• Title/Summary/Keyword: Electrical engineering

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Research of the driving characteristic in the electromagnetic launcher by swiching circuit (스위칭 회로를 이용한 electromagnetic launcher의 동작특성에 관한 연구)

  • Han, Jae-Man;Joo, Sung-Joong;Joo, Ji-Ung;Lee, Man-Sung;Park, Dong-Suk;Park, Je-Uk;Byun, Jong-Hyuk;Kim, Dong-Sok;Park, Gwan-Soo
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.595-596
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    • 2006
  • Electro-magnetic launcher(EML)는 전자기력을 이용하여 발사체를 추진시키는 장치이다. EML은 크게 레일건의 형태와 코일건의 형태로 구분되며, 본 논문에서는 코일건의 형태로 설계, 제작하였다. 코일건의 형태인 EML은 솔레노이드에 여자되는 전류에 의해서 발사체에 흡인력이 발생하여 추진, 가속되므로 솔레노이드의 최적형태를 설계하고, 이를 바탕으로 제작하여 EML의 스위칭 시간에 따른 속도를 측정하여 여자전류의 스위칭 시간에 따른 동작특성을 해석, 실험하여 분석하였다.

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Synthesis and photoresponse characteristics of single-crystalline Si nanowires (단일 Si 나노선 합성 및 광특성 연구)

  • Kim, Kyung-Hwan;Keem, Ki-Hyun;Kang, Jeong-Min;Yoon, Chang-Joon;Jeong, Dong-Young;Min, Byung-Don;Cho, Kyoung-Ah;Kim, Hyun-Suk;Kim, Sang-Sig
    • Proceedings of the KIEE Conference
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    • 2005.11a
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    • pp.81-83
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    • 2005
  • Photocurrent of a single-crystalline Si nanowire is investigated in this paper. Single-crystalline Si nanowires with amorphous $SiO_2$ shells were first synthesized from ball-milled SiO powders by thermal chemical vapor deposition, and then the amorphous $SiO_2$ shellswere etched out from the as-synthesized Si nanowires. For a single-crystalline Si nanowire, photocurrent-voltage curves taken in air at room temperature were non-linear, and rapid photoresponses were observed when the light was switched on and off. The photocurrent was not changed in intensity under the illumination. Photocurrent mechanism in the single-crystalline Si nanowire is discussed in this paper.

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Research of the driving characteristic in the electromagnetic launcher by switching circuit (스위칭 회로를 이용한 electromagnetic launcher의 동작특성에 관한 연구)

  • Han, Jae-Man;Joo, Sung-Joong;Jo, Ji-Ung;Lee, Man-Sung;Park, Dong-Suk;Park, Je-Uk;Byun, Jong-Hyuk;Kim, Dong-Suk;Park, Gwan-Soo
    • Proceedings of the KIEE Conference
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    • 2006.07c
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    • pp.1721-1722
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    • 2006
  • Electro-magnetic launcher(EML)는 전자기력을 이용하여 발사체를 추진시키는 장치이다. EML은 크게 레일건의 형태와 코일건의 형태로 구분되며, 본 논문에서는 코일건의 형태로 설계, 제작하였다. 코일건의 형태인 EML은 솔레노이드에 여자되는 전류에 의해서 발사체에 흡인력이 발생하여 추진, 가속되므로 솔레노이드의 최적형태를 설계하고, 이를 바탕으로 제작하여 EML의 스위칭 시간에 따른 속도를 측정하여, 여자전류의 스위칭 시간에 따른 동작특성을 해석, 실험하여 분석하였다.

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Electrical Conduction Properties of Synthetic Fluids (합성절연유의 전기전도특성)

  • 조경순;최봉철;이종필;이수원;신현택;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.294-297
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    • 1997
  • A study has been carried out electrical conduction properties of synthetic fluids No. 2 of KS class VII used for insulating and cooling the power device. BTA(Benzotrizole) as the streaming electrification suppressant additive is added to the oil, and the change of physical and electrical properties due to different BTA concentration is investgated. From the result of FTIR spectrum, it is confirmed that the absorpption peak in wavenumber 3400-3450[cm$\sub$-1/] is smaller and disappered by adding BTA to the oil. It is considered that the effective content of BTA is about 10[ppm] from the result of electrical conduction experiment.

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LC Aligning Capabilities of a Nematic Liquid Crystal on Homeotropic Polyimide Surface by New Ion-beam Irradiation

  • Ok, Chul-Ho;Kang, Dong-Hun;Lee, Kang-Min;Han, Jin-Woo;Kim, Byoung-Yong;Oh, Byeong-Yun;Kim, Young-Hwan;Hwang, Jeong-Yeon;Lee, Sang-Keuk;Han, Jeong-Min;Seo, Dae-Shik
    • Transactions on Electrical and Electronic Materials
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    • v.8 no.6
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    • pp.265-267
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    • 2007
  • The liquid crystal(LC) aligning capabilities of a nematic liquid crystal(NLC) on a homeotropic polyimide(PI) surface using a new ion-beam method were studied. Exposure ion-beam of $45^{\circ}$ incidence angle shows a good LC alignment of the NLC on the homeotropic PI surface. Also, on the homeotropic PI surface, the tilt angle of the NLC by exposure ion-beam of $45^{\circ}$ incidence angle had a tendency to decrease as increased ion-beam energy density. And, on the homeotropic PI surface, the alignment character of the NLC with respect to ion-beam energy was good at 1500 eV. And we achieved satisfactory result for EO character.

Development of BiPbAgSrCaCuO Superconductor used diffusion of dual layer and The growth mechanism process of superconducting phase (이중층 시료에서 확산을 이용한 BiPbAgSrCaCuO 초전도체 개발 및 초전도상 성장기구)

  • Choi, S.H.;Gang, H.G.;Yu, H.S.;Yu, J.J.;Choi, M.H.;Kim, M.K.;Choi, H.S.;Han, T.H.;Park, S.J.;Hwang, J.S.;Han, B.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1993.05a
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    • pp.22-27
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    • 1993
  • we prepared 70K new BiPbAgSrCaCuO superconductor used diffusion of dual layer which composed of SrCaCuO and BiPbAgCuO compound. This method is used permeation and diffusion on partial melting point of BiPbAgCuO compound. Samples were analyzed by means of X-ray diffraction analysis, Thermal analysis, critical temperature and scanning electron microscopy. It was found that the best results were obtained for spread volume (A:B=1:0.6) and sintring time 210hours.

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