• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.6-17
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• 2009

The present paper addresses development of a GTT NO96 membrane type 170K m3 LNG carrier targeted to operate in moderate ice infested seas including Baltic Sea, Sakhalin port of Sea of Okhotsk, Murmansk port of Barents Sea, etc. Critical design issues are covered in detail to meet the requirements coming from the missioned operation conditions comprising low design ambient temperature, harsh wave conditions, stringent environmental protection policies, etc.

• Journal of Advanced Marine Engineering and Technology
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• 제37권7호
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• pp.718-728
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• 2013

Analysis of scenarios of transportation oil and gas which produced in the Arctic and others cold seas shows that in the near-term there will be a significant increase of tonnage of tankers for oil and gas and number of ships which should be exploited in difficult ice conditions. For the construction of ice-resistant structures (IRS) intended for production of oil and gas and transportation of these products at ice-class vessels, calculating the load from ice to board the ship and on surface of supports of the platforms are the actuality and urgent tasks. These tasks have one basis in both cases: at beginning of the contact occurs fracture of edge of ice, then occurs compressing of rubble shattered of ice, then they extruding from contact area, after this next layer of ice begin to destruct. At calculating the strength of plating and elements construct of vessels, icebreakers and ice-resistant platforms the specific energy of mechanical destruction ice ${\epsilon}_{cr}$ is an important parameter. For the whole period of study of physical and mechanical characteristics of sea ice have been not many experimental studies various researchers to obtain numerical values of this energetic characteristic of the strength of ice by a method called Ball Drop Test. This study shows that the destruction of the ice from dynamic loading in zone of contact occurs in several cycles, and the ice destructed with a minimum numerical values of ${\epsilon}_{cr}$. The author offer this energy characteristic to take as a base value for the calculation of ice load on ships and offshore structures.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권3호
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• pp.208-215
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• 2011

A full-scale field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. The first Korean icebreaking research vessel 'ARAON', after her delivery in late 2009, had a sea ice field trial in the Arctic Sea during July-August, 2010. This paper describes the test procedures and data analysis on the icebreaking performance of the IBRV ARAON. The data gathered from the icebreaking performance test in the Chukchi Sea and the Beaufort Sea during the Arctic voyage of ARAON includes the speed and engine power of the ship as well as sea ice thickness and strength data. The air temperature, wind speed and heading of the ship were also measured during each sea ice trial. The ARAON was designed to break 1 m thick level ice with a flexural strength of 630kPa at a continuous speed of 3knots. She is registered as a KR POLAR 10 class ship. The principal dimensions of ARAON are 110 m, 19 m and 6.8 m in length, breadth and draft respectively. She is equipped with four 3,500kW diesel-electric main engines and two Azipod type propulsion motors. Four sea ice trials were carried out to understand the relationship between the engine power and the ship speed, given the Arctic ice condition. The analysis shows that the ARAON was able to operate at 1.5knots in a 2.5m thick medium ice floe condition with the engine power of 5MW, and the speed reached 3.1 knots at the same ice floe condition when the power increased to 6.6MW. She showed a good performance of speed in medium ice floe compared to the speed performance in level ice. More detailed analysis is summarized in this paper.

• 한국소음진동공학회논문집
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• 제24권9호
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• pp.667-674
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• 2014

선박의 추진축계는 외부 변동 부하에 의해서 축계 손상을 일으킬 수 있다. 이러한 추진축계의 동역학적인 특성은 운전 중에 일어나는 공진을 견딜 수 있거나 또는 피하도록 설계 및 최적화 해야 한다. 이러한 공진은 대빙급 선박의 추진시스템의 설계에 요구되는 프로펠러에서 유체역학적인 상호작용에 기인한다. 추진축계는 프로펠러와 대빙 사이의 상호관계로 인한 과도부하와 시스템의 공진에 의해서 진지한 응력을 받게 된다. 이 논문은 대빙이 적용된 극지 연구 선박에서 추진축계의 과도비틀림 진동응답을 검토하고자 한다. 추진축계는 전기모터로 구동되는 원동기, 탄성커플링 기어 및 프로펠러로 구성되어 있다. 이론적인 해석은 프로펠러의 대빙 부하를 기진력으로 과도비틀림진동 해석을 수행하였다. 그리고 실선에서 비틀림 진동을 계측하고 공진점을 확인하고 이를 이용하여 추진축계 한계 설계 토크에 대한 적용된 평가 요소를 국제선급연합 규정과 비교하였다. 전기모터를 갖는 추진축계에서 공진을 초래하는 탄성커플링의 강성 선정의 영향을 검토하였다.

