Shigehumi Nishio, T. Iwakami, R. Shirakashi, M. Mita
The micro-miniature JT cooler is a promising cooling device as an element of the micro-thermal system for semiconductor devices, which dissipate an incredible amount of heat. In particular, the thermal management of laser diodes is a serious problem because they require a large amount of power but must maintain a fixed temperature. Considering such a situation, the performance of a micro-miniature JT cooler was calculated under the assumption of a countercurrent heat exchanger operating with a laminar gas flow, and the guidelines of a micro-miniature JT cooler for optimizing pump power and size were designed from the viewpoint of minimizing the cost. The authors present the results in this paper. A micro-miniature JT cooler was fabricated from Si wafer using a photolithographic process, which is available for operation with C2H6 from 3 MPa to 0.1 MPa. It is shown that a cooling power of 2.1 W was obtained at 239 K with a mass flow of 51.7 mg/s.
{"title":"Study of a Micro-miniature JT Cooler","authors":"Shigehumi Nishio, T. Iwakami, R. Shirakashi, M. Mita","doi":"10.2221/JCSJ.38.680","DOIUrl":"https://doi.org/10.2221/JCSJ.38.680","url":null,"abstract":"The micro-miniature JT cooler is a promising cooling device as an element of the micro-thermal system for semiconductor devices, which dissipate an incredible amount of heat. In particular, the thermal management of laser diodes is a serious problem because they require a large amount of power but must maintain a fixed temperature. Considering such a situation, the performance of a micro-miniature JT cooler was calculated under the assumption of a countercurrent heat exchanger operating with a laminar gas flow, and the guidelines of a micro-miniature JT cooler for optimizing pump power and size were designed from the viewpoint of minimizing the cost. The authors present the results in this paper. A micro-miniature JT cooler was fabricated from Si wafer using a photolithographic process, which is available for operation with C2H6 from 3 MPa to 0.1 MPa. It is shown that a cooling power of 2.1 W was obtained at 239 K with a mass flow of 51.7 mg/s.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130077792","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 order to investigate fatigue strength and fracture mechanisms of Cu-Nb composite multistrand wires, fatigue tests at room temperature and fractographic observations were carried out using Cu-20, -30, and -40wt%Nb composite wires fabricated by in-situ processing. Fatigue strength in the high cycle region increases significantly as the content of Nb increases, as in the case of U.T.S., while the strength in the low cycle fatigue region is the lowest in Cu-30wt%Nb wire, as in the case of 0.2% proof stress. Fractographic observations revealed that slip plane decohesion facets and inclusions within the Cu wire sheath were possible sites for the crack initiation. Evidence on the roles of the Nb filaments and Cu-Nb filaments acting as barriers against crack propagation was obtained by observations of the longitudinal section of fatigued specimens.
{"title":"in-situ法Cu-Nb多芯線材の室温における疲労強度","authors":"一宗 片桐, 君幸 佐々木, 巧 伊藤, 孝一 笠場, 良孝 正路, 隆 斉藤, 謙次 後藤, 広 富士","doi":"10.2221/JCSJ.38.159","DOIUrl":"https://doi.org/10.2221/JCSJ.38.159","url":null,"abstract":"In order to investigate fatigue strength and fracture mechanisms of Cu-Nb composite multistrand wires, fatigue tests at room temperature and fractographic observations were carried out using Cu-20, -30, and -40wt%Nb composite wires fabricated by in-situ processing. Fatigue strength in the high cycle region increases significantly as the content of Nb increases, as in the case of U.T.S., while the strength in the low cycle fatigue region is the lowest in Cu-30wt%Nb wire, as in the case of 0.2% proof stress. Fractographic observations revealed that slip plane decohesion facets and inclusions within the Cu wire sheath were possible sites for the crack initiation. Evidence on the roles of the Nb filaments and Cu-Nb filaments acting as barriers against crack propagation was obtained by observations of the longitudinal section of fatigued specimens.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130585476","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":"RAg (R=Pr, Er, Ho)磁性蓄冷材料を用いたGM-冷凍機の冷凍能力","authors":"渉 八木, 水谷 宇一郎","doi":"10.2221/JCSJ.38.62","DOIUrl":"https://doi.org/10.2221/JCSJ.38.62","url":null,"abstract":"","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133533361","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}
We performed tensile tests at low temperatures from room temperature to 4 K for SUS 304L and SUS 316L in order to obtain basic data on the mechanical properties of materials to be used in a liquid hydrogen tank service. First we studied tensile curves and specimen heating during tensile testing from 70 K to 4 K, and then evaluated the ferrite contents of those alloys during tensile deformation from room temperature to 4 K. For both SUS 304L and SUS 316L, tensile strength showed a small peak around 10 K, and specimen heating decreased above 30 K as the environment temperature increased. Below 77 K, there was almost no clear influence of testing temperature on strain-induced martensitic transformation. However, for SUS 304L, the amount of ferrite content increased as the temperature decreased down to 233 K, and increased only slightly below 233 K. For SUS 316L, it increased as the temperature decreased down to 4 K, and increased steeply after 60% plastic strain above 243 K.
