• 제목/요약/키워드: tangential field

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Torque Characteristics of Switched Reluctance Motor in Nonuniform airgap field (불균일한 공극길이에서의 스위치드 리럭턴스 모터 토오크 특성)

  • Jung, Do-Young;Lee, Sang-Ho;Oh, Hong-Seok
    • Proceedings of the KIEE Conference
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    • 1999.07a
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    • pp.188-190
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    • 1999
  • This paper analyzed the static torque of SRM according to the variation of airgap length using Finite Element Method. The normal and tangential components of flux density are analyzed at uniform airgap field which sap length is 0.3[mm] and nonuniform airgap which gap lengths are 0.2-0.4[mm] and 0.4-0.2[mm]. Also their static torques were simulated by using Virtual Work Principle. We expect that their parameters will help for the design of Switched Reluctance Motor.

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Characteristic Analysis of Linear Induction Motor Considering Multi-Region Traveling-wave problems (다중층 해석법을 이용한 직선형 유도전동기의 특성 해석)

  • Jang, Seok-Myeong;Cho, Sung-Kook;Lee, Sung-Ho;Cho, Han-Wook;Kweon, Jung-Ki
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1033-1035
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    • 2003
  • Linear induction motor with multilayer region of the single-sided is analyzed considering multi region traveling wave problem. A hybrid method of analysis consisting of field analysis in conjunction with the multilayer transfer matrix concept with adjustment of secondary iron permeability to match the tangential magnetizing field in each layer is developed.

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A Trial of 6 MV Linear Accelerator Radiation Therapy (RT) for Breast Cancer (6 MV 선형가속기를 사용한 유방암 치료)

  • Lee Guy Won;Park Ju Seon;Kim Geol;Yoon Sei Chul
    • The Journal of Korean Society for Radiation Therapy
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    • v.1 no.1
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    • pp.37-42
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    • 1985
  • Radiation Therapy(RT) has been used in the treatment of breast cancer for over 80 years. Technically, it should include a part or all of such areas as chest wall or breast, axilla, internal mammary nodes(IM) and supraclavicular nodes (SCL). Authors tried three-field technique for the treatment of breast cancer using 6 MV linear accelerator, exclusively the department of Radiology, Kang-Nam St. Mary's Hospital, at Catholic Medical College. The field junction was checked by a phantom study and radiation doses measured by film densitometry and TLD. The 3 fields we used in this study were two isocentric opposing tangential fields encompassing the breast, chest wall and occasionally IM and one single anterior field encompassing the axilla and SCL. Using appropriate beam blocks and blouses, we were able to avoid unwanted intrinsic divergency of photon beam. Blocking also enabled us to set-up precise radiation field with ease.

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A Trial of 6-MV Linear Accelerator Radiation Therapy (RT) for Breast Cancer (6MV 선형가속기를 사용한 유방암 치료)

  • Yoon S. C.;Kwon H. C.;Oh Y. K.;Kim J. W.;Bahk Y. W.
    • Radiation Oncology Journal
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    • v.2 no.2
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    • pp.303-309
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    • 1984
  • Radiation therapy(RT) has been used in the treatment of breast cancer for over 80years. Technically, it should include a part or all of such areas as chest wall or breast, axilla, internal mammary nodes (IM) and supraclavicular nodes (SCL). Authors tried three-field technique for the treatment of breast cancer using 6-MV linear accelerator, exclusively the department of radiology. Kang-Nam St. Mary's Hospital, at Catholic Medical College. The field junction was checked by a Phantom study and radiation doses measured by film densitometry and TLD. The 3 fields we used in this study were two isocentric opposing tangential fields encompassing the breast, chest wall and occasionally IM and one single anterior field encompassing the axilla and SCL. sing appropriate beam blocks and boluses, we were able to avoid unwanted intrinsic divergency of photon beam. Blocking also enabled us to set-up precise radiation field with ease.

