• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.321-331
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• 1999

A numerical study is carried out for increasing heat removal using indirect cooling system. Computation is performed for nine cases as variation of flow condition in the lower channel. As the result of this study, water is more effective than air at the same pressure loss in spite of the lower inlet velocity. In channel configuration, the vertical channel is more effective than horizontal channel because of the buoyancy effect. Under the condition that heat generation is the same, counter flow effectively decreases the temperature difference among blocks. Parallel flow is more effective than counter flow when average temperature of all blocks is considered. In the case of installing obstacles in the lower channel, it is desirable to install obstacles in the bottom of lower channel. Heat transfer rate increases as the height of obstacles increases.

• Journal of Fisheries and Marine Sciences Education
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• v.22 no.1
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• pp.91-98
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• 2010

물류산업은 세계의 모든 정부 및 국가기관에 의하여 최고로 인식되고 있는 전략적이고 경제적 이윤추구의 전 세계에 걸친 거대한 산업이다. 싱가포르는 물류산업이 가장 발달하고 최고로 바쁜 항만을 갖고 있는 국가 중의 하나이다. 싱가포르의 강점은 아시아에서 훌륭한 문화여건, 금융과 상업적인 클러스터, 통신 및 운송의 연결성을 가지고 있는 가장 세계화된 도시라는 점이다. 싱가포르는 우수한 물리적인 산업기반 시설의 장점에 의하여 자유경쟁의 이득을 향유하고 있다. 그렇지만 이러한 것들만으로는 싱가포르가 우리들의 경쟁자로서 앞서 있다고 확신하기에는 충분하질 않다. 싱가포르는 적은인구와 지지배후지의 부족 등으로 도전에 직면하고 있어서 배후지를 다른 국가로 이전하고 있다. 싱가포르는 세계 경제 속에서의 국제화 중심이 되거나, 남동아시아 성장에 참여하고 배후지의 결속을 증가시키는 선택을 해야 될 것이다. 따라서 이 논문에서는 싱가포르 물류산업의 전략적 발전을 분석하기 위하여 수리통계학적 방법을 적용하였다.

• Korean Journal of Child Studies
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• v.30 no.5
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• pp.103-117
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• 2009

This study examined patterns of delinquent behavior trajectory from late childhood to early adolescence and examined relationships between patterns of trajectory and individual, family, and school factors. Youth delinquent behavior trajectories were examined by mixed growth models using data from the 2nd to 5th year surveys of the Seoul Panel Study of Children. Relationships between patterns and effect factors were examined by multinominal logit models. Four patterns emerged: non-delinquency (80%); rapidly accelerating delinquency (3.3%); decelerating delinquency (6.0%); and moderately accelerating (10.7%) groups. Contacts with a delinquent peer group had persistent effects on more serious delinquent behavior trajectories. Increased levels of self-esteem and school achievement prevented increase in delinquent behaviors; close relationships with parents and parental supervision caused decrease in delinquent behaviors.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.11-16
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• 2005

Sleep can be easily disrupted by variety of conditions. Most of medical illnesses could be a primary condition causing secondary insomnia. The common underlying mechanism of secondary insomnia is presumed to be stress effects on sleep. The assessment and treatment of secondary insomnia are often complicated. Establishing an causal inference between primary condition and insomnia is the key to assessment. However, it can be difficult even for experienced clinicians due to diagnostic ambiguity of secondary insomnia. Therefore, through medical evaluation and integrative understanding of primary condition is essential to manage secondary insomnia properly. Although treatment have been usually focused on the primary medical illnesses per se, nonpharmacologic interventions, such as sleep hygiene, might be effective in many cases.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.162-166
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• 1993

Spodumene$(LiAlLi_2O_6)$ single crystal was grown by Floating Zone process using the image furnace having the halogen lamp as heat sources. The crystal had the dimension of 50~60mm length and 6~8mm diameter. The colors of as-grown crystals were green, black and pale green respectively. The composition of the crystal was analized by XRD and FUR measurement. Growth orientation was examined by Laue back reflection pattern and for measuring the light transmittance, OPtical transmittance was measured.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1623-1629
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• 2008