{"title":"Load-displacement Curves, Specimen Heating, and Strain-induced Martensitic Transformation of Austenitic Stainless Steels at Cryogenic Temperatures","authors":"T. Ogata, T. Yuri, Y. Ono","doi":"10.2221/JCSJ.42.10","DOIUrl":"https://doi.org/10.2221/JCSJ.42.10","url":null,"abstract":"We performed tensile tests at low temperatures from room temperature to 4 K for SUS 304L and SUS 316L in order to obtain basic data on the mechanical properties of materials to be used in a liquid hydrogen tank service. First we studied tensile curves and specimen heating during tensile testing from 70 K to 4 K, and then evaluated the ferrite contents of those alloys during tensile deformation from room temperature to 4 K. For both SUS 304L and SUS 316L, tensile strength showed a small peak around 10 K, and specimen heating decreased above 30 K as the environment temperature increased. Below 77 K, there was almost no clear influence of testing temperature on strain-induced martensitic transformation. However, for SUS 304L, the amount of ferrite content increased as the temperature decreased down to 233 K, and increased only slightly below 233 K. For SUS 316L, it increased as the temperature decreased down to 4 K, and increased steeply after 60% plastic strain above 243 K.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125103458","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 characteristic features of film boiling in both sub-cooled and saturated He II were experimentally investigated. Special emphasis was placed on the film boiling state around the lambda pressure (pλ= 5.04 kPa). It was found that there are two film-boiling modes clearly divided by a line just above pλ. One is a typical sub-cooled boiling mode that is normally found at higher pressures than pλ. The other mode resembles noisy film boiling in saturated He II. The boundary between the two boiling modes lies at the pressure just above pλ, the pressure of which slightly increases as the bath temperature decreases. It was found that noisy film boiling does not occur and the regions of the sub-cooled and silent film boiling modes connect directly in the vicinity of the lambda point. At the same time, the pressure and temperature variation were also measured and the cause of the occurrence of those variations was clarified. The features of each boiling mode were characterized.
{"title":"Variation of the film boiling mode in He II from the vicinity of the lambda pressure down to the saturated state","authors":"M. Nozawa, M. Murakami, Peng Zhang, N. Kimura","doi":"10.2221/JCSJ.39.277","DOIUrl":"https://doi.org/10.2221/JCSJ.39.277","url":null,"abstract":"The characteristic features of film boiling in both sub-cooled and saturated He II were experimentally investigated. Special emphasis was placed on the film boiling state around the lambda pressure (pλ= 5.04 kPa). It was found that there are two film-boiling modes clearly divided by a line just above pλ. One is a typical sub-cooled boiling mode that is normally found at higher pressures than pλ. The other mode resembles noisy film boiling in saturated He II. The boundary between the two boiling modes lies at the pressure just above pλ, the pressure of which slightly increases as the bath temperature decreases. It was found that noisy film boiling does not occur and the regions of the sub-cooled and silent film boiling modes connect directly in the vicinity of the lambda point. At the same time, the pressure and temperature variation were also measured and the cause of the occurrence of those variations was clarified. The features of each boiling mode were characterized.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"439 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123272400","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}
Synopsis: The fundamentals of thermoacoustics constitute understanding thermoacoustic phenomena, the proposal of new thermoacoustic devices, and the development of new experimental techniques. This paper describes a practical guide to measurements of important physical quantities in thermoacoustic systems to help beginners understand the basic techniques. The direct method, involving measurements of pressure and velocity oscillations, and the two-sensor method are introduced for the measurement of work flow. A method for the dynamic calibration of a thermocouple is also presented to make measurements of temperature fluctuation possible. Particular emphasis is given accurately determining the phasing between oscillatory quantities.
