The Experts below are selected from a list of 8289 Experts worldwide ranked by ideXlab platform
X F Zhang - One of the best experts on this subject based on the ideXlab platform.
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stable magnetocaloric effect and Refrigeration Capacity in co doped fecomnzrnbb amorphous ribbons near room temperature
Journal of Alloys and Compounds, 2017Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract The Fe-based amorphous alloys are promising candidates for magnetic Refrigeration due to their large magnetocaloric effect, outstanding mechanical property and high electrical resistivity. In this paper, the influence of Co addition on the magnetocaloric effect and Refrigeration Capacity has been studied for Fe 82− x Co x Mn 4 Zr 8 Nb 2 B 4 ribbons. X-ray diffraction patterns indicate that the Co-doped ribbons are amorphous. The Curie temperature can be adjusted from 271 to 363 K with the Co atomic concentration changing from 2 to 8. Favorably, both isothermal entropy change (Δ S T ) and Refrigeration Capacity ( RC ) remain nearly the same magnitude for the Co-doped ribbons. For a field change of 3 T, the maximum −Δ S T is about 1.7 J/kgK and the RC is about 115 J/kg for a temperature span of 80 K. The stable magnetocaloric effect and Refrigeration Capacity near room temperature reveals that the Co-doped amorphous ribbons may be considered as refrigerants for magnetic Refrigeration.
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enhancement of Refrigeration Capacity and table like magnetocaloric effect in la0 8ca0 2mno3 la0 8k0 2mno3 nanocrystalline composite
Ceramics International, 2015Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract In this paper we report on the magnetocaloric effect and Refrigeration Capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247 K and 281 K, respectively. The maximum values of isothermal entropy change ( − Δ S T , max ) are found to be 4.25 J/kg K and 3.71 J/kg K under a magnetic field change of 5 T for LCMO and LKMO, respectively. The composite exhibits a table-like Δ S T curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.
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Enhancement of Refrigeration Capacity and table-like magnetocaloric effect in La0.8Ca0.2MnO3/La0.8K0.2MnO3 nanocrystalline composite
Ceramics International, 2015Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract In this paper we report on the magnetocaloric effect and Refrigeration Capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247 K and 281 K, respectively. The maximum values of isothermal entropy change ( − Δ S T , max ) are found to be 4.25 J/kg K and 3.71 J/kg K under a magnetic field change of 5 T for LCMO and LKMO, respectively. The composite exhibits a table-like Δ S T curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.
G F Wang - One of the best experts on this subject based on the ideXlab platform.
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stable magnetocaloric effect and Refrigeration Capacity in co doped fecomnzrnbb amorphous ribbons near room temperature
Journal of Alloys and Compounds, 2017Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract The Fe-based amorphous alloys are promising candidates for magnetic Refrigeration due to their large magnetocaloric effect, outstanding mechanical property and high electrical resistivity. In this paper, the influence of Co addition on the magnetocaloric effect and Refrigeration Capacity has been studied for Fe 82− x Co x Mn 4 Zr 8 Nb 2 B 4 ribbons. X-ray diffraction patterns indicate that the Co-doped ribbons are amorphous. The Curie temperature can be adjusted from 271 to 363 K with the Co atomic concentration changing from 2 to 8. Favorably, both isothermal entropy change (Δ S T ) and Refrigeration Capacity ( RC ) remain nearly the same magnitude for the Co-doped ribbons. For a field change of 3 T, the maximum −Δ S T is about 1.7 J/kgK and the RC is about 115 J/kg for a temperature span of 80 K. The stable magnetocaloric effect and Refrigeration Capacity near room temperature reveals that the Co-doped amorphous ribbons may be considered as refrigerants for magnetic Refrigeration.
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enhancement of Refrigeration Capacity and table like magnetocaloric effect in la0 8ca0 2mno3 la0 8k0 2mno3 nanocrystalline composite
Ceramics International, 2015Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract In this paper we report on the magnetocaloric effect and Refrigeration Capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247 K and 281 K, respectively. The maximum values of isothermal entropy change ( − Δ S T , max ) are found to be 4.25 J/kg K and 3.71 J/kg K under a magnetic field change of 5 T for LCMO and LKMO, respectively. The composite exhibits a table-like Δ S T curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.
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Enhancement of Refrigeration Capacity and table-like magnetocaloric effect in La0.8Ca0.2MnO3/La0.8K0.2MnO3 nanocrystalline composite
Ceramics International, 2015Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract In this paper we report on the magnetocaloric effect and Refrigeration Capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247 K and 281 K, respectively. The maximum values of isothermal entropy change ( − Δ S T , max ) are found to be 4.25 J/kg K and 3.71 J/kg K under a magnetic field change of 5 T for LCMO and LKMO, respectively. The composite exhibits a table-like Δ S T curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.
