• 제목/요약/키워드: external magnetic field

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Magnetic Field Sensor by Using Magnetic Effect in YBaCO Superconductor (자기적 성질을 응용한 YBaCuO계 초전도 자기센서)

  • 이상헌
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.6
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    • pp.491-498
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    • 2001
  • The relationship between electrical properties of YBaCuO superconductor and externally applied magnetic field was studied to develop a magnetic field apolarity sensor. The electrical resistance of the superconductor was increased by applying external magnetic field and even after removal of the magnetic field. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the materials by the external magnetic field. Some portion of the superconductor was changed to a normal state by the trapped magnetic flux. The appearance of the normal state yielded to enhance the electrical resistance. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive to the external magnetic field and showed different responses depending on the direction of the magnetic field. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.

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Magnetic Field Sensor by Using Magnetic Effect in YBaCuO Superconductor (BPSCCO 초전도 자성센서)

  • 이상헌
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.137-139
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    • 2003
  • The relationship between magnetic properties of BiPbSrCaCuO superconductor and externally applied magnetic field was studied to develop a magnetic field polarity sensor. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the material by the external magnetic field. Some portion of the superconductor was changed to a normal state by the trapped magnetic flux. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive to the external magnetic field and showed different responses depending on the direction of the magnetic field.

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Effect of an External AC Magnetic field on Dynamic Resistance and Loss Characteristic in a Bi-2223 Tape (외부 교류자장이 Bi-2223테이프의 동저항 및 손실특성에 미치는 영향)

  • Ryu, Kyung-Woo;Choi, Byoung-Ju
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.5
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    • pp.473-477
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    • 2005
  • A Bi-2223 tape has been developed for power applications such as a fault current limiter, a power cable and a superconducting magnetic energy storage system. In such applications, the Bi-2223 tape carries time varying transport current and in addition experiences time varying external magnetic field. It is well known that the external magnetic field not only causes magnetization loss in the Bi-2223 tape, but also drastically increases transport loss due to a so-called 'dynamic resistance' We developed an evaluation setup, which can measure transport loss in external at magnetic fields. Using this equipment, we measured the dynamic resistances for various amplitudes and frequencies of an external at magnetic field perpendicular to the face in the tape. Simultaneously we investigated the effect of an external ac field on transport loss with different experimental conditions. This paper describes test results ana discussions on correlation between the dynamic resistance and the transport loss for the Bi-2223 tape.

Stability analysis of an insulationless HTS pancake coil under the magnitude of external magnetic field

  • Jung, Sung-Jun;Kim, Gyeong-Hun;Kim, Kwangmin;Park, Minwon;Yu, In-Keun
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.4
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    • pp.41-45
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    • 2012
  • An HTS (high temperature superconducting) coil without insulation has been investigated since a metallic insulation was suggested in the mid-1980s. The advantage of an insulationless HTS pancake coil is that it is more stable than an insulated HTS pancake coil. This paper focuses on the various characteristics of the insulationless HTS pancake coil related with stability, especially under the external magnetic field. Because HTS pancake coil may be influenced by the external magnetic field in a real operational environment of electrical devices. First, charge-discharge test was performed for the characteristics evaluation of the insulationless HTS pancake coil as compared with insulated HTS pancake coil in liquid nitrogen at 77 K. Based on the experiment results, characteristics evaluation of the insulationless HTS pancake coil was implemented under the external magnetic field. In order to carry out the experiment, we have fabricated a cylindrical solenoid coil to apply the magnetic field. The various characteristics of the insulationless HTS pancake coil were evaluated for charge-discharge and over-current conditions. This paper proves that the insulationless HTS pancake coil is more stable than the insulated HTS pancake under the external magnetic field.

Magnetic Properties of BiPbSrCaCuO System (Bi계 초전도체의 자기적 효과)

  • 이상헌
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2002.02a
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    • pp.355-357
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    • 2002
  • The relationship between magnetic properties of BiPbSrCaCuO superconductor and externally applied magnetic field was studied to develop a magnetic field polarity sensor. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the material by the external magnetic field. Some portion of the superconductor was changed to a normal state by the trapped magnetic flux. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive to the external magnetic field and showed different responses depending on the direction of the magnetic field.

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Electromagnetic Chracteristics of Bi System Ceramic Superconductor (Bi계 세라믹재료의 전자기특성)

  • Lee, Sang-Heon
    • Proceedings of the KIEE Conference
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    • 2003.07c
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    • pp.1421-1423
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    • 2003
  • The relationship between magnetic properties of BiPbSrCaCuo superconductor and externally applied magnetic field was studied to develop a magnetic field polarity sensor. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the material by the external magnetic field. Some portion of the superconductor was changed to a normal state by the trapped magnetic flux. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive to the external magnetic field and showed different responses depending on the direction of the magnetic field.

