• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.589-592
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• 2001

In this paper, Electronic ballast for multiple fluorescent lamps based on the use of ferrite beads are presented. The use of this system in place of the conventional electromagnetic ballast results in lower power consumption and reduced maintenance cost, because the electronic system has higher efficiency and longer lamp lifetime than the electromagnetic ballast. In comparison with the conventional electronic ballast. The proposed system presents a significant reduction of cost. This reduction becomes were meaningful with the growing of the lamp number. The description of the lighting system, We show that the proposed model can be applied to multiple lamps electronic ballast by simulation processes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.439-440
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• 2006

This paper presents precise measurement system for the lifetime of OLED. The proposed system collects the data for using voltage drop across the OLED Panels, and then the computer program makes an analysis of the data. In this process of measurement, the current across OLED material must be amplified because the current is very small. However, amplifying the current causes the amplification of noise. Therefore, the proposed system measures the current using an algorithm which minimizes the noise.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2089-2091
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• 2000

Pulsed power systems consist of a capacitor bank, an isolated high-voltage charging power-supply, high-current bus-work for charging and discharging and a control system. In such pulsed power systems, the operating-lifetime of the capacitors is closely dependent on the voltage reversal. Hence, most capacitor-discharging systems includes crowbar circuits. The crowbar circuit prevents the capacitor recharging with reverse voltage. Usually it consists of crowbar resistors and high pulse-current diode-stacks connected in series. The requirements for the diode-stacks are fast-recovery time and high-voltage and large-current ratings, which results in the high cost of the pulsed-power system. This paper presents a protection scheme of a charging and discharging system of a 500kJ capacitor bank using a low-cost crowbar circuit and safety-fuses.

• 한국태양에너지학회 논문집
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• 제33권5호
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• pp.18-23
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• 2013

This paper presents a simple but valid loss calculation method of grid-connected photovoltaic system based on normalized yield model. The proposed method can be represented as a quantitative value for five losses and performance of grid-connected photovoltaic system with three years monitored data. These results will indicate that it is useful to investigate various loss factors causing the performance obstruction, enhance the lifetime yield for changing meteorological conditions, and determine the optimal design and performance improvement of grid-connected photovoltaic system.

• International Journal of Reliability and Applications
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• 제11권1호
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• pp.1-16
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• 2010

In this paper we will discuss the stochastic analysis of a three state semi-Markov reliability model. Maximum likelihood procedure will be used to obtain the estimators of the parameters included in this reliability model. Based on the assumption that the lifetime and repair time of the system units are generalized linear failure rate random variables, the reliability function of this system is obtained. Also, the distribution of the first passage time of this system will be derived. Some important special cases are discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.589-592
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• 2001

In this paper, Electronic ballast for multiple fluorescent lamps based on the use of ferrite beads are presented. The use of this system in place of the conventional electromagnetic ballast results in lower power consumption and reduced maintenance cost, because the electronic system has higher efficiency and longer lamp lifetime than the electromagnetic ballast. In comparison with the conventional electronic ballast. The proposed system presents a significant reduction of cost. This reduction becomes were meaningful with the growing of the lamp number. The description of the lighting system, We show that the proposed model can be applied to multiple lamps electronic ballast by simulation processes.

• Bulletin of the Korean Chemical Society
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• 제9권2호
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• pp.84-87
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• 1988

The Photophysical and photochemical properties of Ruthenium bipyridine with two long hydrocarbon chains, $[Ru(bipy)_2(dhbipy)]^{2+}$ and transient phenothiazine derivative cation radical $(PTD^+)$ in the cationic vesicle were studied. Transient absorption spectra of cation radical of phenothiazine derivative in the vesicle system containing the $Ru^{2+}$ complex, $[Ru(bipy)_2(dhbipy)]^{2+}$, (1) as sensitizer and phenothiazine derivative as electron donor was observed by XeCl excimer laser photolysis system. Thus the excited ruthenium complex would be quenched by phenothiazine derivative(PTD) reductively in the vesicle system. The quenching rate constant($K_Q$) of $Ru^{2+}$ with two long hydrocarbon chains in the vesicle by PTD was $9.6{\times}10^8M^{-1}S^{-1}$. The absorption decay kinetics showed that lifetime of phenothiazine derivative cation radical is a value in the 4-8m sec range.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.430-430
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• 2008