Takasu Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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Optimization of Operational Parameters for A 4K-GM Refrigerator
A Cryogenic Engineering Conference Publication, 1996Co-Authors: Toru Kuriyama, Y. Ohtani, M. Takahashi, Hideki Nakagome, H. Nitta, T. Tsukagoshi, A. Yoshida, Takasu HashimotoAbstract:This paper describes the experimental results of a 4 K-GM refrigerator, which uses magnetic regenerator materials. The technical point of this study is ascertaining the effects of operational parameters for improving the 4.2 K Refrigeration Capacity. Compressor Capacity and displacer stroke are main parameters in this study. A larger compressor enables a larger Refrigeration Capacity at a smaller temperature difference in the second regenerator. A smaller compressor, however, is preferable to maintain 4.2 K, when temperature difference is large. Displacer strokes of 12, 20 and 32 mm are investigated. The optimum reciprocating speed for the 4.2 K Refrigeration Capacity strongly depends on the displacer stroke. The largest Refrigeration Capacity, however, are almost equal for each of the strokes. In this study, the optimized stroke is found to be 20 mm to obtain Refrigeration capacities at the second stage (4.2 K) and the first stage (40 K) simultaneously.
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Improvement of Two-Stage GM Refrigerator Performance Using a Hybrid Regenerator
Advances in Cryogenic Engineering Materials, 1994Co-Authors: H. Makuuchi, Takasu Hashimoto, Atsushi Onishi, Toshimi Satoh, Yoshiaki KanazawaAbstract:To improve the performance of two-stage GM refrigerators, a hybrid regenerator with magnetic materials of Er3Ni and ErNi0.9Co0.1 was used in the 2nd stage regenerator because of its large heat exchange Capacity. The largest Refrigeration Capacity achieved with the hybrid regenerator was 0.95W at helium liquefied temperature of 4.2K. This Capacity is 15.9% greater than the 0.82W refrigerator with only Er3Ni as the 2nd regenerator material. Use of the hybrid regenerator not only increases the Refrigeration Capacity at 4.2K, but also allows the 4K GM refrigerator to be used with large 1st stage Refrigeration Capacity, thus making it more practical.
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Development of 1 Watt Class 4 K Gm Refrigerator with Magnetic Regenerator Materials
Advances in Cryogenic Engineering, 1994Co-Authors: Toru Kuriyama, Hideki Nakagome, H. Nitta, Takasu Hashimoto, Takahashi Masahiko, Masanori YabukiAbstract:This paper describes the experimental results of the 4 K GM refrigerator which obtained the maximum Refrigeration Capacity of 1.05 W at 4.2 K. The COP value for the 4 K GM refrigerator at 4.3 K was 1.92*10-4 and almost same as that for commercially used GM+JT refrigerator at 4.3 K. The technical points of this refrigerator were to adopt a hybrid structural regenerator and to optimize the intake/exhaust valve timing. The hybrid structural regenerator consisted of Ero.9Ybo.1Ni and Er3Co regenerator materials. Ero.9Ybo.1Ni has a large heat Capacity at lower than 10 K. On the other hand, Er3Co has a large heat Capacity at a higher temperature region. The intake/exhaust valve timing was also changed to improve the Refrigeration Capacity at 4.2 K.
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Helium liquefaction by a two-stage Gifford-McMahon-cycle refrigerator using new regenerator material of Er3Ni
Japanese Journal of Applied Physics, 1992Co-Authors: Toru Kuriyama, Hideki Nakagome, Takahashi Masahiko, Tatsuji Eda, Hikaru Seshake, Takasu HashimotoAbstract:This paper describes the experimental results of the two-stage Gifford-McMahon (GM)-cycle refrigerator using a rare-earth compound as a regenerator material. The purpose of this study was to obtain a practical Refrigeration Capacity at 4.2 K, where the lowest temperature for a typical two-stage GM-cycle refrigerator is limited to 8 K. The technical point was to adopt erbium 3 nickel (Er3Ni) as a regenerator material. A Refrigeration Capacity of 0.28 W at 4.2 K was obtained, and the lowest temperature of 3.22 K was achieved. Helium liquefaction by the two-stage GM-cycle refrigerator was also confirmed for the first time.
