• 한국해양공학회지
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• 제10권1호
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• pp.47-52
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• 1996

This paper deals with a study on improvement of long-time creep life prediction of steam turbine rotor steels by using initial strain method as a new approach at high temperatures of 500 to 70$0^{\circ}C$ . The main result shows that the inital strain method could be reliably utilized to predict and evaluate the long-time creep life as creep rupture strength and that the predicting equation for long-time creep life under a certain creep stress at a certain high temperature could be empirically derived out from each initial instantaneous strain measured.

• 한국식품과학회지
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• 제22권3호
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• pp.261-265
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• 1990

두충엽의 휘발성 성분을 SDE 장치로 추출한 후 GC 및 GC/MS에 의해서 비교 분석하였다. 확인된 성분은 35개 성분이며 alcohol류 7종, aldehyde류 3종, ketone류 4종, ester류 2종. hydrocarbon류 18종, phenol 1종이 확인되었다. 이 중에서 가장 많이 함유된 성분은 2-ethyl furyl acrolein으로 추정되었는데 전체 휘발성 성분의 31.4%를 차지하였다.

• 한국유체기계학회 논문집
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• 제16권6호
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• pp.26-31
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• 2013

Last blades of low-pressure turbine in nuclear power plant are the highly damaged part and always suffered from different types of loadings leading to various stress components, stresses due to centrifugal force and steam flow loading. Especially, centrifugal stress generated by turbine rotation is one of the main problems and more significant than other stresses as they have the greatest effect on total stress. Therefore, this study was performed to obtain the important information for estimation model development of the blade centrifugal stress level and distribution.

• 설비공학논문집
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• 제18권12호
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• pp.992-998
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• 2006

This study is to optimize design parameters for waste heat recovery boiler with water tube and three drum. The design optimization considered here is to find the most economic dimension of the boiler considered which results in a minimum cost in producing a unit amount of steam per given period of operation. For this purpose, optimize design have to determine what are the main parameters of affecting the total cost of producing a unit amount of steam which is comprised of manufacturing cost of the boiler, operating cost of the fan etc.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2284-2289
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• 1998

The Rotor Stress Indicator is an integrated system of hardware and program components which has been designed to read an assortment of turbine temperature and speed input devices, perform an analysis of the temperature induced stresses and output pertinent temperature and stress information to guide the turbine operator during turbine prewarming, start-ups, load changes, and shut-downs. The purpose of the RSI is to provide guidance to the plant operator during startup, shutdown, loading, and unloading of the turbine. Since the stresses are a function of the temperature changes to which the turbine is exposed, the RSI also provides guidance for operation of the boiler main steam and reheat steam temperatures as they affect the rotor stresses. This may permit more efficient overall boiler turbine start-ups. In this paper, new rotor stress analysis algorithm for RSI is introduced and compared with present system which has been used in thermal power plant.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.115-121
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• 2001

The wear test has been performed to evaluate the wear mechanism of steam generator (SG) tube materials against ferritic stainless steel in water environment. The wear rates of SG tube materials depend on the change of mechanical properties between contact surfaces during wear test. From the subsurface hardness test, Inconel 690 is more work-hardened than Inconel 600 even though these materials have similar hardness values before the wear test. Main cause is due to the difference of stacking fault energy with the chromium content. In water environment, wear mechanism is closely related with the continuous formation and fracture of deformation layers at the contact surfaces.

• 한국연초학회지
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• 제23권1호
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• pp.65-70
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• 2001

In order to compare the extraction patterns of main components from the raw material between the extraction methods, the aerial parts (dried stem, leaves, and flowers) of Agastache rugosa were extracted by SDE simultaneous steam distillation & extraction) and SFE (supercritical fluid extraction). Volatile components of essential oil and extract were identified by GC and GC-MSD. The contents of essential oil extracted by SDE were 0.49% in aerial part of Agastache rugosa on dry basis. Major components were methyl chavicol(27.2%), isomenthone(24.6%), hexadecanoic acid(13.0%). menthone (5.5%) among 32 kinds of components confirmed in essential oil. On the other hand, the contents of SFE extracts revealed 3.21% on dry basis, 6 times higher than those of SDE. Major components were isomenthone(15.3%), hexadecanoic acid(13.7%), methyl chavicol(12.6%), benzoic acid(3.8%) among 33 kinds of components identified in extract.

