• Title/Summary/Keyword: W-modification

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A PSpice Model for the Electrical Ballast of HID Lamps (전자식 안정기를 위한 HID Lamp 시뮬레이션 모델)

  • Chi, Y.K.;Kwon, W.M.;Kim, N.J.
    • Proceedings of the KIEE Conference
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    • 2002.04a
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    • pp.123-125
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    • 2002
  • To simulate the characteristics of an High-Intensity Discharge Lamp, this paper uses PSpice circuit model which have been developed from modification of the classical Cassie and Mayr equations. The model is for an High-Intensity Discharge Lamp and compatible to adopt high-frequency electric ballast. This model is correspond to some conditions between the simulated and experimental results.

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Temperature analysis of thick plate during welding (1) (후판 용접부 온도 분포 해석 1)

  • Choi, K.;Chang, R.W.;Eom, G.W.
    • Journal of Welding and Joining
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    • v.8 no.3
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    • pp.53-59
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    • 1990
  • Temperature distribution of thick plate during welding was investigated. Applied weldng process was shielded metal arc welding which was known as one of the most utilized processes in fabrication fields. Heating and cooling cycles were recorded by imploying high fidelity recorded and K-type thermocouple of 0.3mm in diameter. Both analytical and numerical calculations were preformed so as to verify the thermal cycle measurement. Results showed that the temperature of a welded points at given time could be predicted by the theoretical calculations. It was considered that methods could be applied to real structural components with slight modification.

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A Study on the UV Degradation characteristics of FRP by Plasma Surface Modification (플라즈마 표면개질에 따른 FRP의 자외선 열화 특성에 관한 연구)

  • Lim, K.B.;Lee, S.H.;You, D.H.;Hwang, M.W.;Lim, E.C.;Cho, G.S.;Lee, D.C.
    • Proceedings of the KIEE Conference
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    • 2003.07c
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    • pp.1544-1546
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    • 2003
  • In this study, composite materials were put to dry interfacial treatment by use of plasma technology. It has been presented that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system Pressure, 100 W of discharge power, and 3 minutes of discharge time. The decrease in surface potential of charged samples by corona discharge indicates that the amount of accumulated electrical charges reduces and the charges that have been injected lessen rapidly when the duration of UV irradiation increases. The surface resistivity and the tensile strength of plasma treated samples, a longer UV irradiation time resulted in decreased insulation.

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Design of Cooling System for Variable Speed 300kW PMSM (300kW 급 가변속 PMSM의 냉각시스템 설게)

  • Zhou, Guang-xu;Lee, Dong-Hee;Ahn, Jin-Woo;An, Young-Joo
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.923-924
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    • 2007
  • due to the modification of ventilation system for variable speed high efficiency PMSM, the ventilation structure is analyzed in this part. First, a cooling structure was proposed for the variable speed PMSM. Through the contrast result of whole stress and speed distribution in the cooling channel by fluid field, the fans setting fashion is confirmed. By the studying of cooling structure for improved PMSM, the position of the cooling hole in the rotor is optimized by the finite element method. At last, the thermal field distribution of the motor is calculated by FEM. The calculated thermal rise is in accord with measured value, which provides effective basement for the design and safety operation of PMSM.

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W Chemical Mechanical Polishing (CMP) Characteristics by oxidizer addition (산화제 첨가에 따른 W-CMP 특성)

  • Park, Chang-Jun;Seo, Yong-Jin;Lee, Kyoung-Jin;Jeong, So-Young;Kim, Chul-Bok;Kim, Sang-Yong;Lee, Woo-Sun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.46-49
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    • 2003
  • Chemical mechanical polishing (CMP) is an essential dielectric planarization in multilayer microelectronic device fabrication. In the CMP process it is necessary to minimize the extent of surface defect formation while maintaining good planarity and optimal material removal rates. The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on W passivation layer, in order to obtain higher removal rate (RR) and very low non-uniformity (NU%) during W-CMP process. In this paper, we compared the effects of oxidizer or W-CMP process with three different kind of oxidizers with 5% hydrogen peroxide such as $Fe(NO_3)_3$, $H_2O_2$, and $KIO_3$. The difference in removal rate and roughness of W in stable and unstable slurries are believed to caused by modification in the mechanical behavior of $Al_3O_3$ particles in presence of surfactant stabilizing the slurry.

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