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Analysis of Rare Earth Compound Regenerators Operating at 4 K
Advances in Cryogenic Engineering, 1992Co-Authors: Hikaru Seshake, Toru Kuriyama, Takasu Hashimoto, Tatsuji Eda, K. Matsumoto, Hideki NakagomeAbstract:This paper describes the analysis of regenerators which consist of rare earth compounds. In a regenerative cycle refrigerator, Refrigeration loss is larger than useful Refrigeration Capacity at liquid helium temperature, and the main loss is regenerator loss. The purpose of this paper is to establish a numerical calculation method which gives useful information for designing high efficiency regenerators. The model regenerator consisted of two regenerator compounds: Er3Ni, which is hot-side material, and another material such as ErNi2, Er0.75Dy0.25Ni2, ErNi, or Er0.9Yb0.1Ni. The regenerator efficiency was calculated for various ratios of the two materials. Regenerator efficiencies for various combinations of rare earth compounds are systematically discussed. The maximum regenerator efficiency was obtained at 4 K with the condition that Er3Ni was 45% and Er0.9Yb0.1Ni was 55% of the regenerator volume. Moreover, it was shown that a refrigerator with this optimized regenerator could achieve a 52% larger Refrigeration Capacity than one with an all-Er3Ni regenerator.
Hideki Nakagome - One of the best experts on this subject based on the ideXlab platform.
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Analysis of a High Efficiency 4K GM Refrigerator Operating at a Lower Pressure Ratio
Cryocoolers 10, 2002Co-Authors: T. Usami, Y. Ohtani, Tetsuji Okamura, Shigeharu Kabashima, Hideo Hatakeyama, Hideki NakagomeAbstract:Recently, regenerative refrigerators such as Gifford-McMahon (GM) refrigerators have achieved liquid helium temperature levels using magnetic regenerator materials that have a much larger specific heat Capacity below 10K than conventional second regenerator materials of lead. In this investigation a high efficiency 4K GM refrigerator using magnetic regenerator materials was developed and investigated. A Refrigeration Capacity of 2.04W at 4.2K was obtained for 3.4 kW of compressor input power by optimization of the operating pressure ratio. A maximum coefficient of performance (COP) of 6.04 × 10 −4 was achieved at 4.2K at a pressure ratio of 2.43 and an operating frequency of 30 rpm. In the investigation the refrigerator was operated at various pressure ratios, and at each pressure ratio measurements were made of compressor work, of pressure-volume (P-V) characteristics of the second expansion volume, and of Refrigeration Capacity at 4.2K. Refrigeration losses were estimated at 4.2K using the experimental results and are discussed. Operating frequency was also optimized to maximize second stage Refrigeration performance.
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Optimization of Operational Parameters for A 4K-GM Refrigerator
A Cryogenic Engineering Conference Publication, 1996Co-Authors: Toru Kuriyama, Y. Ohtani, M. Takahashi, Hideki Nakagome, H. Nitta, T. Tsukagoshi, A. Yoshida, Takasu HashimotoAbstract:This paper describes the experimental results of a 4 K-GM refrigerator, which uses magnetic regenerator materials. The technical point of this study is ascertaining the effects of operational parameters for improving the 4.2 K Refrigeration Capacity. Compressor Capacity and displacer stroke are main parameters in this study. A larger compressor enables a larger Refrigeration Capacity at a smaller temperature difference in the second regenerator. A smaller compressor, however, is preferable to maintain 4.2 K, when temperature difference is large. Displacer strokes of 12, 20 and 32 mm are investigated. The optimum reciprocating speed for the 4.2 K Refrigeration Capacity strongly depends on the displacer stroke. The largest Refrigeration Capacity, however, are almost equal for each of the strokes. In this study, the optimized stroke is found to be 20 mm to obtain Refrigeration capacities at the second stage (4.2 K) and the first stage (40 K) simultaneously.
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Development of 1 Watt Class 4 K Gm Refrigerator with Magnetic Regenerator Materials
Advances in Cryogenic Engineering, 1994Co-Authors: Toru Kuriyama, Hideki Nakagome, H. Nitta, Takasu Hashimoto, Takahashi Masahiko, Masanori YabukiAbstract:This paper describes the experimental results of the 4 K GM refrigerator which obtained the maximum Refrigeration Capacity of 1.05 W at 4.2 K. The COP value for the 4 K GM refrigerator at 4.3 K was 1.92*10-4 and almost same as that for commercially used GM+JT refrigerator at 4.3 K. The technical points of this refrigerator were to adopt a hybrid structural regenerator and to optimize the intake/exhaust valve timing. The hybrid structural regenerator consisted of Ero.9Ybo.1Ni and Er3Co regenerator materials. Ero.9Ybo.1Ni has a large heat Capacity at lower than 10 K. On the other hand, Er3Co has a large heat Capacity at a higher temperature region. The intake/exhaust valve timing was also changed to improve the Refrigeration Capacity at 4.2 K.
