• Title, Summary, Keyword: magnetic field

Search Result 5,371, Processing Time 0.054 seconds

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
    • /
    • v.14 no.6
    • /
    • pp.491-498
    • /
    • 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.

  • PDF

The Influence of Magnetic Field on Diffusion Flames: Role of Magnetic Field On/Off Frequency and Duty Ratio (자기장 분포가 확산화염의 연소특성에 미치는 영향: 자기장 On/Off 주기와 Duty Ratio의 역할)

  • Lee, Won-Nam;Bae, Seung-Man
    • Journal of the Korean Society of Combustion
    • /
    • v.17 no.1
    • /
    • pp.58-65
    • /
    • 2012
  • The influence of magnetic field on propane and acetylene diffusion flames have been experimentally investigated using an electromagnetic system. Periodically induced magnetic field having various frequencies and duty ratios was established in square wave form. The maximum intensity and gradient of magnetic field were 1.3 T and 0.27 T/mm, respectively. The width of a propane flame was reduced up to 4.5% and the brightness was enhanced up to 25% when the magnetic field was induced. The soot emission from an acetylene flame was ceased when magnetic field was induced. The alteration of flow field, which is due to the paramagnetic characteristics of oxygen molecule, is most likely to be responsible for the change in flame size and brightness. The effect of magnetic field on diffusion flames, which competes with the gravitational effect, was more apparent from a smaller size flame. The magnetic field effect, therefore, could be important under microgravity conditions. Since the time required to alter the flow field must be finite, the magnetic field effect is likely to be less significant for a periodically oscillating magnetic field at a high frequency or having a small duty ratio.

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
    • /
    • /
    • pp.137-139
    • /
    • 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.

  • PDF

Correlation between Density and Magnetic Field in Compressible MHD Turbulence

  • Yoon, Hee-Sun;Cho, Jung-Yeon
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.36 no.1
    • /
    • pp.86.1-86.1
    • /
    • 2011
  • Most astrophysical systems are turbulent and magnetized. Magnetic field plays an important role in the dynamics of ISM and influence all of properties of astrophysical system. Information of magnetic field is very important to understand properties of astrophysical systems. For example, one way to obtain information of magnetic field is to use Rotation Measure. Mean strength of the magnetic field along the line of sight can be estimated from RM/DM. (where RM is rotation measure, DM is dispersion measure) For the estimation of magnetic field strength using RM/DM, the correlation between density and magnetic field is very important. When there is no correlation between density and magnetic field the relation gives exact mean magnetic field strength. But, if the correlation is positive, it overestimates the magnetic field strength, while if the correlation is negative, it underestimate the strength. We calculate correlation between density and magnetic field in compressible MHD turbulence.

  • PDF

A Study on Magnetic Signature Analysis Techniques of a Scaled Model Ship using Earth Magnetic Field Simulator (지구자기장 시뮬레이터를 이용한 모델 함정의 자기신호 분석 기법 연구)

  • Yang, Chang-Seob;Chung, Hyun-Ju;Jeon, Jae-Jin
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.16 no.4
    • /
    • pp.465-472
    • /
    • 2013
  • Since 1990, Agency for Defense Development is operating the non-magnetic laboratory for the development of key technology for the underwater magnetic stealth part, the research of the magnetic application weapons and the technical support for Korean Navy. Recently, we installed the new three-axis earth magnetic field simulator and the measurement system in the non-magnetic laboratory which is replacing the existing outdated facility. In this paper, we deal with the detailed design result of the earth magnetic field simulator and the measurement system. Also, we describe the effective method to separate the permanent and the induced magnetic field from the measured data for a scaled model ship using the earth magnetic field simulator and the measurement system.

Estimate the Magnetic Field Strength using rotation measure

  • Yoon, Hee-Sun;Cho, Jung-Yeon
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.36 no.2
    • /
    • pp.107.2-107.2
    • /
    • 2011
  • Most astrophysical systems are turbulent and magnetized. Magnetic field plays an important role in the dynamics of astrophysical system and influence all of properties of astrophysical system. Therefore, information of magnetic field is very important to understand properties of astrophysical system. One way to obtain information of magnetic field is to use rotation measure. Mean strength of the magnetic field along the line of sight can be estimated from RM/DM, where RM is rotation measure and DM is dispersion measure. For the estimation of magnetic field strength using RM/DM, the correlation between density and magnetic field. When there is no correlation between density and magnetic field the relation gives exact mean magnetic strength. But if the positive correlation, it overestimates the magnetic field strength, while if the correlation is negative, it underestimate the magnetic field strength. In general, the ICM (intracluter medium) and the ISM (interstellar medium) cases, viscosity has a value greater than magnetic diffusion. We performed compressible MHD turbulence simulations and we studied correlation between density and magnetic field in different values of viscosity and magnetic diffusion. In most cases, we found weak or negative relations between the density and magnetic fields. We discuss implication of our results.