The purpose of this research is to assess the application of recycled-aggregate that is gained from construction wastes as the material of compaction pile method. At the same time, the development of the new technique rectifies defects of the existing compaction pile method for soft ground improvement. In this research, model tests were conducted for analyzing the effect of the soft ground improvement by porous concrete pile using recycled aggregate. Through the results of the model tests, the behavior of settlement on composition ground with surcharge pressure were elucidated.

• Journal of Hydrogen and New Energy
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• v.29 no.5
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• pp.483-489
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• 2018

Recently proposed organic flash cycle (OFC) was shown to potentially improve power generation using low grade heat source. In this paper, a thermodynamic performance is carried out for a modified OFC employed double expansions. Effects of the selection of working fluid and the important system parameters such as the temperatures in flash evaporators on the system performance were extensively investigated. Results showed that the system performances are strongly influenced with the system parameters and selection of the working fluid, and the power generation can be increased compared to the basic OFC.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.12-18
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• 2001

The objective of the present work is to examine the effect of inclined angle of channel with multi heat source on thermal stability of electronic equipment. The heat sources are mounted on both sides of channel walls by two kinds of configuration such as the zig-zag md symmetric on. Conductive heat transfer was estimated by using of thermocouples and heat flux sensor. Thus, convective heat transfer and mean Nusselt number could be obtained. With increased inclined angle, the convective heat transfer coefficient was decreased. When inclined angle was smaller than 30 degree, The average Nusselt number of Big-zag configuration was larger than that of symmetric. Furthermore, when protruding ration was 0.082, the temperature was strongly affected by inclined angle. whereas, when protruding ration was 0.25, the temperature was strongly affected by heat source configuration.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.55-57
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• 2011

경인 아라뱃길이 2011년 10월 개장을 앞두고 있다. 경인 아라뱃길이 시작되는 경인항 서해갑문 입출거시 예선사용기준에 대한 연구는 선박운항의 경제성 측면에서 매우 중요한 의미를 지닌다고 할 수 있다. 통상 선박의 크기(톤수)에 따른 예선의 소요마력 및 사용 척수는 대상선박의 크기, 모양, 접근수로, 부두시설의 위치 및 종류, 기타 환경조건 등의 영향을 받으며, 선체에 작용하는 수면상부의 풍압력과 수면하부의 유압력을 고려하여 규정하고 있다. 따라서 본 연구에서는 국내외 예선 규정 및 대상선박에 대한 예선 조종시뮬레이션을 통하여 경인항 서해갑문 입출거시 사용되는 예선의 기준을 설정하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.61-62
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• 2011

이 연구는 경인아라뱃길 중의 경인항 인천 컨테이너터미널의 부두축조에 있어서 터미널 활용의 경제성을 감안한 대상 선박의 조종성능 및 운동성능을 검토하고, 대상선박의 통항 및 접 이안 안전성 확보에 필요한 적정 수역 및 부두길이를 확정하여 준설토 투기장의 부족문제 해결을 위한 부두전면의 최선의 준설범위를 결정하는 데 그 목적이 있다. 이를 위하여 550 TEU급 컨테이너선을 인천갑문 쪽으로 접안 배치하고, 1,000 TEU급의 컨테이너선을 갑문에서 멀리 떨어진 수역에서 접이안 조종함으로써 최대한의 안전성을 확보할 수 있도록 한다. 이러한 상황을 감안하여 인천항 도선사협회 전문가들과의 협의를 거쳐서, 안전한 선박조종 수역을 포함한 최적의 부두길이 결정을 위한 부두배치안 2개(제1안, 제2안)를 설정하여 선박조종 시뮬레이션을 통하여 2개의 안에 대한 대상 선박의 접이안 안전성을 평가하였다.