion coefficient.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"162-167"},"PeriodicalIF":0.0,"publicationDate":"2002-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186992","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}
T. Yamanaka, T. Nakano, K. Ueshiro, T. Okawa, K. Tsutsumi, S. Nagaya, N. Hirano, S. Koso
The investigation of the possibility of low-cost SMES is an indispensable theme if that practical use is to be realized. We optimized the system composition by selecting the most suitable charge/discharge rate. We conducted the optimum design on the structure of superconductor and the coil system under special consideration of the material unit price, the total material amount, the manufacturing efficiency, and so on. The pool-cooling double-row solenoid system using NbTi base conductor is the most suitable one as 15kWh-100MW SMES for the system-stabilizing use and 500kWh-100MW SMES for the load-fluctuation-compensating and frequency-controlling use.
{"title":"Cost Cut Design of SMES","authors":"T. Yamanaka, T. Nakano, K. Ueshiro, T. Okawa, K. Tsutsumi, S. Nagaya, N. Hirano, S. Koso","doi":"10.2221/JCSJ.37.122","DOIUrl":"https://doi.org/10.2221/JCSJ.37.122","url":null,"abstract":"The investigation of the possibility of low-cost SMES is an indispensable theme if that practical use is to be realized. We optimized the system composition by selecting the most suitable charge/discharge rate. We conducted the optimum design on the structure of superconductor and the coil system under special consideration of the material unit price, the total material amount, the manufacturing efficiency, and so on. The pool-cooling double-row solenoid system using NbTi base conductor is the most suitable one as 15kWh-100MW SMES for the system-stabilizing use and 500kWh-100MW SMES for the load-fluctuation-compensating and frequency-controlling use.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"122-129"},"PeriodicalIF":0.0,"publicationDate":"2002-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187218","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}
K. Asano, K. Takeuchi, K. Tsutsumi, S. Nagaya, N. Hirano, S. Kouso
Superconducting magnetic energy storage (SMES) is a promising technology for electric utility stabilization of transmission, load compensation, and frequency regulation. This paper presents the results of a study to reduce the capital cost of an SMES system. The study focused on a toroidal-shaped superconducting coil system and concerned both 100MW/15kWh SMES for stabilization on transmission and 100MW/500kWh SMES for load compensation and frequency regulation. The charge/discharge ratio (k) was optimized in consideration of the economical efficiency of the whole SMES system, and thereby k=0.52 for small-scale SMES and k=0.86 for medium-scale SMES were obtained. To reduce the cost of a superconducting coil system, the system's design should be based on the concepts of a compact, a simple structure and small material amount. The aspect ratio of a toroidal coil system and that of a solenoid unit coil are determined from the viewpoints of minimum material amount. Aluminum-stabilized forced-flow superconductors have been newly proposed to achieve high voltage and high magnetic-field design in correspondence with small coils and reduced coil-turn numbers. New oxidization techniques for the aluminum surface of the stabilizer have been developed and the structure of the superconductor is designed simply and symmetrically to reduce manufacturing cost and ac loss. The supercondutor's favorable performances have been confirmed through short sample tests. These results provide a strong incentive for utilities to encourage and support the development of SMES cost-reduction technology.