  • PDF

A Magnetic Field Separation Technique for a Scaled Model Ship through an Earth's Magnetic Field Simulator

  • Chung, Hyun-Ju;Yang, Chang-Seob;Jung, Woo-Jin
    • Journal of Magnetics
    • /
    • v.20 no.1
    • /
    • pp.62-68
    • /
    • 2015
  • This paper presents an experimental technique to accurately separate a permanent magnetic field and an induced one from the total magnetic fields generated by a steel ship, through compensating for the Earth's magnetic field. To achieve this, an Earth's magnetic field simulator was constructed at a non-magnetic laboratory, and the field separation technique was developed, which consisted of five stages. The proposed method was tested with a scaled model ship, and its permanent and induced magnetic fields were successfully extracted from the magnetic field created by the ship. Finally, based on the separated permanent magnetic field data, the permanent magnetization distribution on the hull was predicted by solving an inverse problem. Accordingly, the permanent magnetic fields generated by the ship can easily be calculated at any depth of water.

Position Estimation Using Magnetic Field Map (자기장 지도를 이용한 위치 추정)

  • Kim, Han-Sol;Moon, Woo-Sung;Seo, Woo-Jin;Baek, Kwang-Ryul
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.19 no.4
    • /
    • pp.290-298
    • /
    • 2013
  • Geomagnetic is refracted by building's wall and pillar. Therefore refracted geomagnetic is able to be used as feature point. In a specific space, a mobile device that is equipped with magnetic sensor array measures 3-axis magnetic field for each point. Magnetic field map is acquired by collecting the every sample point in the magnetic field. The measured magnetic field must be calibrated, because each magnetic sensor has a distortion. For this reason, sensor distortion model and sensor calibration method are proposed in this paper. Magnetic field that is measured by mobile device matches magnetic field map. Result of the matching is used for position estimation. This paper implements hardware system for position estimation method using magnetic field map.

A Study on the Effects of Magnetic Field and BEP on Hyperlipidemia and Enzymatic Activities in Rats (자기장(磁氣場) 및 BEP 조사(照射)가 식이성(食餌性) 고지혈증(高脂血症)이 유발(誘發)된 흰쥐에 미치는 영향(影響)에 대(對)한 연구(硏究))

  • Koh, Kwang-chan;Lee, Cheol-wan
    • Journal of Haehwa Medicine
    • /
    • v.8 no.1
    • /
    • pp.559-592
    • /
    • 1999
  • It has been known that Ki(氣) energy is very effective on many adult diseases. Oriental Medicine has acknowledged Ki as an existing reality and investigated its effects on the body. However, the existence of Ki has not been fully explained. In order to find a conclusive evidence on the existence of Ki, this experiment was done to study the mutual relationship of Ki with a magnetic field and BEP (biological energy projector). The BEP apparatus was irradiated under the magnetic field on rats in the hyperlipidemic induced state. Following criterias were measured in this experiment: weight change, weight of the visceral organs, serum, hepatic lipid peroxide, bleeding time, tissue factor, and etc. The following results were obtained in this study: 1. The weight of rat significantly decreased in the magnetic field treated group and radically reduced in the group treated with both magnetic field and BEP. 2. The weight of liver, heart, and kidney increased in both the magnetic field treated group and magnetic field+BEP group compared to the normal group, but decreased in comparison to the control group. No changes were witnessed in the weight of spleen. 3. Serum and hepatic total cholesterol, total lipid, and lipid peroxide level significantly decreased in both magnetic field treated group and magnetic field+BEP treated group, while lipase activity has increased noticeably. 4. Serum HDL showed a significant increase in both magnetic field treated group and magnetic field+BEP treated group compared to the control group, while LDL and VLDL level decreased significantly. 5. A bleeding time significantly increased in both magnetic field treated group and magnetic field+BEP treated group compared to the control group. A tissue factor value of the lung decreased in the magnetic field treated group and magnetic field+BEP treated groups while increased in the control group. 6. Serum and hepatic lipid peroxide and glutathione level were significantly decreased in the magnetic field treated group and magnetic field+BEP treated group, while hepatic glutathione level was significantly increased compared to the control group. 7. A significant increase was found in the serum hydroxyl radical and SOD activity in the dietary hyperlipidemic rats, and significant decrease was found in the serum lipid peroxide content and superoxidase activity. 8. Hepatic cytosolic enzyme xanthine oxidase and aldehyde oxidase showed a significant decrease in the magnetic field treated group and magnetic field+BEP treated group. Through the above experimental results, one can suggest that the magnetic field with BEP can suppress hyperlipidemia and boost lipid metabolism and restructuring a lipid in liver, which increases the function of liver. To conclude, BEP is considered to show more potent effects under the exposure of magnetic field because magnetic field seems to increase the flow of Ki in the body.

  • PDF