• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.53.4-54
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• 2015

분자운의 광대역 분포는 작은 영역에서는 볼 수 없는 독특한 모습을 보여준다. 본 연구는 2010년도 TRAO 관측으로 얻는 외은하면의 $4.3^{\circ}{\times}2^{\circ}$의 광대역 데이터를 사용해서 광대역 분자운 분포의 특성을 분석했다. 광대역 분자운들은 형태학적 특징에 의거해서 네 종류로 분류되었다: chain, twisted filament, speckle, cluster suspect 이들의 특징을 간략히 소개하고 광대역 분자운들을 보는 새 관점으로 분자운 충돌 이론을 소개한다. 그와 함께 광대역 연구의 대표적인 예로 두 전파원을 소개한다. 첫째는 CTB109 (3C 434.1) 근처 분자운이며, 길다란 CO filament가 포함된다. 둘째는 "집게벌레(S157 ab 포함)"로서 강한 별 탄생을 보여주는 특이한 영역으로서 강한 CO emission이 두 개 twisted filament 구조를 보여준다. 연구에는 DRAO HI, IRAS 적외선 자료, DRAO Radio continuum data를 사용했고, CO 자료를 통해서 분자운의 질량과 밀도, 온도 등의 기본 물리량을 계산했다.

• The Journal of shipping and logistics
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• v.34 no.4
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• pp.545-563
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• 2018

This study analyzes the major factors affecting the freight rates of Very Large Crude-Oil Carriers (VLCC) using co-integration and vector error correction models (VECM). Particularly, we estimate the long-term equilibrium function that determines the VLCC freight rate by conducting difference conversion. In the VECM regression analysis, the error term converges toward long-term balance irrespective of whether the previous period's freight rate is bigger or smaller than the long-term equilibrium rate. Thus, even if the current rate is different from the long-term rate, it eventually converges to the long-term balance irrespective of a boom or recession. This study follows Ko and Ahn (2018), which analyzed the factors affecting the chemical carrier freight rate and was published in the Journal of Shipping and Logistics (Vol. 34, No. 2). It is expected that an academic comparison of the results of each study will be possible if further research is conducted on other vessel types, such as container ships and dry cargo vessels.

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.251-257
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• 2010

This paper deals with the attenuation and dispersion of ultrasound in bubbly liquids. Bubble clouds in liquid are formed by a variety of mechanisms, leading to different bubble sizes and spectra. Our aim is to investigate how bubble sizes and spectra affect the attenuation and dispersion characteristics of bubbly liquids. Especially, we highlight the attenuation and dispersion behaviors of nano-bubbles, which have not been reported elsewhere. Computations show that the attenuation and dispersion characteristics of bubbly liquids depend heavily on the quality factors of constituent bubbles. The present study is expected to facilitate in-depth understanding of sound propagation in bubbly liquids.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.35-41
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• 2019

Contrail is a kind of cloud that is formed during the flight by vapor condensation of engine exhaust in a cold atmospheric condition. Owing to the negative effects of contrails on the environment and in military applications, several studies for contrail mitigation had been performed in developed countries. The goal of this research is to design a lab-scale contrail generator, and to validate the contrail mitigation technology suggested by previous studies. The contrail generator was made using superheated vapor and a low temperature wind tunnel. Using this generator, the ineffectiveness of ethanol and surfactant suggested in the previous paper on contrail mitigation was found experimentally.

• Venture DIGEST
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• no.2 s.127
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• pp.56-57
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• 2009

어느날 저녁 귀가 후 잠자리에 들 준비를 하고 있는데 예전에 알고 지냈던 S사장님이 전화를 하셨다. 격 없이 지내던 사이지만 시계는 11시를 가리키고 있었고 목소리도 뭔가 대단히 화가 나 있었다. 전화 내용은 이러했다. 국제특송으로 영국서 6만 원짜리 물건을 받았는데 운임이 물건 값의 두 배인 12만 원이 나왔다는 거다. 한 밤중에 전화기를 들만도 하다. 보통 운임이 물건 값을 넘게 되면 물건을 받는 사람은 화부터 난다. 그런데 막상 따지고 싶어도 운임으로 청구된 금액이 무엇인지를 몰라 답답하기 일수다. 이번 호에서는 운임의 구성에 대해 살펴보기로 하자.

• 프린팅코리아
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• v.11 no.7
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• pp.118-121
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• 2012

16세의 어린 나이에 인쇄에 뛰어든 장회운(58) (주)예인미술 대표이사. 장회운 대표이사는 40여년을 인쇄현장을 직접 누비며 남다른 경영철학으로 (주)예인미술을 종합인쇄기업으로 성장시켰다. 최근에는 상업인쇄에서 패키지인쇄로 사업을 전환하기 위해 하이델베르그의 CD102-6XL을 도입하기도 했다. 장회운 대표를 만나 그의 경영 철학에 대해 들어봤다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.99-101
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• 2007