{"title":"Beginner's Guide to Measurement Techniques in Thermoacoustic Systems","authors":"T. Biwa","doi":"10.2221/JCSJ.43.517","DOIUrl":"https://doi.org/10.2221/JCSJ.43.517","url":null,"abstract":"Synopsis: The fundamentals of thermoacoustics constitute understanding thermoacoustic phenomena, the proposal of new thermoacoustic devices, and the development of new experimental techniques. This paper describes a practical guide to measurements of important physical quantities in thermoacoustic systems to help beginners understand the basic techniques. The direct method, involving measurements of pressure and velocity oscillations, and the two-sensor method are introduced for the measurement of work flow. A method for the dynamic calibration of a thermocouple is also presented to make measurements of temperature fluctuation possible. Particular emphasis is given accurately determining the phasing between oscillatory quantities.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123592970","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}
Magnetic beads are widely used for biotechnology and medical fields because they can be easily manipulated byexternal magnetic field. Recently, there has been a great increase in the number of papers taking an exponential approach tobiomedical applications of the magnetic beads. We outline the latest trend of domestic researches of the magnetic beads appliedto biomedical investigation
{"title":"Biomedical Applications of Magnetic Beads","authors":"T. Nakagawa, S. Seino, T. Yamamoto, M. Abe","doi":"10.2221/JCSJ.45.436","DOIUrl":"https://doi.org/10.2221/JCSJ.45.436","url":null,"abstract":"Magnetic beads are widely used for biotechnology and medical fields because they can be easily manipulated byexternal magnetic field. Recently, there has been a great increase in the number of papers taking an exponential approach tobiomedical applications of the magnetic beads. We outline the latest trend of domestic researches of the magnetic beads appliedto biomedical investigation","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126949077","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}
Keeping HIP treatment in mind, diffusion bonding conditions of 316L-type austenitic steels for a low-temperature damper were investigated. It was found that diffusion bonding of 316L with high-content nitrogen onto 316L with high-content nitrogen was difficult. It was tentatively concluded that the martensite formation near the bonding surface induced during the cooling process was most likely responsible for reducing the bonding strength at -196°C. Complete diffusion bonding properties at -196°C were attained by adopting a combination of 316L with high-content nitrogen and 316L with low-content nitrogen under the following bonding conditions: nitrogen content less than 0.017% in 316L with low-content nitrogen, bonding temperature above 1039°C, surface roughness below 0.07 μm, pressure above 130 MPa and pressing time above 4 h.
{"title":"Influence of Bonding Conditions and Nitrogen Content on Diffusion Bonding of 316L-type Austenitic Steels: Diffusion Bonding for Low-temperature Dampers of Superconducting Generators","authors":"Takanobu Mori, Hiroshi Sato","doi":"10.2221/JCSJ.43.42","DOIUrl":"https://doi.org/10.2221/JCSJ.43.42","url":null,"abstract":"Keeping HIP treatment in mind, diffusion bonding conditions of 316L-type austenitic steels for a low-temperature damper were investigated. It was found that diffusion bonding of 316L with high-content nitrogen onto 316L with high-content nitrogen was difficult. It was tentatively concluded that the martensite formation near the bonding surface induced during the cooling process was most likely responsible for reducing the bonding strength at -196°C. Complete diffusion bonding properties at -196°C were attained by adopting a combination of 316L with high-content nitrogen and 316L with low-content nitrogen under the following bonding conditions: nitrogen content less than 0.017% in 316L with low-content nitrogen, bonding temperature above 1039°C, surface roughness below 0.07 μm, pressure above 130 MPa and pressing time above 4 h.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126961093","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}
To clarify the Jc-compressive strain properties of Nb3Sn superconducting wires fabricated using the internal-tin process, an evaluation of the properties has been carried out by applying pre-compressive strain to the wires. The strain was induced by clothing the wires in stainless steel that has large thermal contraction and then subjecting the wires to a heat-treatment process. We succeeded in shifting the peak strain from 0.3% to 0.7- 0.8% and grasping the Jc-compressive strain properties. These experimental values agree well with the stress analysis results. We also examined the differences in Jc-strain properties including the compressive strain between internal-tin processed wires and bronze wires. As a result, it was found that Jc-strain properties are different between them; however when both wires are clothed in stainless steel, they show almost the similar strain-sensitivity. Using these data, the specification value on Jc for the strand wire of the ITER TF coils was examined. It was concluded that 9.7% higher Jc is needed for internal-tin processed wires as compared to bronze route Nb3Sn wires at T=4.2 K and B=12 T, assuming that both wires have the same Jc at T=6 K and B=11.8T.
