• Title/Summary/Keyword: pole piece

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Analysis of the Magnetic Fluid Seals considering the Surface Configuration (자성유체 형상변화를 고려한 밀봉시스템의 해석)

  • Kim, Dong-Hun;Park, Gwan-Soo;Hahn, Song-Yop
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.945-947
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    • 1993
  • This paper presents the numerical algorithm that can obtain the surface configuration of the magnetic fluid seals. The magnetic field is computed by nonlinear finite element method considering the saturation of magnetic fluid and pole piece. The surface equilibrium condition in ferrohydrodynamics are used in algorithm. The influence of the surface configuration on the sealed pressure due to the magnetic, centrifugal and gravitational forces is analyzed and compared with other experimental results.

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Development of Single-piece Composite Bushing for High Voltage Switch (고압개폐기용 일체형 복합붓싱 개발)

  • Choi, K.S.;Joo, J.M.;Lee, Y.S.;Yu, K.Y.
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1059-1061
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    • 2005
  • The bushing currently applied to pole-mounted type loadbreak switch has porcelain bushing which is connected with the mold cone. This type has potential problems of uncertainty of sealing of the interface part and gas leakage on the connected part between bushing and switch tank due to the weight of the porcelain. The Composite Bushing can solve these problems and also the secondary problem of the potential accident owing to the fragment of the porcelain bushing in breakage due to the outer impact.

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A Study on Design and Analysis for Magnetic Lenses of a Scanning Electron Microscope using Finite Element Method (유한요소법을 사용한 주사전자 현미경의 전자렌즈 설계 및 해석에 관한 연구)

  • Park, Keun;Jung, Hyun-Woo;Park, Man-Jin;Kim, Dong-Hwan;Jang, Dong-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.9
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    • pp.95-102
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    • 2007
  • The scanning electron microscope (SEM) is one of the most popular instruments available for the measurement and analysis of the micro/nano structures. It is equipped with an electron optical system that consists of an electron beam source, magnetic lenses, apertures, deflection coils, and a detector. The magnetic lenses playa role in refracting electron beams to obtain a focused spot using the magnetic field driven by an electric current from a coil. A SEM column usually contains two condenser lenses and an objective lens. The condenser lenses generate a magnetic field that forces the electron beams to form crossovers at desired locations. The objective lens then focuses the electron beams on the specimen. The present work concerns finite element analysis for the electron magnetic lenses so as to analyze their magnetic characteristics. To improve the performance of the magnetic lenses, the effect of the excitation current and pole-piece design on the amount of resulting magnetic fields and their peak locations are analyzed through the finite element analysis.

Avoidance of Internal Resonances in Hemispherical Resonator Assemblies from Fused Quartz Connected by Indium Solder

  • Sarapuloff, Sergii A.;Rhee, Huinam;Park, Sang-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.835-841
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    • 2013
  • Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

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Implant Breast Reconstruction Using Porcine Dermal Matrix ($Permacol^{(R)}$): A Comparative Study with Acellular Cadaveric Dermis ($AlloDerm^{(R)}$) (돼지진피조직(Porcine Dermal Matrix, $Permacol^{(R)}$)을 이용한 보형물 유방재건술: 무세포성 사체 진피 (Acellular Cadaveric Dermis, $AlloDerm^{(R)}$)와 비교 연구)

  • Jeong, Bo-Rham;Roh, Tai-Suk;Kim, Young-Seok;Hong, Jong-Won;Rah, Dong-Kyun
    • Archives of Plastic Surgery
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    • v.38 no.5
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    • pp.559-566
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    • 2011
  • Purpose: The use of tissue expander/implant in breast reconstruction using tissue expander-implant is one of the most common surgical procedures. The use of AlloDerm as a sling to reestablish the lower pole of the pectoralis major muscle results a decrease in morbidity compared with more invasive procedures. However the use of AlloDerm is more expensive than other options. We decided to compare AlloDerm with Permacol, which has been safely used in human body reconstruction and is less costly than AlloDerm. Methods: After mastectomy, the inferolateral origin of the pectoralis major muscle was elevated. Either AlloDerm or Permacol was sutured to the chest wall at the level of the previously marked inframammary fold. The lower border of the pectoralis major muscle and the upper portion of the crescent-shaped piece of either AlloDerm or Permacol was sutured together using a tension free technique, and a tissue expander was subsequently inserted into the subpectoral-subAlloDerm (or Permacol) dual pocket. Results: AlloDerm was used in twenty-one patients (28 breasts) and Permacol was used in six patients (11 breasts) for tissue expander-implant breast reconstruction. During the mean follow-up period of 17 months (8~25 months). Two infections (7%) occurred in AlloDerm cases and four infections (36%) occurred in Permacol cases. Conclusion: This study is the first comparison of tissue expander/implant breast reconstruction using AlloDerm and Permacol. The use of Permacol resulted in more postoperative infection compared with the use of AlloDerm. This report is still limited with the small number of cases studied.

Abstruseness of Rimbaud's Barbare : Autotextuality and Meaning (랭보의 「야만」의 난해성 : '자기텍스트성'과 '의미')

  • Shin, Ok-Keun
    • Cross-Cultural Studies
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    • v.43
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    • pp.327-354
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    • 2016
  • Rimbaud's prose poem, Barbare in Illuminations, is known for its abstruseness with regard to forms, themes, metaphors. This paper first analyzes the poem's grammatical structure to make sense of such an inscrutable piece of work, then discusses its autotextuality in order to decipher its meaning by comparison with Rimbaud's other works. Autotextuality, a method of literary interpretation of Rimbaud's prose poem presented by Steve Murphy, refers to the intertextuality between the author's works. Despite some previous researches focusing on the intertextuality of Barbare, previous authors have failed not only to find its meaning but also to determine its significance. The abstruseness of Rimbaud's Barbare is sometimes considered an example of the meaningless of Rimbaud's work. However, examining the textual structure and the autotextuality builds meaning, rather than rendering the work meaningless. Barbare which consists entirely of noun phrases and metaphors means destruction, fusion and the pure power of regeneration in the original context of Rimbaud's work. This poem is Rimbaud's answer to Baudelaire's poetic question, Any of where out of World, and presents a strange scenery that uses 'the eternal female voice' to reach the Vulcan in the North Pole. Interpretation of Barbare could provide a methodology for reading the difficult Illuminations. The kind of analyses used are, for example, analysis of the text, analysis of verbal indicators, autotextuality, and an understanding of the joy and the solitude in the silence of the poem. Understanding Barbare may provide a method of interpreting the abstruseness of Illuminations. Through this approach, we can connect and combine every fragment of the Illuminations, so that we can reconstruct the story and the adventure contained therein.