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Automatic Surface Generation for Extrusion Die of Arbitrarily Shaped Section using B-spline Surfaces and Scalar Field Theory (B-스플라인 곡면과 스칼라장 이론을 이용한 임의의 형상의 압출금형 곡면의 자동생성)

  • 임종훈;김광혁;유동진;양동열
    • Transactions of Materials Processing
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    • v.13 no.1
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    • pp.33-38
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    • 2004
  • A new approach for the design of extrusion die surface of arbitrarily shaped section is presented. In order to generate the extrusion die surface. an automatic surface construction method based on B-spline surface and scalar field theory is proposed. The isothermal lines and stream lines designed in the scalar field are introduced to find the control points which are used in constructing B-spline surfaces. Intersected points between the isothermal lines and stream lines are used to construct B-spline surfaces. The inlet and outlet profiles are precisely described with B-spline curves by using the centripetal method for uniform parameterization. The extrusion die surface is generated by using the cubic curve interpolation in the u- and v-directions. A quantitative measure for the control of surface is suggested by introducing the tangential vectors at the inlet and outlet sections. To verify the validity and effectiveness of the proposed method, automatic surface generation is carried out for extrusion dies of arbitrarily shaped sections.

Mechanical Analysis of Field Coil Deformation in Gas Turbine Generator (가스터빈 발전기의 계자권선 손상에 관한 역학적 분석)

  • Han, Seok-Woo;Kwon, Young-Dong;Choe, Gyu-Ha
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.107-109
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    • 1998
  • This paper presents mechanical analysis of gas turbine generator (113MVA, $3{\phi}$, 2P, 0.9PF, F class, 3600rpm, 60Hz, 13.8kV, 4.72kA, Air-Cooling) field coil deformation. Rotor end coil deformation is only appeared on turbine end but collector end coil is normal. Expansion direction of end coil is tangential not axial. Deformation appears more severe at top turn. Retaining ling is expanded by centrifugal force of coil and itself. In case friction coefficient between coil top surface and retaining ring insulation inner surface is small, coil end length ${\ell}$ does not change. However, in case friction coefficient big condition, coil end is expanded ${\Delta}{\ell}$ due to start and stop. Deformation is assumed about 30mm by watching photograph inner surface of retaining ring is coated by Teflon at manufacturing condition. Usually Teflon coating insulation surface is small friction coefficient. It's value 0.08${\sim}$0.15. However it's value exceeds more than 0.297. Since top turn deformation appears. The distortion and subsequent failure have occurred because of the lack of a sufficient slip-plane between the top field coil conductors and the inside surface of the retaining ring insulation on the turbine end of the field-winding.

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Near-field Evaluation of Surface Plasmon Resonance Biosensor Sensitivity Based on the Overlap Between Field and Target Distribution (근접장-분자반응 간의 중첩을 이용한 표면 플라스몬 공명 센서 감도 평가에 관한 연구)

  • Ryu, Yeonsoo;Son, Taehwang;Kim, Donghyun
    • Korean Journal of Optics and Photonics
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    • v.24 no.2
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    • pp.86-91
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    • 2013
  • In this study, we have investigated the correlation of far-field detection sensitivity of surface plasmon resonance (SPR) biosensors with optical signatures associated with the near-field overlap of biomolecules. The results confirm a direct relation between the far-field and near-field parameters, particularly for optical signatures defined in terms of lateral electric field components that are tangential to the interface and thus continuous across the interface. The overall correlation between near-field optical signatures and far-field resonance shift exceeded 97%. The results can be highly useful to evaluate detection sensitivity of SPR biosensors that take advantage of complex structures for localization of surface waves.