{"title":"A Study of Cost Reduction on the SMES System","authors":"K. Asano, K. Takeuchi, K. Tsutsumi, S. Nagaya, N. Hirano, S. Kouso","doi":"10.2221/JCSJ.37.106","DOIUrl":"https://doi.org/10.2221/JCSJ.37.106","url":null,"abstract":"Superconducting magnetic energy storage (SMES) is a promising technology for electric utility stabilization of transmission, load compensation, and frequency regulation. This paper presents the results of a study to reduce the capital cost of an SMES system. The study focused on a toroidal-shaped superconducting coil system and concerned both 100MW/15kWh SMES for stabilization on transmission and 100MW/500kWh SMES for load compensation and frequency regulation. The charge/discharge ratio (k) was optimized in consideration of the economical efficiency of the whole SMES system, and thereby k=0.52 for small-scale SMES and k=0.86 for medium-scale SMES were obtained. To reduce the cost of a superconducting coil system, the system's design should be based on the concepts of a compact, a simple structure and small material amount. The aspect ratio of a toroidal coil system and that of a solenoid unit coil are determined from the viewpoints of minimum material amount. Aluminum-stabilized forced-flow superconductors have been newly proposed to achieve high voltage and high magnetic-field design in correspondence with small coils and reduced coil-turn numbers. New oxidization techniques for the aluminum surface of the stabilizer have been developed and the structure of the superconductor is designed simply and symmetrically to reduce manufacturing cost and ac loss. The supercondutor's favorable performances have been confirmed through short sample tests. These results provide a strong incentive for utilities to encourage and support the development of SMES cost-reduction technology.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"106-113"},"PeriodicalIF":0.0,"publicationDate":"2002-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186891","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}
S. Hanai, M. Shimada, Kazuhiko Shimada, S. Kouso, K. Tsutsumi, S. Nagaya
{"title":"A Proposal of a Cost-reduced SMES System","authors":"S. Hanai, M. Shimada, Kazuhiko Shimada, S. Kouso, K. Tsutsumi, S. Nagaya","doi":"10.2221/JCSJ.37.114","DOIUrl":"https://doi.org/10.2221/JCSJ.37.114","url":null,"abstract":"","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"114-121"},"PeriodicalIF":0.0,"publicationDate":"2002-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186900","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. Tsuda, K. Egawa, R. Saito, T. Takayanagi, S. Nagaya, K. Tsutsumi
A cost-reduction design of the SMES system is proposed, using Nb3Sn conductors that in recent years have shown progress in cost and performance. The main feature of this design should be a combination of Nb3Sn single-strand conductors and a small bore solenoid (=CELL) coil. The cost reduction was intended to use mass production methods and to operate small or medium-sized factories. However, this simple and compact design brings up new issues. Quench protection is especially a key issue. It needs high-speed quench detection and forced-quench that will reduce the unbalance magnetic force at quench and prevent the CELL coil from burning up. This cost-reduction design of the SMES system using Nb3Sn conductors is sufficiently competitive with the other designs that use NbTi conductors.
{"title":"Study on Cost Reduction of SMES System, Using Nb3Sn Conductor","authors":"Y. Tsuda, K. Egawa, R. Saito, T. Takayanagi, S. Nagaya, K. Tsutsumi","doi":"10.2221/JCSJ.37.130","DOIUrl":"https://doi.org/10.2221/JCSJ.37.130","url":null,"abstract":"A cost-reduction design of the SMES system is proposed, using Nb3Sn conductors that in recent years have shown progress in cost and performance. The main feature of this design should be a combination of Nb3Sn single-strand conductors and a small bore solenoid (=CELL) coil. The cost reduction was intended to use mass production methods and to operate small or medium-sized factories. However, this simple and compact design brings up new issues. Quench protection is especially a key issue. It needs high-speed quench detection and forced-quench that will reduce the unbalance magnetic force at quench and prevent the CELL coil from burning up. This cost-reduction design of the SMES system using Nb3Sn conductors is sufficiently competitive with the other designs that use NbTi conductors.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"130-137"},"PeriodicalIF":0.0,"publicationDate":"2002-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187237","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}
MRI systems in the medical field are widely used, and it is already well known that great progress has been made in the development of superconducting technologies. Superconducting magnets are also being used for growing high-quality silicon single crystals. This is one example of the industrial application of superconductivity, illustrating that superconducting technologies have been able to meet many customer requirements. In this report, we present the history of the technological developments for these industrial applications of superconducting magnets.
{"title":"Development of the Industrial Application of Superconducting Magnet","authors":"H. Takano, H. Ogiwara","doi":"10.2221/JCSJ.37.40","DOIUrl":"https://doi.org/10.2221/JCSJ.37.40","url":null,"abstract":"MRI systems in the medical field are widely used, and it is already well known that great progress has been made in the development of superconducting technologies. Superconducting magnets are also being used for growing high-quality silicon single crystals. This is one example of the industrial application of superconductivity, illustrating that superconducting technologies have been able to meet many customer requirements. In this report, we present the history of the technological developments for these industrial applications of superconducting magnets.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"40-47"},"PeriodicalIF":0.0,"publicationDate":"2002-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187488","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}
In appreciation of a time relaxation behavior of critical currents as a result of flux creep in type-II superconductors, the possibility has been investigated that superconducting magnets may quench even in the persistent current mode. Because the time relaxation behavior of critical currents has been not observed directly, it has been thought as “the shadow, ” i.e., an implicit phenomenon. If a quench in the persistent current mode is experimentally confirmed, “the substance” of the time-dependent critical current will be grasped and then it appears explicitly. Experimental methods that can meet with quenches in the persistent current mode are proposed.
