• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.4
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• pp.46-51
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• 2007

The irregular fuel surface was observed by the visualization of hybrid rocket combustion. Even though the test condition maintained oxidizer rich environment, the irregular dark fuel surface was formed as the result of incomplete combustion. In order to investigate the correlation of the characteristics of oxidizer flow and the irregular fuel surface, various flow conditions were imposed such as swirl flow, induced swirl flow by helical fuel configuration and straight flow. Test results revealed no correlation was found between oxidizer flow condition and irregular fuel surface. And this can be a commonly observed phenomena in the tests with different fuel/oxidizer combination. Thus, the irregular fuel surface can be a result of the interaction of blowing flow of vaporized fuel and the boundary layer of oxidizer flow. A further study will be required to confirm the assumption for the formation of irregular fuel surface.

• Journal of Music and Human Behavior
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• v.20 no.1
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• pp.1-19
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• 2023

This study explored the role and characteristics of music that contributed to experiences of catharsis in music. An empirical phenomenological study was conducted to explore catharsis with 12 adults. Phenomenological reduction, change of attitude, literature interpretation, and hermeneutic circle were used for data collection and analysis. As a result, three categories, five themes, and 11 sub-themes were identified. The first category, here and now in music consisted of two themes: aesthetic experiences and expansion of musical novelty. The second category, inner connection through music consisted of one theme, re-experience of internal emotions. The third category, immersion and engagement in music consisted of two themes: ventilating or deepening of emotions and internal dynamics. Based on these results, the cathartic characteristics of music are discussed. First, the aesthetics and novelty of music kept participants fully stay in music. Second, music induced a re-experiencing of emotions by triggering memories or stimulating unresolved emotions. Third, the elements of music promoted emotional ventilation, deepening, and internal dynamics. This study is meaningful because it qualitatively examined the roles and characteristics of music that contribute to cathartic experience in the general adult population.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.229-231
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• 2016

제주도에는 170여개의 확인된 동굴이 있으며 그 중에서 천연기념물 동굴이 10개로서 육지의 동굴보다 면적당 천연문화재적 비중이 상대적으로 높은 지역이다. 이러한 특징으로 용암동굴이 세계자연유산으로 등재되는가 하면 세계지질공원으로서 세계적인 랜드 마크로 부각되었다. 그러나 화산분출에 의하여 형성된 용암동굴은 대부분이 지표 가까운 부분에 손등위의 혈맥과 같은 형상으로 한라산을 중심으로 방사형 분포로 형성되어 있어, 장구한 기간 동안 거센 풍화와 지면 응고성 암석의 특성으로 인한 기포와 균열로 수많은 함몰과 붕괴에 직면하고 있다. 이러한 현상을 분석하고 구현하기 위하여 공간정보시스템을 활용하는 방안을 제시한다. 적용결과 땅꺼짐 현상 관련 분석 및 해결방안은 공간정보시스템의 공간정보의 분석기법과 uIT기법에 지질공학적 기법의 융합적 접근이 효과적임을 확인하였다.

• Journal of the Korean Geophysical Society
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• v.7 no.3
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• pp.207-215
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• 2004

As the sea connecting with the East Sea, the Sea of Okhotsk is the most potential area of gas hydrates in the world. In other to examine geophysical structures of gas hydrate-bearing sediments in the Sea of Okhotsk, the CHAOS (hydro-Carbon Hydrate Accumulation in the Okhotsk) international research expedition was carried out in August 2003. In the expedition, high-resolution seismic and geochemical survey was also conducted. Sparker seismic profiles show only diffusive high-amplitude reflections without BSRs at BSR depth. It means that BSR appears to be completely different images on seismic profiles obtained using different frequencies. Many gas chimneys rise up from BSR depth to seafloor. The chimneys can be divided into two groups with different seismic characteristics; wipe-out (WO) and enhanced reflection (ER) chimneys. Different seismic responses in the chimneys would be caused by amount of gas and gas hydrates filling in the chimneys. In hydroacoustic data, a lot of gas flares rise up several hundreds meters from seafloor to the water column. All flares took placed at the depths within gas hydrate stability zone. It is interpreted that gas hydrate-bearing sediments with low porosity and permeability due to gas hydrate filling in the pore space make good pipe around gas chimneys in which gas is migrating up without loss of amount. Therefore, large-scale gas flare at the site on gas chimney releases into the water column.

