• 항공우주시스템공학회지
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• 제18권3호
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• pp.70-75
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• 2024

본 연구에서는 단열재 두께에 따른 소형발사체 공통격벽 추진제 탱크의 단열 성능을 분석하였다. 단일 파트로 이루어진 공통격벽 추진제 탱크는 탱크 연결부가 불필요하여 추진제 탱크의 경량화 설계가 가능하다. 그러나 산화제와 연료의 온도차로 인한 열전달에 의하여 추진제의 손실과 점화 지연 등의 문제가 발생할 수 있다. 따라서 산화제 탱크와 연료 탱크를 구분하는 공통격벽 구조의 단열 성능 확인이 필수적이다. 본 연구에서는 기화 질량(boil- off mass)을 이용한 단열 성능 분석을 위하여 단열재 두께가 50, 55, 60, 65, 70 mm인 추진제 탱크에 대해 과도 열전달 해석을 수행하였다. 이어서 추진제 탱크의 1단 비행시간 동안 발생하는 산화제의 기화 질량을 도출하였다. 그 결과, 단열재 두께가 증가할수록 기화 질량이 감소하여 단열 성능이 향상되었다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.166-171
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• 2008

LNG carrier is a special-purpose vessel to transport natural gas (NG) from the place of origin to each consuming country. To increase the capacity of canying LNG carrier, the natural gas is conveyed as a state of liquid called LNG (Liquefied Natural Gas) during a voyage because the total volume of NG is surprisingly reduced when it is cooled down to $-162^{\circ}C$. That is why the design of insulation of the carriers is important to protect LNG from the external heat invasion, and it has been a great challenging subject for several decades in the shipbuilding industry. For this ultimate goal, the boil-off rate (BOR) needs to be accurately estimated during a voyage. Therefore, the goal of this study is to propose a numerical method for estimating the BOR of LNG for given insulation containment subject to external temperature conditions during voyage.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1192-1200
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• 2008

This paper is concerned with the thermal design of the $138,000m^3$ class membrane type LNGC. To predict the temperature distribution, BOG and BOR, 3-dimensional numerical calculation was carried-out for the quarter of No.3 LNG tank. These sequence analyses were performed under the standard conditions of IMO ship design condition, USCG ship design condition and the Korean flag LNGC's route condition according to the 6-voyage modes. As the results, temperature behavior, heat flux, total penetrating heat, BOG and BOR were obtained, and those were compared with the maneuvering results considering the real temperature variation of air and sea water temperature at noon time. For securing the safety of LNGC during the ballast voyage, optimum control patterns of pressure and temperature in LNG tank is suggested in this paper.

• 한국식생활문화학회지
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• 제1권4호
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• pp.335-349
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• 1986

'Zu Bang Moon', a book of cooking, was written in Korean in the 17th century by Mr. Hwa. Various cooking methods of traditional foods were described in this book. The kinds of cookingfoods were Wine 28, Guksu (noodle) 3, Side dish 23, Seasoning 10, and Dessert 10. The materials used in the cooking foods were cereals, vegetables, fishes, meats, etc. 9 kind of Seasonings used in cooking foods such as salt, and herbs such as black pepper. The cooking methods were different and complicated. The way of heating were also different such as to stew, to boil, to steam, to pan-boil, to frying, etc. Utensils and table wares used for processing and cooking were poor and specific. The measuring units were not accurate and unscientific. Many of special words and expressions which are not used today in cooking and processing were, reviewed.

• International Journal of Concrete Structures and Materials
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• 제7권2호
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• pp.165-174
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• 2013

Portland cement concrete exposed to high temperatures during mixing, transporting, casting, finishing, and curing can develop undesirable characteristics. Applicable requirements for such the hot weather concrete differ from country to country and government agencies. The current study is an attempt at evaluating the hardened properties of the concrete exposed to hot weather in fresh state. First of all, this study reviews the current state of understanding and practice for hot weather concrete placement in US and then roadway sites with suspected hot weather concrete problems were investigated. Core samples were obtained from the field locations and were analyzed by standard resonance frequency analysis and the boil test. Based on the results, there does not appear to be systematic evidence of frequent cracking problems related to high temperature placement. Thus, the suspicious deteriorations which are referable to hot weather concreting would be due to other factors.