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Helium liquefaction by a two-stage Gifford-McMahon-cycle refrigerator using new regenerator material of Er3Ni
Japanese Journal of Applied Physics, 1992Co-Authors: Toru Kuriyama, Hideki Nakagome, Takahashi Masahiko, Tatsuji Eda, Hikaru Seshake, Takasu HashimotoAbstract:This paper describes the experimental results of the two-stage Gifford-McMahon (GM)-cycle refrigerator using a rare-earth compound as a regenerator material. The purpose of this study was to obtain a practical Refrigeration Capacity at 4.2 K, where the lowest temperature for a typical two-stage GM-cycle refrigerator is limited to 8 K. The technical point was to adopt erbium 3 nickel (Er3Ni) as a regenerator material. A Refrigeration Capacity of 0.28 W at 4.2 K was obtained, and the lowest temperature of 3.22 K was achieved. Helium liquefaction by the two-stage GM-cycle refrigerator was also confirmed for the first time.
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Analysis of Rare Earth Compound Regenerators Operating at 4 K
Advances in Cryogenic Engineering, 1992Co-Authors: Hikaru Seshake, Toru Kuriyama, Takasu Hashimoto, Tatsuji Eda, K. Matsumoto, Hideki NakagomeAbstract:This paper describes the analysis of regenerators which consist of rare earth compounds. In a regenerative cycle refrigerator, Refrigeration loss is larger than useful Refrigeration Capacity at liquid helium temperature, and the main loss is regenerator loss. The purpose of this paper is to establish a numerical calculation method which gives useful information for designing high efficiency regenerators. The model regenerator consisted of two regenerator compounds: Er3Ni, which is hot-side material, and another material such as ErNi2, Er0.75Dy0.25Ni2, ErNi, or Er0.9Yb0.1Ni. The regenerator efficiency was calculated for various ratios of the two materials. Regenerator efficiencies for various combinations of rare earth compounds are systematically discussed. The maximum regenerator efficiency was obtained at 4 K with the condition that Er3Ni was 45% and Er0.9Yb0.1Ni was 55% of the regenerator volume. Moreover, it was shown that a refrigerator with this optimized regenerator could achieve a 52% larger Refrigeration Capacity than one with an all-Er3Ni regenerator.
Z R Zhao - One of the best experts on this subject based on the ideXlab platform.
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stable magnetocaloric effect and Refrigeration Capacity in co doped fecomnzrnbb amorphous ribbons near room temperature
Journal of Alloys and Compounds, 2017Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract The Fe-based amorphous alloys are promising candidates for magnetic Refrigeration due to their large magnetocaloric effect, outstanding mechanical property and high electrical resistivity. In this paper, the influence of Co addition on the magnetocaloric effect and Refrigeration Capacity has been studied for Fe 82− x Co x Mn 4 Zr 8 Nb 2 B 4 ribbons. X-ray diffraction patterns indicate that the Co-doped ribbons are amorphous. The Curie temperature can be adjusted from 271 to 363 K with the Co atomic concentration changing from 2 to 8. Favorably, both isothermal entropy change (Δ S T ) and Refrigeration Capacity ( RC ) remain nearly the same magnitude for the Co-doped ribbons. For a field change of 3 T, the maximum −Δ S T is about 1.7 J/kgK and the RC is about 115 J/kg for a temperature span of 80 K. The stable magnetocaloric effect and Refrigeration Capacity near room temperature reveals that the Co-doped amorphous ribbons may be considered as refrigerants for magnetic Refrigeration.
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enhancement of Refrigeration Capacity and table like magnetocaloric effect in la0 8ca0 2mno3 la0 8k0 2mno3 nanocrystalline composite
Ceramics International, 2015Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract In this paper we report on the magnetocaloric effect and Refrigeration Capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247 K and 281 K, respectively. The maximum values of isothermal entropy change ( − Δ S T , max ) are found to be 4.25 J/kg K and 3.71 J/kg K under a magnetic field change of 5 T for LCMO and LKMO, respectively. The composite exhibits a table-like Δ S T curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.
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Enhancement of Refrigeration Capacity and table-like magnetocaloric effect in La0.8Ca0.2MnO3/La0.8K0.2MnO3 nanocrystalline composite
Ceramics International, 2015Co-Authors: G F Wang, Z R Zhao, X F ZhangAbstract:Abstract In this paper we report on the magnetocaloric effect and Refrigeration Capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247 K and 281 K, respectively. The maximum values of isothermal entropy change ( − Δ S T , max ) are found to be 4.25 J/kg K and 3.71 J/kg K under a magnetic field change of 5 T for LCMO and LKMO, respectively. The composite exhibits a table-like Δ S T curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.