{"title":"Evaluation of Jc-compressive Strain Properties for Nb3Sn Wires","authors":"Y. Kubo, Hideji Naitoh, M. Hasegawa","doi":"10.2221/JCSJ.39.399","DOIUrl":"https://doi.org/10.2221/JCSJ.39.399","url":null,"abstract":"To clarify the Jc-compressive strain properties of Nb3Sn superconducting wires fabricated using the internal-tin process, an evaluation of the properties has been carried out by applying pre-compressive strain to the wires. The strain was induced by clothing the wires in stainless steel that has large thermal contraction and then subjecting the wires to a heat-treatment process. We succeeded in shifting the peak strain from 0.3% to 0.7- 0.8% and grasping the Jc-compressive strain properties. These experimental values agree well with the stress analysis results. We also examined the differences in Jc-strain properties including the compressive strain between internal-tin processed wires and bronze wires. As a result, it was found that Jc-strain properties are different between them; however when both wires are clothed in stainless steel, they show almost the similar strain-sensitivity. Using these data, the specification value on Jc for the strand wire of the ITER TF coils was examined. It was concluded that 9.7% higher Jc is needed for internal-tin processed wires as compared to bronze route Nb3Sn wires at T=4.2 K and B=12 T, assuming that both wires have the same Jc at T=6 K and B=11.8T.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115048103","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}
J. Suzuki, K. Kadowaki, Y. Hata, S. Okayasu, T. Nishio, I. Kakeya, A. Odawara, A. Nagata, S. Nakayama, K. Chinone
Recently, vortices confined into micro-scale superconductors with shapes like a disk, triangle, square, etc., have attracted much attention because of the quantum phase transition of the self-organized vortex arrangement occurring within such geometrical constraints. Such a transition can be observed using a scanning SQUID microscope with high spatial resolution. We have successfully improved spatial resolution by incorporating a microfabrication technique that reduces both the size of the pick-up coil of the micro DC-SQUID and the standoff distance between the pick-up coil and the sample surface. Using this microscope, we have studied vortex arrangements in micro-scale superconductors made of Nb and YBa2Cu3O7−δ films with various sizes and geometrical shapes. A peculiar oscillating behavior of diamagnetic magnetization corresponding to the particular vortex state was observed.
{"title":"Scanning SQUID Microscopy for Magnetic Flux Systems","authors":"J. Suzuki, K. Kadowaki, Y. Hata, S. Okayasu, T. Nishio, I. Kakeya, A. Odawara, A. Nagata, S. Nakayama, K. Chinone","doi":"10.2221/JCSJ.38.485","DOIUrl":"https://doi.org/10.2221/JCSJ.38.485","url":null,"abstract":"Recently, vortices confined into micro-scale superconductors with shapes like a disk, triangle, square, etc., have attracted much attention because of the quantum phase transition of the self-organized vortex arrangement occurring within such geometrical constraints. Such a transition can be observed using a scanning SQUID microscope with high spatial resolution. We have successfully improved spatial resolution by incorporating a microfabrication technique that reduces both the size of the pick-up coil of the micro DC-SQUID and the standoff distance between the pick-up coil and the sample surface. Using this microscope, we have studied vortex arrangements in micro-scale superconductors made of Nb and YBa2Cu3O7−δ films with various sizes and geometrical shapes. A peculiar oscillating behavior of diamagnetic magnetization corresponding to the particular vortex state was observed.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116443826","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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