비종관 관측자료인 기상위성 및 레이더 분석자료에서 위성영상에서 볼 수 있는 서해남부 해상의 스콜라인 형태의 강한 대류운을 무안-진도 레이더 반사도에 의한 수평 및 연직 구조로 살펴보았는데 특히 발달한 대류운 영역이 보다 상세한 반사도 차이로 나타나고, 40 dBZ 이상 강한 반사도 셀이 고도 6km, 20km 정도의 수평규모를 갖는 여러 대류운시스템이 합쳐진 다중세포시스템으로 구성되어 있음을 알 수 있었다. 또한 연구용 X-대역 무안 레이더 반사도 분포를 보면 사이트 주면에 강한 dBZ의 대류운이 자리하고 있어 발달한 강수입자에 의한 감쇄효과 때문에 북서방향과 남서방향의 강한 대류운들이 약하게 잘못 관측되고 있음을 볼 수 있었지만 S-대역 진도 레이더는 발달한 강수 입자에 크게 영향을 받지 않고 고유의 강한 반사도를 제대로 관측하고 있음을 알 수 있었다. 이와 같이 태풍에 의한 직${\cdot}$간접적인 호우, 장마전선의 활성화에 따른 집중호우를 동반하는 중규모대류운시스템에 대해 정확히 정량적으로 판단할 수는 없지만, 관측자료 분석을 통해 중규모대류운시스템을 발달${\cdot}$유지시킬 수 있는 기구의 존재 가능성을 체계적으로 이해하는데 많은 도움이 되었다. 본 연구 결과를 바탕으로 레이더 반사도와 3차원 바람장 그리고 마이크로강우레이더와 광학강우강계에 의한 연직 구름계와 순간적으로 발생하는 강수특성 등 섬세하고 다양한 비종관 관측자료를 이용하여 집중호우를 유발하는 중규모대류운시스템의 강수 구조와 특성 분석 및 예측에 활용될 수 있으리라 기대된다.

• (The)Study of the Eastern Classic
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• no.54
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• pp.253-288
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• 2014

A pen name Chuman(秋巒; a mountain of Fall), Jeong Ji-wun(1509-1561) is a famous person wrote "Cheonmyeong-Doseol" which made two men, Yi Hwang and Ki Dae-$s{\breve{u}}ng$ dispute Sachil-Nobyeon(traditional argument about heart/mind). But except this point, few people of nowadays know who Jeong Ji-wun was. Therefore this paper is made for understanding Jeong Ji-wun in the point of view in history of thought. "Cheonmyeong-Doseol" by Jeong Ji-wun had systemized traditional theory of Cheonil-Habil(sky and human are an organic body), through this theory, Jeong Ji-wun had taken an important role who developed the Neo-Confucian theory in the field of political thought at that time. All Neo-Confucian literati used the theory of heart/mind as a sole useful method in political field from after King Myeonjong and Seonjo. "Cheonmyeong-Doseol" by Jeong Ji-wun was a first step to this scene. Especially "Cheonmyeong-Doseol" was got famous by arguments of Yi Hwang and Ki $Dae-s{\breve{u}}ng$, great scholars in the history of Chosun Dynasty. They firstly developed Sachil-Nobyeon, Sandan(pure morality) comes from li, Chiljeong(emotions) comes from Ch'i, is it right or not? This argument with "Cheonmyeong-Doseol" raised up the level of Neo-Confucian theory at that time. Like this, "Cheonmyeong-Doseol" was on the first step for Neo-Confucian literati to study and develop their theory of political thought which covered politics in Chosun Dynasty.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.11-19
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• 2021

Contrails are line-shaped clouds formed by the condensation of water vapor from the interaction of exhaust gas from aircraft engines and the high-altitude atmosphere. Contrails are known to aggravate global warming by creating a greenhouse effect by absorbing or reflecting radiation emitted from the Earth. In this study, development of a model that can quantitatively predict the contrail occurrence was conducted for the reduction of contrail, which is likely to form an aircraft certification category in the future. Based on prior research results, a model that can predict the occurrence of contrail between Tokyo and Qingdao was developed, in addition to proposing improved flight altitude that can minimize the occurrence of contrail.

• Explosives and Blasting
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• v.36 no.4
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• pp.26-34
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• 2018

Explosions of vapor cloud formed due to the leakage from installations with flammable fuels have often occurred in Korea and foreign countries. In this study, TNT equivalency method and Multi-Energy method for vapor cloud explosion blast modelling are described and demonstrated in a case study. As TNT equivalency method is simple and direct, it has been widely used for modelling a vapor cloud explosion blast. But TNT equivalency method found to be difficult to select a proper correlation between the amount of combustion energy produced from the vapor cloud explosion and the equivalent amount of TNT to model its blast effects. Multi-Energy method assumes that the strength of vapor cloud explosion blast depends on the layout of the space where the vapor cloud is spreading. Strictly speaking, the explosive potential of a vapor cloud is dependent upon the density of the obstructed regions. In this study, Flixborough accident are analyzed as a case study to assess the applicability of TNT equivalency method and Multi-Energy method. TNT equivalency method and Multi-Energy method found to be applicable if coefficient of TNT equivalency and coefficient of strength of explosion blast are selected properly.