• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.549-550
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• 2011

본 논문에서는 단일 스위치 배전압 방식의 단상 PFC 회로의 제어기 설계방법을 제안한다. 이 PFC 회로는 저가형 이중변환방식 단상 UPS의 AC-DC 변환부에 사용되고는 있으나, 전압 제어기와 전류 제어기의 설계방법과 입력 역률 보상 및 입력 전류 고조파 억제 성능에 대한 연구결과가 알려지지 않았다. 제안된 방법으로 설계된 제어기들의 제어 성능과 입력 역률 및 입력 전류의 THD를 시뮬레이션을 통해서 검증하였다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.398-399
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• 2011

본 논문에서는 단일 스위치 배전압 방식의 단상 PFC 회로의 제어기법들에 대해 기술한다. 이 PFC 회로는 저가형 이중변환방식 단상 UPS의 AC-DC 변환부에 사용할 수 있으나, 입력전류의 제어기법에 대한 연구 결과가 알려지지 않았다. 제안된 전류 제어기법들의 입력 전류 제어 성능, 입력 역률, 입력 전류의 THD를 시뮬레이션과 실험을 통해서 비교 검증하였다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.551-552
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• 2011

본 논문에서는 단상 이중변환 UPS의 AC-DC 변환부를 위한 단일 스위치 배전압 방식의 단상 PFC 회로의 동작특성에 대해 기술한다. 이 PFC 회로는 적은 개수의 전력용 반도체를 쓰기 때문에 비용 절감에 도움이 된다. 동작 모드에 따른 회로 각부의 전압, 전류 파형과 출력 전압 제어, 입력 역률 보상, 입력 전류 제어의 THD 억제 성능을 시뮬레이션과 실험을 통해 보였다.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.968-973
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• 2007

This paper presents an electromagnetic design for the magneto-rheological fluid valve. The MR valve can control high-level fluid power without moving parts, due to the apparent viscosity controllability of the MR fluid in magnetic fields. In order to improve the static characteristic of the MR valve, the length of the flux path is decreased by removing the unnecessary bulk of the yoke. Then, in order to improve the dynamic and hysteretic characteristics, the magnetic reluctance of the ferromagnetic material is increased by minimizing the cross sectional area through which the flux passes. Two MR valves, one is a conventional type valve and the other is the proposed one, were fabricated and performance evaluation is experimentally achieved through the comparison study using by-pass damper system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.40-43
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• 1995

In this paper, structual, optical and electrical properties of CdZnS thin films prepared by electron beam evaporation method were studied. The crysta1 structure of CdZnS films deposited was hexagonal type with preferential orientation of the (002) plane parallel to the substrate. The results of optical transmittance of the CdZnS film show that absorption edge is shifted to ZnS and optical bandgap was larger wish increasing ZnS content. The resistivity of the CdZnS film is decreasing with increasing ZnS content and mininum for 20 mole%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.908-911
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• 2002

Recently deep interests and attraction have been paid on the generation of ozone, which is widely used to remove bed smell and to clear water. In this paper the silent discharge and ozone generation characteristics of various typed discharge chambers were investigated experimentally. Dielectric of $Al_2O_3$ was embedded in the cylindrical type of discharge chamber to improve the ozone generation rate and to stabilize the silent discharge mode of operation. Discharge current and ozone concentration depend strongly on the applied voltage and frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1050-1053
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• 2002

This paper presents metal structure that is fabricated using UV-LIGA process with PMER N-CA3000. In order to fabricate metal structure with high aspect ratio, the systematic optimization method was adopted and then the structure of $36{\mu}m$ thick mold with aspect ratio 7:1 (trench) and $32{\mu}m$ thick nickel structure was obtained. This structure is applied to the fabrication of optical switch.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.991-996
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• 2002

Transient magnetic diffusion process in a melt-cast BSCCO-2212 tube is analyzed by an analytical method. The transient diffusion partial differential equation is transformed into an ordinary differential equation by integral method. The penetration depth of magnetic field into a superconducting tube is obtained by solving the differential equation numerically. The results show that the penetration depth as a function of time which is somewhat different from the results by Bean's critical state model. The reason of the difference between the present results and that of Bean's model is discussed and compared in this paper.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1304-1307
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• 2004

실제 Cu CMP 공정이 진행되는 동안 연마입자의 응집현상을 관찰하긴 어렵다. 따라서 본 연구에서는 인위적으로 첨가한 large particle들이 공정 중에 발생하는 응집입자라 가정하고 각 공정에 따른 연마속도와 friction force를 측정하여 large particle을 첨가하지 않은 슬러리와 비교 평가해보았다. large particle을 첨가한 슬러리의 경우에 각 공정변수에 따라 연마속도와 friction force가 작아짐을 관찰하였다. 즉, 슬러리 내에 응집현상이 발생하게 된다면 large particle이 연마의 방해 인자로 나타남을 관찰 할 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.207-211
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• 2000

Deep Interests have been paid on the application of non-thermal plasma technique to solve the environmental pollution problems. $CO_2$ is one of the severe pollutants which cause the acid rain and global warming. In this study, in order to improve the conversion efficiency of $CO_2$, the streamer corona discharge plasma and barrier discharge plasma reactors were made, and the conversion characteristics of $CO_2$ by the corona discharge plasma and some discharge characteristics of these discharge chambers are studied experimentally.