• 대한기계학회논문집
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• 제18권4호
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• pp.986-996
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• 1994

Insulation system of LNG carrier has made important roles such as maintaining a proper Boil off Ratio(BOR) for the cargo and avoiding the excessive low temperature of the adjacent inner hull beyond the permissible limit. At the same time, safety and economy of the LNG transportation by the ship are connected with the performance of the insulation system. Also, thermal insulation system of LNG carrier is one of the most advanced technique with the structure analysis of tank, welding and assembling. In this study a computer program is developed to calculate the hull temperature distribution and BOR, which are important factors in thermal design for the Moss Rosenberg Verft spherical tank type LNG carrier. Detailed results for hhull temperature distribution close to LNG tank, BOR and the thickness effect of insulation material are reported in this paper in the range of standare design sea condition.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1280-1285
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• 2003

In the developement of LNG cargo, the current concern focuses on the slim design of insulation layer to increase the LNG carrying capacity. Not only thermal stability with BOR(Boil-Off Rate) but structual stability against the LNG weight and the sloshing phenomenon must be also considered. In this paper, we applied the stitched sandwitch composite called the 3X-Board which is stitched through the core thickness direction using glass fiber to the LNG cargo. We evaluated the thermal and structural characteristics of 3X-Board by changing the core thickness and the material, in order to explore a validity for the slim design through the finite element analysis.

• 대한조선학회논문집
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• 제34권4호
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• pp.108-118
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• 1997

LNG운반선은 일반 상선과는 달리 경제성 관점에서의 적정 Boil-Off Rate(BOR)과 안전성 관점에서의 Steel Grade 결정을 위한 Cargo tank 온도분포 해석이 필수적이다. Membrane형 LNG선의 경우 이미 여러가지 해석이 수행된 바 있지만 대부분이 상당히 영향을 주는 부재들의 영향을 무시하였다. 본 연구에서는 이전의 연구에 더하여 온도 분포 해석에 가장 중요한 대류 열전달 계수의 산정에 더욱 정확한 상관식을 적용하였고 Longitudinal과 Floor등 주요 부재의 영향을 충분히 고려한 3차원 온도분포 해석과 BOR을 산정하는 program을 개발하였다. 또한 여러 가지 경우에 대해 타당성을 검토한 후 그 결과를 설계에 반영하였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제5권1호
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• pp.44-52
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• 2002

To understand the relationship among different quantitative traits, correlation studies were performed by utilizing eighty-eight inbred strains of silkworm, Bombyx mori L. on twelve economic characters. Analysis resulted in correlation of 5th instar period with total larval period (r ＝ 0.7882), cocoon weight with shell weight (r ＝ 0.8326), shell weight with shell ratio (r ＝ 0.5067), shell ratio with raw silk ％ (r ＝ 0.7570), raw silk ％ with filament length (r ＝ 0.3490), filament size (denier) with reelability (r ＝ 0.3193) and boil-off loss % (r ＝ 0.2792). Negative correlation was observed among filament length with filament size (r ＝ 0.7582) and reelability with boil-off loss % (r ＝ -0.3236). Correlation of different quantitative characters for quality silk production is discussed.

• 한국식품영양학회지
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• 제3권2호
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• pp.185-200
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• 1990

"Bok Sik Bang', a book of cooking, was written in Korea in the 17 th century Various Cooking methods Of traditional foods were described in this book. 1. The kinds of cooking foods were Wine(59), Side dish(39), Seasoning(12), and Dessert(5) 2. The materials used in the cooking foods were cereals, vegetables, fishes, meats and etc. 3. The cooking methods were different and complicated. 4. The way of heating were also different such as to stew, to boil, to pan-boil, to frying, etc. 5. Utensils and table wares used for processing and cooking were poor and specific. 6. The measuring units were not accurate and unscientific. 7. Many of special words and expressions which are not used today in cooking and processing were reviewed.ewed.