• Nuclear Engineering and Technology
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• 제34권2호
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• pp.132-141
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• 2002

The effects of microstructure on fretting wear were investigated in Inconel 690 tube. The microstructure observation indicated that the solution annealing temperature and time affected the grain size of the Inconel 690 tubes. The carbide morphology, along grain boundaries, was mainly affected by thermal treatment time and temperature. The wear test results showed that specimens with larger grain size and with coarse carbides along grain boundaries had better wear resistance. Cracks were found in specimens with carbides along the grain boundary, while few cracks were found in carbide free specimens. It seemed that the carbides on grain boundary assisted crack formation and propagation in carbide containing specimens. On the other hand, the micro-hardness of specimen did not have a major role in fretting wear. It could be inferred from the SEM images of worn surfaces that the main wear mechanism of carbide containing specimen was delamination, while that of carbide free specimen was abrasion.

• 대한기계학회논문집B
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• 제34권4호
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• pp.341-347
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• 2010

본 연구에서는 부탄 개질기 운전조건에 따른 SOFC 시스템 효율을 모델링을 통해 분석하였다. SOFC 시스템은 크게 개질기, SOFC, 폐열 회수 장치로 구성하였다. 탄화수소 개질 반응으로 선택한 수증기 개질 반응은 흡열반응인 데에 반해 SOFC 에서 일어나는 전기화학반응은 발열반응이다. 따라서 시스템의 열관리 방법에 따라 효율이 크게 달라진다. 세부적으로 수증기 개질 반응은 운전 온도에 따라 수증기 개질 반응과 예개질 반응으로 분류되는데, 해석 결과 예개질 반응을 적용한 SOFC 시스템의 경우 더 높은 효율을 나타내었다. 시스템의 효율은 SOFC 온도 유지를 위한 열량과 온수로 회수되는 열량에 따라 달라지는데, 예개질 반응을 적용할 경우, 열관리가 더욱 효율적이어서 높은 효율을 나타내는 것으로 분석되었다.

• 공업화학
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• 제26권6호
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• pp.648-658
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• 2015

수증기 증류법을 이용하여 잣나무의 손상 없이 잣송이 부산물로부터 피톤치드 성분의 대량 추출 가능성을 조사하였다. 또한 수증기 증류법에 의해 얻어진 잣나무 피톤치드 oil을 대상으로 column chromatography법에 의한 피톤치드의 구성 성분의 분리 가능성을 타진하였다. 잣송이 부산물로부터 물 수증기 증류법과 수증기 증류법에 의해 피톤치드의 대량생산이 가능하며, 수증기 증류법의 경우가 물-수증기 증류법의 경우에 비해 수율이 2배가량 높을 정도로 효과적이었다. 수증기 증류법의 경우 $100^{\circ}C$, 30 min간 증류 시 잣나무 피톤치드 oil의 수율이 최고점이 얻어졌다. 얻어지는 잣나무 피톤치드 oil의 주성분은 ${\alpha}$-pinene, ${\beta}$-pinene, D-limonene ${\beta}$-myrcene 및 3-carene 등 12가지 이상의 성분으로 이루어지고 있음을 확인하였다. 또한 수용성의 성분이 함유되어 있는 다량의 유효성분도 함께 생산되어지면 이들 성분은 oil상에서 확인된 물질과는 동일한 성분은 전혀 없는 verbenone, ${\alpha}$-terpinieol, fenchol, 등의 성분으로 이루어짐을 확인하였다. 얻어지는 잣나무 피톤치드 oil의 다양한 구성 성분들은 column chromatography법에 의해 그 분리가 가능함을 확인하였다.