• 대한조선학회지
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• 제42권4호
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• pp.45-48
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• 2005

• 대한조선학회지
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• 제42권2호
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• pp.21-25
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• 2005

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.788-799
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• 2014

This study conducted four field measurements of local ice pressure during the icebreaking voyage of the icebreaking research vessel "ARAON" in the Chukchi and Beaufort seas from July to August of 2010. For measurements, 14 strain gauges, including 8 strain gauge rosettes, were set on the bow of the port side. Influence coefficients were determined using a finite element model of the instrumented area and they were used to convert the measured strains on the hull structure to local ice pressures. The converted maximum pressure was calculated as 2.12 MPa on an area of $0.28m^2$. Pressure-area curves were developed from the surveyed pressure data and the results were compared with previously measured data. The study results are expected to provide an understanding of local ice pressures and thus be useful in the structural design of ice class ships.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 춘계학술대회
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• pp.41-42
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• 2015

극해 지역은 채굴가능 매장량의 30% 정도의 각종 천연자원이 매장되어 있으며 기후변화로 인해 북극해 항로를 이용한 운항 및 자원의 수송과 저장을 위해 빙해 선박과 극지용 해양구조물의 수요가 증가하고 있다. 이 연구에서는 아이스 클라스 등 방한기술에 근거하여 빙해 선박에 탑재되는 루버의 기술개발 동향에 대해 고찰 하였다.

• 대한조선학회논문집
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• 제48권6호
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• pp.575-580
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• 2011

Icing problem of ice-strengthened vessels is an important issue when operating in low temperature environment and it can cause damage to deck machineries and emergency equipments. Many ice-strengthened vessels have since been constructed and operated in accordance with the ice class rules such as Det Norske Veritas (DNV), Russian Maritime Register of Shipping (RS), American Bureau of Shipping (ABS) and so on. Therefore winterization is defined as the preparation of a ship for safe operation. In this research, anti-icing performance tests of weather-tight door have been carried out at various temperature conditions($5^{\circ}C$, $-10^{\circ}C$, $-20^{\circ}C$, $-30^{\circ}C$, $-40^{\circ}C$) in the low temperature cold room facility and then, ambient temperature, specimen temperature, electric current and temperature of heating cable were measured during the test operations. This research describes the construction guidelines of weather-tight door based on anti-icing test results to apply to the full-scale vessels.

• 천문학회보
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• 제46권2호
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• pp.66.3-67
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• 2021

Low-mass stars form by the gravitational collapse of dense molecular cores. Observations and theories of low-mass protostars both suggest that accretion bursts happen in timescales of ~100 years with high accretion rates, so called episodic accretion. One mechanism that triggers accretion bursts is infalling fragments from the outer disk. Such fragmentation happens when the disk is massive enough, preferentially activated during the embedded phase of star formation (Class 0 and I). Most observations and models focus on the gas structure of the protostars undergoing episodic accretion. However, the dust and ice composition are poorly understood, but crucial to the chemical evolution through thermal and energetic processing via accretion burst. During the burst phase, the surrounding material is heated up, and the chemical compositions of gas and ice in the disk and envelope are altered by sublimation of icy molecules from grain surfaces. Such alterations leave imprints in the ice composition even when the temperature returns to the pre-burst level. Thus, chemical compositions of gas and ice retain the history of past bursts. Infrared spectral observations of the Spitzer and AKARI revealed a signature caused by substantial heating, toward many embedded protostars at the quiescent phase. We present the AKARI IRC 2.5-5.0 ㎛ spectra for embedded protostars to trace down the characteristics of accretion burst across the evolutionary stages. The ice compositions obtained from the absorption features therein are used as a clock to measure the timescale after the burst event, comparing the analyses of the gas component that traced the burst frequency using the different refreeze-out timescales. We discuss ice abundances, whose chemical change has been carved in the icy mantle, during the different timescales after the burst ends.