{"title":"Possibility of Quench of Superconducting Magnets in the Persistent Current Mode","authors":"K. Kuroda","doi":"10.2221/JCSJ.37.48","DOIUrl":"https://doi.org/10.2221/JCSJ.37.48","url":null,"abstract":"In appreciation of a time relaxation behavior of critical currents as a result of flux creep in type-II superconductors, the possibility has been investigated that superconducting magnets may quench even in the persistent current mode. Because the time relaxation behavior of critical currents has been not observed directly, it has been thought as “the shadow, ” i.e., an implicit phenomenon. If a quench in the persistent current mode is experimentally confirmed, “the substance” of the time-dependent critical current will be grasped and then it appears explicitly. Experimental methods that can meet with quenches in the persistent current mode are proposed.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"48-53"},"PeriodicalIF":0.0,"publicationDate":"2002-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187712","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 paper describes the development of a conductive-cooled superconducting magnet that uses no cryogen, such as liquid helium or liquid nitrogen. First, the history of the development is introduced. A conductive-cooled superconducting magnet was realized in the late 1980s for the first time and was commercialized about 10 years ago. The technical points and construction for the magnet are explained. The important points were a 4K-GM cryocooler and an HTS superconducting current lead. A conventional GM cryocooler had not achieved 4K level, but by using magnetic regenerator material, we realized refrigeration at liquid helium temperature. An HTS current lead was used as a current lead between a thermal shield and a superconducting coil. Heat leakage by a superconducting current lead is less than 1/10th by a conventional copper current lead. Heat leakage to the 4K level was then dramatically reduced, and the total thermal load at 4K level becomes low enough for a 4K-GM cryocooler. In a conductive-cooled superconducting magnet, a superconducting coil is directly cooled by the second stage of a 4K-GM cryocooler at the 4K level via a good thermal conductive pass. The coil is surrounded by a thermal shield, which is cooled by the first cooling stage at around 50K. A conductive-cooled superconducting magnet has such features as simple operation, small size, and easy access to a magnetic field. Several companies have commercialized a conductive-cooled magnet, and the magnets have been applied not only to research, but also to industrial use, such as MRI, silicon crystal growth, and magnetic separation. The latest R & D and future aspects for a conductive-cooled superconducting magnet are also described.
{"title":"Development of Conductive-cooled Superconducting Magnet","authors":"T. Kuriyama, H. Maeda, H. Ogiwara","doi":"10.2221/JCSJ.37.18","DOIUrl":"https://doi.org/10.2221/JCSJ.37.18","url":null,"abstract":"This paper describes the development of a conductive-cooled superconducting magnet that uses no cryogen, such as liquid helium or liquid nitrogen. First, the history of the development is introduced. A conductive-cooled superconducting magnet was realized in the late 1980s for the first time and was commercialized about 10 years ago. The technical points and construction for the magnet are explained. The important points were a 4K-GM cryocooler and an HTS superconducting current lead. A conventional GM cryocooler had not achieved 4K level, but by using magnetic regenerator material, we realized refrigeration at liquid helium temperature. An HTS current lead was used as a current lead between a thermal shield and a superconducting coil. Heat leakage by a superconducting current lead is less than 1/10th by a conventional copper current lead. Heat leakage to the 4K level was then dramatically reduced, and the total thermal load at 4K level becomes low enough for a 4K-GM cryocooler. In a conductive-cooled superconducting magnet, a superconducting coil is directly cooled by the second stage of a 4K-GM cryocooler at the 4K level via a good thermal conductive pass. The coil is surrounded by a thermal shield, which is cooled by the first cooling stage at around 50K. A conductive-cooled superconducting magnet has such features as simple operation, small size, and easy access to a magnetic field. Several companies have commercialized a conductive-cooled magnet, and the magnets have been applied not only to research, but also to industrial use, such as MRI, silicon crystal growth, and magnetic separation. The latest R & D and future aspects for a conductive-cooled superconducting magnet are also described.","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"37 1","pages":"18-26"},"PeriodicalIF":0.0,"publicationDate":"2002-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187035","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}
{"title":"Application of Superconducting NMR for Protein Structure Determination","authors":"H. Maeda, Yutaka Ito, S. Yokoyama","doi":"10.2221/JCSJ.37.2","DOIUrl":"https://doi.org/10.2221/JCSJ.37.2","url":null,"abstract":"","PeriodicalId":93144,"journal":{"name":"Teion kogaku = Cryogenic engineering : [official journal of the Cryogenic Association of Japan]","volume":"28 1","pages":"2-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187106","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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