• Publications of The Korean Astronomical Society
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• v.6 no.1
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• pp.16-26
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• 1991

스펙트럼선의 선폭증대 현상을 방출영역 내 기체입자들이 열운동에 의한 단순 도플러 효과로 가정하여 중심에서 어느 한쪽으로 심하게 치우친 스펙트럼 선윤곽를 해석한다. 본 연구에서는 태양활동영역에서 흔히 관측되는 좌우 비대칭의 선윤곽을 서로 다른 가우스속도분포의 기체성분들이 시선방향으로 중첩된 결과라 해석하고, 최소자승법을 이용한 비선형 선윤곽 맞춤질에 의해 스펙트럼 방출영역에서 떨어져 나가는 기채들의 온도 및 분출속도에 관련된 도플러선폭과 도플러이동량을 구하였다.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.29.3-29.3
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• 2016

19세기 중반에 세이퍼트 은하와 퀘이사의 발견으로 시작된 거대질량 블랙홀 연구는 90년대 중후반에 발견된 역학적 증거를 바탕으로 은하들의 중심에 거대질량 블랙홀이 존재한다는 새로운 패러다임이 나오며 활발한 전기를 맞고 있다. 본 강연은 은하진화 과정에서 블랙홀의 역할을 규명하고 블랙홀의 물리현상을 밝혀내는 연구결과들을 소개한다. 특히 빛의 메아리 효과 등을 이용한 블랙홀 질량측정과 은하와의 공동진화, 가스분출을 통한 AGN feedback 의 주제를 다룰 것이다.

• Journal of Korean Institute of Fire Investigation
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• v.9 no.1
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• pp.35-46
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• 2006

본 연구에서는 변압기의 종류와 각 변압기의 특징에 대해 살펴보았다. 최근 변압기 사고의 발생현황과 통계를 살펴보고, 화재 및 폭발 안정성에 가장 취약한 지상설치형 유입식 변압기를 대상으로 절연유 분출원인 및 폭발 현상 등 변압기 사고의 주요 원인에 대해 이론적으로 연구하였다. 또한, 화재 폭발 메카니즘을 살펴봄으로서 그 위험성을 인지하고, 유입식 변압기의 사고의 방지를 위한 대책 마련을 하고자 하였다.

• Journal of the Korean Institute of Gas
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• v.21 no.3
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• pp.1-8
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• 2017

The purpose of this study is to suggest the rupture disk design(size) and application at the two phase(gas-liquid) flow by runaway reaction at batch reactor. The definition of runaway reaction is abnormally exothermic reaction by the uncontrolled cooling water or deviated operating condition. As a result, the temperature of reactor is rapidly increasing. The causes of runaway reaction are either self-heating reaction or sleeper reaction. General methods of rupture disk size or safety valve are not suitable in the runaway reaction, because of temperature and pressure increasing rapidly in the reactor and the phases of relieving fluid is 2-phase flow. This study case of the reactor incident, the depressurization system such as safety valve and vent installed, however, the system did not relieved the pressure of reactor suitably. The orifice size of the safety valve were designed too small because the size had not been considered the phenomena and character of reaction. The batch reactor design should be considered by referring to the possibility of runaway reaction proposed in this study and the size of rupture disk design method considering 2-phase flow.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.233-237
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• 2007

Recent experimental data shows that an irregular fuel surface pops up during the combustion test. This may contribute to the agitated boundary layer due to blowing effect of fuel vaporization. Blowing effect can be of significance in determining the combustion characteristics of solid fuel within the oxidizer flow. LES was implemented to investigate the flow behavior on the fuel surface and turbulence evolution due to blowing effect. Simple channel geometry was used for the investigation instead of circular grain configuration without chemical reactions. This may elucidate the main mechanism responsible for the formation of irregular isolated spots during the combustion in terms of turbulence generation. The interaction of turbulent flow with blowing mass flus causes to breakup turbulent coherent structures and to form the small scale isolated eddies near the fuel surface. This mechanism attributes to the formation of irregular isolated sopt on the fuel surface.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.675-689
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• 2007

Kilauea volcano's summit area was formed by continuous ind/or sporadic eruption activities for several hundreds years. In this study, we mainly focused on the trace elements characteristics through systematic sample rocks erupted from 1790 to September of 1982. Under the microscope it can be observed some main minerals such as olivine, clinopyroxene. and plagioclase with minor opaque minerals including Cr-spinel and ilmenite. Zr, V, Y, Ti elements show incompatible activities with MgO while Ni, Cr, Co elements show highly compatible properties. Elements like as Ba, Rb, Th, Sr, Nd are highly incompatible to show positive trends with $K_2O$. In the REE diagram LREE is more enriched than HREE suggesting typical Oceanic Island Basalt(OIB) type. It can be suggested that Sr have an effect on the fractionation of plagioclase from the kink in the $K_2O$ variation diagram. Y/Ho ratio diagram shows there was no fluids effect in the historical Kilauea volcano but Zr/Hf ratio diagram shows a significant difference between Kilauea lavas and PuuOo lavas. There are distinctive changes of trace element contents showing in particular abrupt changes of temporal variations between 1924 and 1954. Moreover, PuuOo lavas which had been erupted since 1983 follow these decreasing trends of trace element variation. Therefore, it is strongly suggested that these abrupt changes of trace elements trends result from the huge collapse geological event which formed Halemaumau crater in 1924 causing contamination effects of crustal contents into magma chamber and from the changes of parental magma composition injected into Kilauea volcano's summit magma reservoir.