• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.213-214
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• 2001

This paper describes a power supply for a rapid pulse power charging system designed for charging a $0.35{\mu}F$ capacitor to 20kV in approximately 3ms. The power supply should be capable of recharging the load capacitor maximum 300 times within one second. This power supply is based on a series resonant 3-phase inverter followed by the step-up transformers. The experiments have been carried out at different repetition rates and charging voltages.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.135-137
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• 1994

In this paper, step response, speed, maximum frequency characteristics of 2-phase, 8-pole, HB type, prototype linear pulse motor(LPM) were investigated with the open loop control system(OLCS) being attached to the LPH. In this experiment, both 1-phase and 1-2 phase excitation types were adopted and microcomputer was used in deal with the data. The results point to some directions for the improvement of the open loop control system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05c
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• pp.53-56
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• 2004

This paper describes the method of position error reduction in Linear Pulse Motor (LPM). Though the micro step exiting method is applied, the vibration and position error caused by trust distortion from mechanism still remains. This paper presents the method for reduction of position error on moving the mover at whole cycle, by compensating a scale factor through real-time control of the PWM pulse width corresponding to exiting current command and absolute position error from linear encoder.

• 연구논문집
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• s.31
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• pp.89-99
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• 2001

This paper presents the modeling and analysis of dynamic characteristics of hydraulic snubber in electric power plant. The nonlinear state-space model of 14th order to describe the dynamics of the snubber was established by Simulink. The simulation results show that the hydraulic snubber reacts as like the conventional shock absolvers against the high pulse shock load. The snubber also shows the peculiar characteristics to the small step load, which temporarily lock the control valves up, however maintain same steady-state pressures of all internal chambers in the long run. Two case studies for the analysis of the snubber are addressed. Practical pulse testing method was also proposed to identify the frequency response of the snubber.

• Journal of Power Electronics
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• v.11 no.3
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• pp.375-380
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• 2011

A STATic synchronous COMpensator (STATCOM) is a shunt connected voltage source converter (VSC) based FACTS controller using Gate Turn Off (GTO) power semiconductor devices employed for reactive power control. The operation principal is similar to that of a synchronous condenser. A typical application of a STATCOM is voltage regulation at the midpoint of a long transmission line for the enhancement of power transfer capability and/or reactive power control at the load centre. This paper presents the modeling of STATCOM with twenty four pulse three level VSC and Type-1 controller to regulate the reactive current or the bus voltage. The performance is evaluated by transient simulation. It is observed that, the STATCOM shows excellent transient response to step change in the reactive current reference. While the eigenvalue analysis is based on D-Q model, the transient simulation is based on both D-Q and 3 phase models of STATCOM (which considers switching action of VSC).

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.192.1-192.1
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• 2013

본 연구는 기존의 Sputtering 방식에 Modulation 방식을 적용한 Modulated Sputtering System (MSS)에 관한 특성 관찰과 이를 이용한 박막 증착 및 분석에 관한 내용이다. MSS에 인가하는 전압은 pulse on 시간동안 타겟에 음의 전압이 인가되어 sputtering에 의한 박막이 증착되고, pulse off 시간동안에는 양의 전압을 인가하여 증착된 박막에 양이온을 입사시켜 에너지 전달에 의한 박막의 특성을 향상시키고 자한다. MSS에 인가되는 전압과 주파수, 그리고 펄스폭을 변화시키며 전압과 전류, 그리고 기판에 입사하는 이온에너지 특성을 관찰하였다. 또한 MSS를 이용하여 티타늄(Ti), 탄소(C), 알루미늄이 도핑된 산화아연(AZO) 박막을 증착하였다. 증착된 박막은 a-step, SEM, XRD, AFM, 4 point probe를 이용하여 박막의 두께, 결정성장면, 표면 거칠기, 비저항 등을 분석하였다. Ti 박막에서는 기판에 입사되는 양이온의 에너지가 증가함에 따라 결정 방위면이 (002)에서 (001)로 변화함을 확인하였고 탄소 박막과 AZO 박막의 경우에는 기판에 입사되는 양이온의 에너지 변화에 따라 박막의 전도도를 조절할 수 있음을 확인하였다.

• Journal of Life Science
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• v.10 no.2
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• pp.50-54
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• 2000

The RAD4 gene of Saccharomyces cerevisiae is essential for the incision step of UV-induced excision repair. A yeast RAD4 gene has been previously isolated by functional complementation. In order to identify the RAD4 homologous gene from fungus Coprinus cinereus, we have constructed cosmid libraries from electrophoretically separated chromosomes of the C. cinereus. The 13 C. cinereus chromosomes were resolved by pulse-field gel electrophoresis, hybridized with S. cerevisiae RAD4 DNA, and then isolated homologous C. cinereus chromosome. Here, we report the cloning and characterization of fungus C. cinereus homolog of yeast RAD4 gene. Southern blot analysis confirmed that C. cinereus contains the sequence homologous DNA to RAD4 gene and this gene exists as a single copy in C. cinereus genome. When total RNA isolated from C. cinereus cells was hybridized with the 3.4 kb BglII DNA fragment of the S. cerevisiae RAD4 gene, a 2.5 kb of transcript was detected. The isolated gene encodes a protein of 810 amino acids.

• Korean Journal of Optics and Photonics
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• v.2 no.4
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• pp.227-232
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• 1991

The possibility for the high intensity and energy possessing a short pulse in the HF chemical laser system which contained fluoride molecules (RF) was demonstrated theoretically through the numerical model simulation. The calculation was accomplished by assuming that the thermal branched chain mechanism of RF was occurred in the initiation step of $H_2+F_2$ chain reaction. Variations of the major chemicals and the temperature in the system were calculated as a function of time. An analysis was also performed to evaluate output pulse profile through parametric studies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.237-242
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• 1999

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the property of high-order pulses which are systematically obtained following their orders. The high-order pulses are easily derived from a modified PRS system model. But we make clear they are very useful to cover wider area and more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. This may be based on the fact that the spectra and bandwidths of the high-order pulses are beautifully related to their orders. first modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission which has any shape and FWHM, using the proposed model. In addition, by fixing the pulse range $\tau$=1(ps) and varying the order of the pulse from n:1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)-150(fs) FWHM's, which are widely used in fiber communications. As a one-step further, we derive PSD's of their pulse trains when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but also will be applied to any pioneering ultrashort pulse in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.177-183
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• 1999

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the property of Raised-cosine pulse which are systematically obtained following Class-2 PRS model. The high-order pulses are easily derived front a modified PRS system model as Class-1 PRS model. This may be based on the fact that the spectra and bandwidths of the high-order pulses are beautifully related to their orders. And we make clear they are very useful to cover wider area and more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. First modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission which has any shape and FWHM, using the proposed model. In addition, by fixing the pulse range $\tau$=1(ps) and varying the order of the pulse from n=1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)-100(fs) FWHM's, and width of FWHM in the Class-2 PRS model 50~100(fs) smaller than Class-1 PRS model. As a one-step further, we derive PSD's of their pulse trains when they are applied to Unipolar signaling scheme. These PSD's are derided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but also will to applied to any pioneering ultrashort pulse in the future.