A Comparison of Field-in-Field Intensity Modulated Radiation Therapy Planning and Conventional Radiation Therapy Planning with Tangential Beam for Breast Cancer (유방암의 접선조사 시 Field-in-Field Intensity Modulated Radiation Therapy와 Conventional Radiation Therapy의 전산화 치료계획에 관한 고찰)

  • Yoo, Soon-Mi;Yeom, Mi-Suk;Kim, Dae-Sup;Back, Geum-Mun;Kwon, Kyeong-Tae
    • The Journal of Korean Society for Radiation Therapy
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    • v.22 no.1
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    • pp.41-46
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    • 2010
  • Purpose: To analyze differences in the dose uniformity for the computed breast radiation therapy planning with tangential beam between conventional RT using wedge filter and FiF-IMRT using multileaf collimator based onsizes and volumes of breasts. Materials and Methods: Thirty breast cancer patients were classified according to the sizes and volumes of the breasts using Eclipse treatment planning system ($Varian^{TM}$, USA, V8.0). Conformity Index and Homogeneity Index were computed along with Dose Volume Histogram. Results: No differencein CI (${\pm}1.2%$) was observed. However, lower mean HI (1.67%) in FiF-IMRT was observed compared to that of the conventional RT. Statically significant (P<0.01) correlation was identified between the values of ${\Delta}HI$ (%) and physical parameters such as breast volumes and separations. Conclusion: Increase in breast volume and separation improves the dose uniformities in computed radiation therapy planning for FiF-IMRT. Physical dimension of the breast should be considered to optimize the compured radiation therapy planning.

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A magneto-thermo-viscoelastic problem with fractional order strain under GN-II model

  • Deswal, Sunita;Kalkal, Kapil Kumar;Sheoran, Sandeep Singh
    • Structural Engineering and Mechanics
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    • v.63 no.1
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    • pp.89-102
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    • 2017
  • In this work, we present a theoretical framework to study the thermovisco-elastic responses of homogeneous, isotropic and perfectly conducting medium subjected to inclined load. Based on recently developed generalized thermoelasticity theory with fractional order strain, the two-dimensional governing equations are obtained in the context of generalized magnetothermo-viscoelasticity theory without energy dissipation. The Kelvin-Voigt model of linear viscoelasticity is employed to describe the viscoelastic nature of the material. The resulting formulation of the field equations is solved analytically in the Laplace and Fourier transform domain. On the application of inclined load at the surface of half-space, the analytical expressions for the normal displacement, strain, temperature, normal stress and tangential stress are derived in the joint-transformed domain. To restore the fields in physical domain, an appropriate numerical algorithm is used for the inversion of the Laplace and Fourier transforms. Finally, we have demonstrated the effect of magnetic field, viscosity, mechanical relaxation time, fractional order parameter and time on the physical fields in graphical form for copper material. Some special cases have also been deduced from the present investigation.

Construction of a 40-channel SQUID System and Its Application to Neuromagnetic Measurements

  • Lee, Y.H.;Kim, J.M.;Kwon, H.C.;Park, Y.K.;Park, J.C.;Lee, D.H.;Ahn, C.B.
    • Progress in Superconductivity
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    • v.2 no.1
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    • pp.20-26
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    • 2000
  • A 40-channel superconducting quantum interference device (SQUID) system was constructed for measuring neuromagnetic fields. Main features of the system are the use of double relaxation oscillation SQUIDs (DROSs), and planar gradiometers measuring magnetic field components tangential to the head surface. The DROSs with high flux-to-voltage transfers enabled direct readout of the SQUID output by room-temperature dc preamplifiers and simple flux-locked loop circuits could be used for SQUID operation. The pickup coil is an integrated first-order planar gradiometer with a baseline of 40 mm. Average noise level of the 40 channels is around 1.2 $fT/cm/{\surd}Hz$ at 100 Hz, corresponding to a field noise of 5 $fT/{\surd}Hz$, operated inside a magnetically shielded room. The SQUID insert was designed to have low thermal load, minimizing the loss of liquid helium. The constructed system was applied to measure auditory-evoked neuromagnetic fields.

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