• 제목/요약/키워드: Magnetic Materials

검색결과 3,896건 처리시간 0.036초

상전도 흡인식 자기부상열차용 전자석에 대한 실험적 연구( IV ) (An Experimental Study on Magnet for Electro-Magnetic Maglev Vehicle( IV ))

  • 김봉섭;정현갑;유문환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 A
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    • pp.67-73
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    • 1997
  • A magnet for urban transit Maglev is designed, analyzed and experimented to evaluate and to improve its characteristic. FEM is also used to calculate magnetic field density, magnetic force, leakage flux and losses. Seven cases of magnets are analyzed and tested for verifying the calculated characteristics and for optimizing the shape. Using the results, an improved levitation magnet is proposed for the vehicle.

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Structure and Magnetic Properties of Sm-Co(x nm)/Co(6 nm) Multi-layered Nanocomposite Films

  • Yang, Choong-Jin;You, Cai-Yin;Zhang, Zhi-Dong
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2002년도 동계연구발표회 논문개요집
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    • pp.24-25
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    • 2002
  • Tthe structure and magnetic properties of Sm-Co/co films treated at various annealing temperatures and times are reported, The effects of an externally applied magnetic field during annealing, were also investigated. These result is discussed in terms of magnetization reversal of nano grains which seems to compete with the exchange interaction occurring between the nano grains. (omitted)

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Ferromagnetic Semiconductors: Preparation and Properties

  • 조성래
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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    • pp.19-19
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    • 2003
  • The injection of spins into nonmagnetic semiconductors has recently attracted great interest due to the potential to create new classes of spin-dependent electronic devices. A recent strategy to achieve control over the spin degree of freedom is based on dilute ferromagnetic semiconductors. Ferromagnetism has been reported in various semiconductor groups including II-Ⅵ, III-V, IV and II-IV,-V$_2$, which will be reviewed. On the other hand, to date the low solubility of magnetic ions in non-magnetic semiconductor hosts and/or low Curie temperature have limited the opportunities. Therefore the search for other promising ferromagnetic semiconducting materials, with high magnetic moments and high Curie temperatures (Tc), is of the utmost importance. In this talk, we also introduce new pure ferromagnetic semiconductors, MnGeP$_2$ and MnGeAs$_2$, exhibiting ferromagnetism and a magnetic moment per Mn at 5K larger than 2.40 ${\mu}$B. The calculated electronic structures using the FLAPW method show an indirect energy gap of 0.24 and 0.06 eV, respectively. We have observed spin injection in MnGeP$_2$ and MnGeAs$_2$ magnetic tunnel junctions through semiconducting barriers.

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아몰포스선을 이용한 전력선의 자계분포 (Magnetic Field Distribution of Power Line Using Amorphous Wire)

  • Moriyama, T.;Cho, M.W.;Hikita, M.;Hong, J.W.
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.609-612
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    • 2001
  • To investigate the magnetic field distribution of power line, we used amorphous wire sensor. And we discuss extremely low frequency magnetic field distribution dependent upon arrangement of power line and shielding pipe made from iron or alumimum materials by both measurement and FEM(Finite Element Method) analysis. Appling current of single phase 60 [Hz] 15 [A] is supplied to copper wire coated enamel resign. As the results, we confirmed that linear characteristics of amorphous wire sensor is very excellent and measurement value agrees with FEM calculation. Magnetic field distribution due to shielding materials is changed by permeability and conductivity.

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재질과 자기장 세기가 자기유변유체의 마찰 특성에 미치는 영향 (A Study on the Effect of the Material and Applied Magnetic Field Strength on the Friction Characteristics of Magnetorheological Fluids)

  • 장붕;이광희;이철희
    • Tribology and Lubricants
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    • 제29권1호
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    • pp.39-45
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    • 2013
  • Magnetorheological (MR) fluid belongs to the group of smart materials. In MR fluid, iron particles in base oil form chains in the direction of the applied magnetic field, thus resulting in a variation in the stiffness and damping characteristics of the fluid. Research is being carried out on controlling the stiffness and damping characteristics as well as the tribological characteristics of the MR fluid. In this study, the friction characteristics of MR fluid have been evaluated using three types of materials and magnetic fields of different strengths. The coefficients of friction of the three types of MR fluid are measured, and the relationship between the coefficient of friction and the strength of the applied magnetic field is obtained.

