• KIEAE Journal
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• 제2권4호
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• pp.65-72
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• 2002

In this study, the evaluation of environmental performance of the building energy system of domestic commercial sector was carried out. Based on the theory of linear programming model, we established an evaluation model satisfying object functions and constraint conditions. Employing the model, the evaluation of building energy system was performed under the consideration of cost and environmental constraint conditions. As an evaluation tool, MARKAL (MARKet Allocation) known as a market distribution model was employed. We analyzed scenarios of Case I (Base Scenarios) through Case IX established by the combination of the components of building energy system such as glazing, building skin, core, and heat source system. According to the results of the evaluation, highest contribution on the useful energy demand was obtained from the building energy system combined with solar heat source system, when the total amounts of $CO_2$ exhaust as an environmental constraint condition is assumed to be the level of 1995.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.141-143
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• 2007

Increasing demand of using low weight materials in recent automotive trends has been the challenge to develop a sound welding of aluminum alloys. A heat treatable AA6082-T6 and a non-heat treatable AA5083-0 aluminum alloys were joined in this study. Investigations revealed that about 60 UTS will be reduced due to welding process. Fracture happened in the interface between fusion zone and base metal of top specimen where penetration is shallow. Therefore, lower welding torch angle produced the better strength which allows deeper penetration to the top specimen. PWHT at $560^{\circ}C$ for 2 hours can be used to return the original UTS of the specimens.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.61-66
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• 1987

The metals has been used to the electric motor frame and brackets. The purpose of this project is to substitute engineering plastic doter frame for metal because of the demand for small size and environmental reliability. As a result of considering of mechanical strength, heat and injection characteristic of engineering plastics. PBT GF 30 has been selected as the material of electric motor frame including brackets. Design of the frame has been carried out on enough consideration of mechanical strength, heat-resisting and endurance. For the prevention of lower efficiency, the length of airgap between stator and rotor is reduced and for the reduction of vibration, slot combination is changed and the length of stator is increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.553-555
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• 1995

This paper presents the optimal short-term operation scheduling by using on cogeneration systems connected with auxiliary equipments. Simulation is performed in case of the bottomming cycle which generates the demand heat preferentially. Heat storage tank, electricity charger, auxiliary boiler and independent generator are considered as auxiliary equipments connected to cogeneration systems. The results of simulation show the auxiliary equipments can be effeciently operated in case of the bottomming cycle by modeling proposed in this paper. The effectiveness of operation scheduling gained by application of fuzzy theory is evaluated by detailed comparison and investigation of the simulation results.

• 한국진공학회지
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• 제8권3B호
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• pp.257-261
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• 1999

The claw pump, one of oil-less dry pumps developed to solve problems found in vacuum systems pumped by oil-sealed rotary pumps, has been widely used separately or as a part of compound structure with a roots pump. The claw pump has some merits such as a high pumping speed, a high compression ratio, and relatively little heat generation. The high compression ratio of the claw pump is compression ratio, and relatively little heat generation. The high compression ratio of the claw pump is based on efficient sweeping action of the special type rotor and an intrinsic self-valving mechanism. The contour of the rotor with claw-type blade is designed basically to make two rotors revolve smoothly without touching with each other, and related dimensions are determined by required pumping speed, compression ratio, power demand and diameter of the rotor axis. In this paper the procedure of designing the rotor of the claw pump is described and factors influencing the pump performance are analyzed.

• 열처리공학회지
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• 제36권6호
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• pp.412-421
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• 2023

As the demand for mechatronic systems and high performance increases in the machinery industry, the importance of improving friction characteristics is emphasized. During relative movement of objects, friction and wear occur on two surfaces in contact, and various methods are being designed to increase the lifespan and energy efficiency of machines. The energy increase effect using lubricants is a well-known method. In this study, a micro-sized rectangular grid pattern was produced by applying a precise micro-pattern photo lithography process. Rectangular grid patterns of the same shape and friction behavior according to the size of the pattern were produced in convex and concave shapes, and the tribological characteristics of each were analyzed.

• 에너지공학
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• 제22권2호
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• pp.211-225
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• 2013

본 연구에서는 서로 다른 위도의 도시 유형별로 주택과 건물 구성비를 가진 3지역을 선정하여 대상 지역별로 2008년 1년간(1.1~12.31)의 실제 운전실적을 이용하여 지역난방 사용자의 일일 및 연간 열소비 패턴을 분석하고, 지역별 상호 차이점을 파악하기 위하여 주택과 건물의 열소비 패턴을 비교 분석하였다. 특히 본 연구에서는 실제 주택 및 건물 지역난방 사용자가 사용한 열소비 패턴을 매시간대별로 파악하고, 연결 열부하(난방면적 ${\times}$ 단위열부하 : 시설용량과 지역난방 배관망의 설계기준이 되는 열부하로 난방면적에 용도별 단위열부하를 곱하여 산출[Gcal/h])와의 관계를 분석하여 일일, 연간 및 최대 부하율 결과값을 도출함으로써 주택 및 건물 지역난방 사용자 비율에 따른 최적의 열원시설 용량산정이 가능케 하고 수요개발(해당 시설용량으로 열공급이 가능한 지역난방 사용자의 범위로 각 사용자기계실의 연결열부하 합과 같음.)단계에서의 정확한 방향을 제시할 수 있는 근거를 도출하였다.

• 태양에너지
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• 제18권3호
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• pp.71-80
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• 1998

In thermal energy storage system, energy collected from many types of heat source is stored in a storage tank and then supply to load for demand. Lately, practical use of thermal energy storage system and attention to essential use of energy have been increased. From this point of view, especially, a study about the energy extraction process from a storage tank is necessary. So in this study, useful rate of hot water and hot water extraction efficiency was analysed respect to dynamic and geometric parameters dominating the hot water extraction process.

• 반도체디스플레이기술학회지
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• 제1권1호
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• pp.41-45
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• 2002

In modem manufacturing, new applations and technologies demand smaller, and functional devices to replace large systems. As miniaturization becomes a necessity, many companies are interested in small pumps for use in creating ultra-high vacuum, but past efforts to develop such systems have failed due to problems with vibration, stress, heat and power consumption. This paper shows analysis-based design techniques for high vacuum turbomolecular pump by finite element analysis.

• Journal of the Korean Wood Science and Technology
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• 제41권1호
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• pp.77-86
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• 2013

본 연구는 목조주택의 건물에너지 성능을 평가하고 개선하기 위해 수행되었다. 목조주택의 에너지 요구량을 산정하기 위하여 CE3 (Construction Energy Efficiency Evaluation) 웹기반 소프트웨어를 사용하였고 그 결과 대상 주택의 연간 난방에너지 요구량은 바닥면적 1 $m^2$당 160 kWh로 계산되었다. 난방에너지 요구량을 줄이기 위해 다음 4가지의 에너지 절감방법을 채택하였다; a) 건물형태의 단순화, b) 창호면적의 축소, c) 고성능 창호의 적용, d) 폐열회수환기장치의 적용. 열관류율 1 $W/m^2{\cdot}K$의 고성능창호로 교체할 경우 대상 주택의 난방에너지 요구량은 80 $kWh/m^2{\cdot}a$로 감소하였다. 4가지 방법을 조합하여 적용하면 고성능창호와 폐열회수환기장치를 함께 적용하였을 때 난방에너지 요구량은 34.5 $kWh/m^2{\cdot}a$로 감소하여 가장 우수한 성능을 나타냈다.