• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.19-19
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• 2004

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1422-1424
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• 1998

This paper deals with the surface aging and electrical characteristics of EPDM specimen with cooling and heating cycle. Then dielectric loss and weight loss are measered to evaluate electrical properties of EPDM on bulk and surface The specimens which underwent aging cycle over 600 hr reveal severe erosion on EPDM surface

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.233-234
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• 2006

LNG is extremely cold, $-160^{\circ}C$ in its liquid state. When it vaporizes, returning to its natural state (re-vaporization), it cools its surroundings. This is cold energy. The manufacturing of liquid air is the first processes developed as the most effective utilization of LNG cold. In this paper, adopting the LNG cold process for manufacturing liquid air was developed and analysed. The result showed that as the higher air pressure and adapting nitrogen precooling, liquefaction rate and cumulative mass was increased.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.489-495
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• 2015

Forging is a manufacturing process involving the shaping of metal using localized compressive forces and the process of deforming metal into a predetermined shape using certain tools and press according to the temperature. Forging provides stronger metal parts than that possible by casting or machining. Conventional clutch jaw parts have been developed through cold forging and precision machining; however, fabrication of integral clutch jaw parts for farm machinery has not been reported yet. These parts were developed by applying a complex forging technology combining cold and hot forging. The integrated forming technology proposed in this study will be useful for reducing the lead-time for manufacturing, improving the accuracy of products, and eliminating the welding process.

• JOURNAL OF ELECTRICAL WORLD
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• s.263
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• pp.79-87
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• 1998

(1)코제너레이션이란 Co(공동의)와 Generation(발생)의 복합어로 이것을 시스템업한 것을 코제너레이션시스템(CGS)이라 한다. CGS는 전기와 열을 동시에 생산한다 해서 열전배합시스템이라고도 하며, 지금까지 대기에 방열하고 있던 엔진배열을 회수하여 발전에 이용함으로써 종합에너지효율을 75% 전후까지 높이는 시스템이다. 미쓰비시전기는 장기간에 걸친 전력계통기술, 발전$\cdot$냉열기술에 최신 일렉트로닉스기술을 결집하여 고신뢰성과 고효율을 실현하였다. (2)CGS에서 사용하는 엔진은 여러 조건에 따라 디젤엔진, 가스엔진, 가스터빈이 채택되는데 최근에는 배가스가 깨끗한 가스엔진, 가스터빈의 보급이 현저히 많아졌다. 또 CGS에서는 각종 NOx 저감기술이 개발되어 실용화되고 있어 디젤 엔진에서 300ppm, 가스엔진에서 150ppm, 가스터빈에서 100ppm정도까지 저감이 가능하다(어느 것이나 Nox 대책기는 0$\%$ $O_2$).(3)CGS의 도입 촉진을 위해 아래와 같은 전력회사와의 계통연계, 전기사업법 개정, 상용방재 겸용화 등 각종 규제완화가 실시되었다. -특고압수전에서 역조류가 있을 경우에 대비한 기술요건의 명확화 -1,000kW미만의 발전소는 공사계획 신고 불필요 -가스터빈발전소는 1,000kW미만, 내연력발전소는 모두 사용전검사가 원칙적으로 불필요 -도매공급사업에 관련된 참여허가의 철폐 -가스연료엔진도 상시방재 겸용화 가능

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.5
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• pp.680-686
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• 1998

In the adoption of a desalination system the most important factor is the cost of fresh water pro-duction. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$ When it is serviced however the LNG absorbs energy from a heat source and it is transformed to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energycan be utilized to produce fresh water by using a sea water freez-ing desalination system. in order to develop a sea water freezing desalination system and to estab-lish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water in a cooled circular tube to measure the freezing rate and to investigate the freezing heat-transfer characteristics. The experimental results provide a general understanding of sea water freezing behavior in a cooled circular tube.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.556-560
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• 2009

개별 대수층에 냉수와 온수를 저장하여 수자원과 냉난방 열원으로 활용하는 방안에 대한 평가를 지열-지하수 부정류 모델링을 통해 수행하였다. 저장 및 회수 가동 시간이 증가함에 따라서 각각의 대수층 내에 온열과 냉열이 축열되는 현상이 확인되었으며, 지하수 유동에 의해 축열된 수체가 지하수 흐름방향으로 이동하는 현상을 확인 하여 지하수 유동이 축열 정도를 결정하는 요인이 될 수 있음을 확인하였다. 설정된 모델에 대하여, 두 개의 개별 대수층 사이의 열 간섭은 거의 없는 것으로 나타났다. 주입과 양수의 가동 횟수가 증가되면, 대수층 축열 효과는 증대되는 것으로 나타났다. 열-지하수 모델링을 통한 온도 예측은 실제 냉난방의 효율성을 결정짓는 수온을 정량적으로 계산할 수 있는 유용한 기술로 평가됨과 더불어, 수자원의 지하 저장을 통해 효율적으로 물을 확보하고 관리할 수 있는 방안이 될 수 있을 것으로 기대된다.

• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.48-55
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• 1999

thermodynamic cycle analysis has been performed for the power generation systems to utilize the cold energy of liquefied natural gas (LNG). The power cycle used the air or water at room temperature as a heat source and the LNG at cryogenic temperature as a heat sink. Among manypossible configurations of the cycle. the open Rankine cycle. and the closed Brayton cycle, and the closed Rankine cycle are selected for the basic analysis because of their practical importance. The power output per unit mass of LNG has been analytically calculated for various design parameters such as the pressure ratio. the mass flow rate. the adiabatic efficiency. the heat exchanger effectiveness. or the working fluid. The optimal conditions for the parameters are presented to maximize the power output and the design considerations are discussed. It is concluded that the open Rankine cycle is the most recormmendable both in thermodynamic efficency and in practice.

• Solar Energy
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• v.18 no.3
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• pp.169-175
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• 1998

Metal hydrides can be used for the purpose of heat storage and transportation from the industrial complex which own recoverable waste heats to the neighboring cities by the medium of hydrogen. The properties of metal hydrides, some problems of heat transportation using metal hydrides, and the example of heat transportation system were discussed.

• Journal of Power System Engineering
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• v.11 no.1
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• pp.56-62
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• 2007

This paper represents the cold energy for liquefied nitrogen gas and cascade refrigerator. In this study, the vaporizer of liquefied nitrogen gas has the fin coil tube type with the dimension of inside diameter of 10mm and outside diameter of 12mm. Also, the total length of vaporizer is 20,000mm. The main experimental parameters are the mean velocity in duct and the supplied flow-rates of liquefied nitrogen gas. For the cascade refrigeration system, the refrigerants are ethane(R 170) in the high pressure stage and R 22 in the low pressure stage.