Synthesis of Nanomaterials such as fluorescent-magnetic Nanoclusters and Frequency Doubling Nanowires for Bioapplications

  • Jeong, Jinhoo;Kim, Seungwook;Kim, Woong
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.132.1-132.1
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    • 2014
  • Fluorescent-magnetic nanoclusters were synthesized for biomedical applications. The nanoclusters consisted of superparamagnetic core-nanoclusters, highly fluorescent shell of nanocrystals, and lipid A. Magnetic cores were used for both magnetic resonance imaging (MRI) and cell separation. Fluorescent shell was used for optical imaging. The lipid-A-loaded nanoclusters were up-taken by dendritic cells via phagocytosis, which successfully activated dendritic cells. The dendritic cells were migrated to lymph nodes and spleen of mice. The results showed that our novel nanoclusters can play a role as an efficient optical and magnetic imaging, a cell separating and a pathogen mimetic agent at the same time. Additionally, synthesis of wavelength conversion nanowires will be discussed, which may be used as an optical nanoprobe in biological studies.

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Nanocomposite magnetic powder materials using mechanochemical Synthesis

  • Soh, Dae-Wha;Mofa, N.N.;Keteguenov, T.A.;Mansurov, Z.A.
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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    • pp.585-587
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    • 2002
  • The materials showing high structure dispersity are developed on the quartz base and they are obtained by mechano-chemical technology. Depending on the processing conditions and subsequent applications the materials produced by mechano-chemical reaction show concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, contain a dielectric material as a canγing nucleus, particularly the quartz on that surface one or more layers of different compounds are synthesized having thickness up to 10~50 nm and showing magnetic, electrical and other properties.

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Aqueous Processing of Textured Silicon Nitride Ceramics by Slip Casting in a Strong Magnetic Field

  • Zhu, Xinwen;Uchikoshi, Tetsuo;Sakka, Yoshio
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.866-867
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    • 2006
  • This work will report a highly textured ${\beta}-Si_3N_4$ ceramic by aqueous slip casting in a magnetic field and subsequent pressureless sintering, Effects of the sintering aids, polymer dispersant, pH and stirring time on the stability of the $Si_3N_4$ slurries were studied. The textured ${\beta}-Si_3N_4$ with 97 % relative density could be obtained by slip casting in a magnetic field of 12 T and subsequent sintering at $1800^{\circ}C$ for 1 h. The textured microstructure is featured by the alignment of c-axis of ${\beta}-Si_3N_4$ crystals perpendicular to the magnetic field, and the Lotgering orientation factor, f, is determined to be 0.8.

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Effect of structural change on the magnetostriction coefficient in the CoCrPt alloy thin films

  • Im, Mi-Young;Jeong, Jong-Ryul;Shin, Sung-Chul
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2002년도 동계연구발표회 논문개요집
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    • pp.178-179
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    • 2002
  • CoCrPt alloy films are one of the most promising candidates for high-density perpendicular magnetic recording media due to their strong perpendicular magnetic anisotropy (PMA) and high coercivity [1]. In order to achieve high-density magnetic recording media, it is essential to characterize the magnetoelastic properties since experimental and theoretical research has revealed a significant magnetoelastic contribution to the magnetic properties in magnetic thin films. (omitted)

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An Open Gradient Magnetic Separator Assembled Using NdFeB Magnets for a Use of Fine Particles Remover

  • Park, Eon-Byung;Choi, Seung-Duck;Yang, Choong-Jin;Lee, Won-Sub
    • Journal of Magnetics
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    • 제3권3호
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    • pp.69-73
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    • 1998
  • A drum type magnetic separator was designed and optimized by computer simulation. The separator consisted of rotating outer shell of drum, magnetic flux generator drum which was assembled with numbers of disk type magnet holders, and drum axis around which the magnet holders were fixed. NdFeB magnet blocks were inserted into the disks, and the disks were assembled layer by layer along the drum axis. Magnetic circuits of the separator were simulated on the basis of highest magnetic strength, least cost, and high yield of separation by using a Vector Field S/W employing the Opera-2D program. The separator proved a separation yield of 95% in removing fine iron-base particles, and installed at Hot Rolling Mill of Pohang Iron & Steel Co. In Korea.

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