Using multi plasma enhanced chemical vapor deposition system (Multi-PECVD), p-a-Si:H deposition layer as a $p^+$ region which was annealed by laser (Q-switched fiber laser, $\lambda$ = 1064 nm) on an n-type single crystalline Si (100) plane circle wafer was prepared as new doping method for single crystalline interdigitated back contact (IBC) solar cells. As lots of earlier studies implemented, most cases dealt with the excimer (excited dimer) laserannealing or crystallization of boron with the ultraviolet wavelength range and $10^{-9}$ sec pulse duration. In this study, the Q-switched fiber laser which has higher power, longer wavelength of infrared range ($\lambda$ = 1064 nm) and longer pulse duration of $10^{-8}$ sec than excimer laser was introduced for uniformly deposited p-a-Si:H layer to be annealed and to make sheet resistance expectable as an important process for IBC solar cell $p^+$ layer on a polished n-type Si circle wafer. A $525{\mu}m$ thick n-type Si semiconductor circle wafer of (100) plane which was dipped in a buffered hydrofluoric acid solution for 30 seconds was mounted on the Multi-PECVD system for p-a-Si:H deposition layer with the ratio of $SiH_4:H_2:B_2H_6$ = 30:120:30, at $200^{\circ}C$, 50 W power, 0.2 Torr pressure for 20 minutes. 15 mm $\times$ 15 mm size laser cut samples were annealed by fiber laser with different sets of power levels and frequencies. By comparing the results of lifetime measurement and sheet resistance relation, the laser condition set of 50 mm/s of mark speed, 160 kHz of period, 21 % of power level with continuous wave mode of scanner lens showed the features of small difference of lifetime and lowering sheet resistance than before the fiber laser treatment with not much surface damages. Diode level device was made to confirm these experimental results by measuring C-V, I-V characteristics. Uniform and expectable boron doped layer can play an important role to predict the efficiency during the fabricating process of IBC solar cells.

• 신재생에너지
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• 제2권4호
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• pp.86-92
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• 2006

This paper analyses the economics of 50kW PV system installed in Tibet and using domestic technology. We show that this system can be expanded to very large-scale photovoltaic power generation [VLS-PV] system successfully. Based on this result, we conduct the economic analysis of 100MW VLS-PV system designed assuming that it will be installed from 2008 to 2017 in Tibet. In this analysis, future price of PV module and system are estimated based on the methodology of experience curve. In 50kW PV system, the generation cost is calculated at 567.2 won/kWh and this is lower than the one of domestic PV system. In future 100MW VLS-PV system. the generation cost is calculated at 305.4 won/kWh by declining system price. If the lifetime and efficiency of the system goes up, due to future technological improvements, the generation cost can be lowered. Moreover, under the environmental and political effect, VLS-PV system can be as competitive as the conventional energy within 20 years.

• 마이크로전자및패키징학회지
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• 제23권2호
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• pp.37-42
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• 2016

전력가격의 상승으로 데이터센터의 운영비 부담이 늘어나는 가운데, 슈퍼컴퓨터에 저전력 프로세서를 사용하여 데이터센터의 전력소모를 감소시키는 연구가 활발하다. 일반적으로 모바일 기기 등의 운용환경을 기준으로 신뢰성 평가가 이루어지는 저전력 프로세서를 슈퍼컴퓨터에 사용하는 경우 상대적으로 가혹한 운용환경으로 인해 물리적, 기계적 신뢰성 문제가 발생할 수 있다. 이 논문은 슈퍼컴퓨터 운용 환경을 바탕으로 저전력 프로세서 패키지의 수명을 평가하였다. 먼저 문헌조사, 고장모드 및 치명도 분석을 통해 저전력 프로세서 패키지의 주요 고장원인으로 온도 사이클을 선정하였다. 부하-온도 관계를 확인하기 위해 단계적인 부하를 가하며 프로세서의 온도를 측정하였다. 가장 보수적인 운용조건을 가정하고 온도 사이클에 관련된 고장물리 모델을 이용한 결과 저전력 프로세서 패키지의 기대수명은 약 3년 이하로 예측되었다. 실험 결과를 바탕으로 저전력 프로세서 패키지의 기대수명을 향상하는 방법을 제시하였다.