• 에너지공학
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• 제9권2호
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• pp.95-101
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• 2000

The purpose of this study is to find plant utilities capacity for economical operation of combined heat & power by reducing energy expenditure. Using a numerical simulation program CHPSIM, a comparative analysis of additional heat expenditure (AHE) of combined heat & power plant in relation to size of district heating has been performed within the comparison of the difference capacity of gas turbine and steam turbine . As a results, if a 105.2MW gas turbine (exhaust gas temp ; 540$^{\circ}C$) installed in CHP plant can reduced 17-18% yearly the AHE than 75MW gas turbine (520$^{\circ}C$) installed. If a 130-150MW gas turbine (560-580$^{\circ}C$) installed, can reduced 34.7-35.8% of the yearly AHE.

• 한국인쇄학회지
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• 제6권1호
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• pp.59-66
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• 1988

One of the rising problems in the field of environmental engineering is the eutrophic phenomenon which appears in the closed water basin. This study is the elimination orthophosphate by adsorption, which is indispensible nutritive element for eutrophication Ziriconium(IV) oxide hydrate-activatedcarbon complex. which has excellent adsorptivity for orthophosphate and can easily be reused after desorption process has been made and used as adsorbents. The main purpose of this study is to obtain intraparticle diffusivity which is basic data for the design of adsorption operation the experimental results were as follows. 1. Optimum condition which gave maxinum adsorption of orthophosphate was ph5 2. Equilibrium adsorption showed good consistency with Freundlich type. q=10.80C1/2.08 3. Pore diffusivity and surface diffusivity obtained the kinetic experiment of batch adsorption were respectivity 5.38 and 2.06 ($\textrm{cm}^2$/sec)

• 대한기계학회논문집
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• 제17권8호
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• pp.2099-2109
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• 1993

A gas-fired 4RT absorption heat pump was designed as an air-conditioner for domestic use during the summer. The absorption heat pump is air-cooled. double-effect, $LiBr-H_{2}O$ system with parallel flow type. The performance of the absorption heat pump in the cooling mode of operation was investigated through cycle modeling and simulation to obtain the system characteristics with parameter changes. System parameters considered in this analysis were the inlet temperature of cooling air to the absorber, the working solution concentrations, the ratio of the amount of the weak solution from the absorber, and the LTD's of each heat exchange component. The optimum designs and operating conditions were determined based on the operating constraints and the coefficient of performance.

• 한국정밀공학회지
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• 제15권12호
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• pp.106-112
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• 1998

A major problem in automation of turning operations is the difficulty in obtaining a sufficient and reliable chip control. The chip should be detected in order to provide a optimum chip control for unmanned turning operation. Using the difference of energy radiated from the chip, chip Patterns are estimated using pyrometer. From the initial output from the pyrometer, chips are identified according to the backpropagation algorithm developed in the research. The learning system developed in this work can be applied in real-time control of turning process with minor modification in drive system.

• 전기학회논문지P
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• 제60권4호
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• pp.253-256
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• 2011

LEDs have small size, long lifespan, high reliability, low power consumption and high color efficiency. Using such a characteristics, LED Back Light Unit has been studying actively. This paper proposes LED driver to minimize power consumption due to LED forward voltage($V_F$) difference and temperature rising. Compared to conventional LED driver, the proposed driver have excellent stability, brief structure and linear output voltage of DC-DC boost converter. Proposed LED Driver circuit was designed using 0.35um CMOS technology. And its operation was verified through simulation.

• 전기학회논문지
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• 제61권10호
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• pp.1513-1517
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• 2012

As demands for green industry increase, this paper proposes a power control technique that can substitute pre -existing CCFL(Cold Cathode Fluorescent Lamp) and optimize power consumption of LED BLU. This technique is designing LED driver circuit that make a DC-DC output voltage(VLED) to have a linear control function for a supply voltage of LED string. The proposed LED driver have an advantage that can increase or decrease a DC-DC output voltage compared with conventional LED driver. The designed LED driver circuit was designed using 0.35um CMOS technology. And its operation was verified through simulation.

• 전기학회논문지
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• 제56권3호
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• pp.451-456
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• 2007

This paper presents a problem that reconfigure distribution power system using branch exchange method. Optimal reconfiguration problem calculates line loss, voltage condition about system states of all situations that become different according to line On/off status, and search for optimum composition of these. However, result is difficult to be calculated fast. Because radiated operation condition of system is satisfied using many connection and sectionalize switches in the distribution power system. Therefore, in this paper, optimization method for reducing system total loss and satisfying operating condition of radial and constraints condition of voltage is proposed using the fastest branch exchange. And optimal solution at branch exchange algorithm can be wrong estimated to local optimal solution according to initial operating state. Considering this particular, an initial operating point algorithm is added and this paper showed that optimal solution arrives at global optimal solution.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.548-551
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• 2000

The battery charger for high speed trail car is very important power source for the purpose of safty and system stability. it provides control power of VVVF, CVCF, DC/DC converter and inverter for traction motor. This paper included power circuit of the ZVZCS type battery charger for high speed trail car and battery included power circuit of the ZVZCS type battery charger for high speed trail car and inverter for traction motor. This paper included power circuit of the ZVZCS type battery charger for high speed trail car an battery charging algorithm. Also the optimum parallel operation of 50Kw battery charger for high speed trail car and charging control method of Ni-Cd battery illustrates validity and effectiveness through the experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1136-1141
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• 1992

This paper proposes a control technique to obtain high frequency quasi sinusoidal DC-Link waveform permitting zero-voltage-switching(ZVS). This operation results in reduction of commutation stress and switching losses in the power devices because they cause no switching loss in principle. But in existing control methods, the resonant capacitor voltage is not frequently made of zero-cross oscillation. We propose an optimum control stratege which can sustain oscillation and keep the capacitor voltage at an allowable level. Some experimental results are included to confirm the validity of the analytical results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1130_1131
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• 2009

현재까지 국내 PV시장은 신재생에너지 개발 이용 보급 촉진법을 통해서 태양광발전시스템의 이용 보급의 확대를 목표로 하고 있지만 이에 따른 해결해야할 기술적인 문제점들이 많다. 즉, PV시스템의 성능특성 평가분석은 발전성능에 중대한 영향을 미치는 주요 발생손실을 평가.진단함으로서 손실저감을 통한 시스템의 성능개선, 최적절계, 사후운영관리 및 유지점검 등의 응용기술을 개발하는데 있다. 이러한 기술개발을 위해서는 입력인 태양에너지로부터 PV어레이의 직류출력에서 시스템의 교류출력까지의 성능 및 발생손실에 대해서 정량적인 값으로 나타낼 필요가 있다. 본 논문에서는 태양광발전 설비의 효율에 관한 파라미터인 위도와 경도, 온도 및 일사량, 시스템 구성요소에 대한 세부적인 기술검토와 태양광발전시스템의 효율을 개선시킬 수 있는 파라미터에 접근하기 위해 정확한 시스템의 운전특성을 분석 하고자 한다.