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Effects of an External Magnetic Field on the Magnetic Properties of Sputtered Magnetic Thin Films (스퍼터링 중 외부자기장이 자성박막의 자기적 특성에 미치는 영향)

  • Ahn, Hyun Tae;Lim, Sang Ho;Jee, Kwang Koo;Han, Jun Hyun
    • Korean Journal of Metals and Materials
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    • v.49 no.6
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    • pp.505-513
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    • 2011
  • A magnetic device which enables the application of a strong and uniform magnetic field to thin film during sputtering was designed for controlling the magnetic anisotropy using a three dimensional finite element method, and the effects of the external magnetic field on the magnetic properties of sputtered thin films were investigated. Both the intensity and the uniformity of the magnetic flux density in the sputter zone (50 mm ${\times}$50 mm) was dependent on not only the shape and size of the magnet device but also the magnitude of stray fields from the magnet. For the magnet device in which the distance between two magnets or two pure iron bars was 80-90 mm, the magnetic flux density along the direction normal to the external magnetic field direction was minimum. The two row magnets increased the magnetic flux density and uniformity along the external magnetic field direction. An Fe thin film sputtered using the optimized magnet device showed a higher remanence ratio than that fabricated under no external magnetic field.

Dynamic Resistance Characteristics of a Technical High-Tc Superconductor (실용 고온초전도체의 동저항 특성)

  • Ryu, K.;Choi, B.J.;Kim, H.J.;Seong, K.C.
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1225-1227
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    • 2005
  • A Bi-2223 tape has beer developed for power applications such as a fault current limiter, a power cable and a superconducting magnetic energy storage system. In such applications, the Bi-2223 tape carries time varying transport current and in addition experiences time varying external magnetic field. It is well known that the external magnetic field not only causes magnetization loss in the Bi-2223 tape, but also drastically increases transport loss due to a so-called "dynamic resistance". We developed an evaluation setup, which can measure transport loss in external at magnetic fields. Using this equipment, we measured the dynamic resistances for various amplitudes and frequencies of an external ac magnetic field perpendicular to the face in the tape. Simultaneously we investigated the effect of an external ac field on transport loss with different experimental conditions. This paper describes test results and discussions on correlation between the dynamic resistance and the transport loss for the Bi-2223 tape.

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Analysis of CHAMP Magnetic Anomalies for Polar Geodynamic Variations

  • Kim Hyung Rae;von Frese Ralph R.B.;Park Chan-Hong;Kim Jeong Woo
    • Korean Journal of Remote Sensing
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    • v.21 no.1
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    • pp.91-98
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    • 2005
  • On board satellite magnetometer measures all possible magnetic components, such as the core and crustal components from the inner Earth, and magnetospheric, ionospheric and' its coupled components from the outer Earth. Due to its dipole and non-dipole features, separation of the respective component from the measurements is most difficult unless the comprehensive knowledge of each field characteristics and the consequent modeling methods are solidly constructed. Especially, regional long wavelength magnetic signals of the crust are strongly masked by the main field and dynamic external field and hence difficult to isolate in the satellite measurements. In particular, the un-modeled effects of the strong auroral external fields and the complicated behavior of the core field near the geomagnetic poles conspire to greatly reduce the crustal magnetic signal-to-noise ratio in the polar region relative to the rest of the Earth. We can, however, use spectral correlation theory to filter the static lithospheric and core field components from the dynamic external field effects that are closely related to the geomagnetic storms affecting ionospheric current disturbances. To help isolate regional lithospheric anomalies from core field components, the correlations between CHAMP magnetic anomalies and the pseudo-magnetic effects inferred from satellite gravity-derived crustal thickness variations can also be exploited, Isolation of long wavelengths resulted from the respective source is the key to understand and improve the models of the external magnetic components as well as of the lower crustal structures. We expect to model the external field variations that might also be affected by a sudden upheaval like tsunami by using our algorithm after isolating any internal field components.

Research on a transport characteristic of Bi-2223/Ag superconducting tapes with time-varying magnetic field (시변자장 영향에 따른 Bi-2223/Ag 선재의 통전 특성에 대한 연구)

  • Choi S.J.;Lee S.J.;Kim H.J.;Sim K.D.;Cho J,W.
    • Progress in Superconductivity and Cryogenics
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    • v.8 no.3
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    • pp.59-62
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    • 2006
  • For electric power applications of Bi-2223/Ag superconducting tapes, a transport characteristic is important issue. A transport characteristic is strongly depends on the magnitude and direction of external time-varying magnetic field. To verify a effect of external magnetic field, we manufactured a prototype magnet and obtained transport characteristics with respect to the magnitude, the direction and the frequency of external magnetic field. The data acquired in this paper will be used as a source for the study of HTS electric power applications which is supposed to carry on.