• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.8
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• pp.523-529
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• 2010

We investigate two-dimensional laminar flow around rectangular cylinders placed in a uniform stream. Numerical simulations are performed, using finite volume method, in the ranges of $50{\leq}Re{\leq}150$ and $0.1{\leq}W/H{\leq}1.0$, where Re and W/H are the Reynolds number and the width-to-height ratio, respectively. The immersed boundary method is used to handle the rectangular cylinder in a rectangular grid system. Comparisons with the previous results show good agreement in Strouhal number, drag and lift coefficient. The present study reports the detailed information of flow structure at different width-to-height ratios in the ranges of $50{\leq}Re{\leq}150$.

• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.125-131
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• 1992

기판회전 테이블이 부착된 DC, RF-magnetron sputtering 장치로 유리기판 위에 제작한 1000 .angs. 정도의 8.8 .angs. Tb/X .angs. Fe (X=5.4~11.0) 다층박막에 관하여 시료진동형 자 기계와 타원편광 분석장치를 사용하여 자화, 수직자기이방성, kerr 회전각의 Fe층 두께와 열처리 온도 의존성이 연구되었다. Fe층 두께가 7.8 .angs. 기점으로하여 자화용이축의 전이가 나타나기 시작하여 6.4 .angs. 일때 수직자기이방성을 나타낸다. 실험치로부터 계산한 Fe와 Tb층의 경계면 수직이방성 에너지 $K_{s}$ = -0.38 erg/$cm^{2}$이고, Fe층만의 체적수직이방성 에너지 $K_{v}$ = -8.50 * $10^{5}$ erg/$cm^{3}$이다. Polar Kerr 회전각은 Fe층 두께 7.8 .angs. 에서 그대값 2 .THETA. $_{k}$ = 1.22 .deg. 를 갖는다.다.다.다.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.356-363
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• 2003

The CWR of the plate girder bridges in non-ballast causes the additional axial force on the rail and the bearing due to the temperature axial force and the interaction between the CWR and bridges. This study shows the remarkable improvement of reducing the axial force of the CWR on the non-ballast bridge, compared to conventional methods. New method, which is differently designed in terms of longitudinal semi-rigid bearing, reduces the axial force on the bearing by making the girder act both directions. This method is applicable to most cases of bridges regardless of the restriction of length, and useful to reduce the abrasion and damage of the track material.

• Journal of Industrial Technology
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• v.31 no.A
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• pp.21-25
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• 2011

A comparison of temperature distributions along the fin length coordinate between two different fin tip boundary conditions for a circular pin fin is made by using the one-dimensional analytic method. One tip boundary condition is the actual fin tip boundary condition and fin tip temperature is arbitrarily given for another fin tip boundary condition. The value of the fin base temperature is depend on the fin base thickness and fin radius. One of the results shows that the temperature distribution along the fin length coordinate for the actual fin tip boundary condition and that for the arbitrarily given fin tip temperature are the same if the arbitrarily given fin tip temperature and the fin tip temperature for the actual fin tip boundary condition are the same.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.34-34
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• 1998

일반 항공기 및 상용 복합 구조재의 경우에는 내부에 결함이 생길 경우 유지 및 보수가 용이하나 복합재 압력 용기의 경우에는 다양한 환경 변화를 겪게 되며 또한 유지 및 보수가 힘들다는 제약 조건이 있으므로 단열재로 사용되는 인슈레이션 고무와 FRP간의 접착, 가황 고무와 미가황 고무 사이의 접착 등 여러 가지 이종 재질들 간의 접착이 매우 중요한 변수가 될 뿐만 아니라 압력 용기의 전체적인 성능에도 상당한 영향을 미치게 된다. 이러한 시스템들은 제작 조건에 따라 결함이 발생하는 빈도가 차이가 나며 특히 가혹한 환경 조건하에서도 내구성을 보여야 하므로 본 실험에서는 다양한 환경 조건, 성형 조건을 가지는 FRP/고무, 고무/고무 접착 시스템의 계면 접착력을 측정한 후 이로부터 환경 노화에 저항성이 강한 최적의 접착제 및 접착 조건 등을 확립하고자 하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.65-67
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• 2017

Various combustion modeling approaches have been developed and verified in a combustion system such as rockets, gas turbines, and so on. This study introduces basic theory and recent research activities on 1D network model where a system is divided into a series of acoustic element and mass/momemtum/energy conservations are applied in the component. Each component is connected to the neighboring ones with proper jump conditions. Flame transfer function and acoustic transfer function are determined and effects of the each function on the system instability is investigated.

• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.479-484
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• 2001

The analysis of photonic band gaps and anomalous dispersion phenomena in photonic crystals requires understanding of band structures and dispersion surfaces. We show the results of the calculation of band structures and dispersion surfaces for a few two- dimensional lattices, using the finite-difference time-domain method with periodic boundary conditions. In addition, localized defect modes the exist within the band gap are computed by the same method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.302-312
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• 1992

Three dimensional velocity measurements of a 35.deg. inclined jet issuing into turbulent boundary layer on both concave and convex surfaces have been conducted. To investigate solely the effect of each curvature on the flow field, streamwise pressure variations are minimized by adjusting the shape of the opposite wall in the curved region. From the measured velocity components, streamwise mean vorticities are calculated to determine jet-crossflow interface. The results on convex surface show that the injected jet is separated from the wall and the bound vortex maintains its structure far downstream. On concave surface, the secondary flow in the jet cross-sections are enhanced and in some downstream region from the jet exit, the flow on the concave surface has been developed to Taylor-Gortler vortices

• 한국IT서비스학회:학술대회논문집
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• 2008.05a
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• pp.339-342
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• 2008

최근 IT서비스 산업은 복잡한 서비스 시스템 통합과 더불어, 제품과 서비스의 융/복합화를 위한 IT서비스 제조 (manufacturing)산업으로 활발히 확장되고 있다. 이는 제품의 서비스화 (product servicize)와 서비스의 제품화 (service productize) 현상의 가속화로 인해 제품과 서비스의 구분이 모호해 지고 있는 산업변화에 대응하려는 산업의 노력으로 판단된다. 고객 가치 향상을 위해 IT서비스 제조산업에서는 제품과 서비스의 모호한 경계를 극복하고, 서비스중심의 신규 IT서비스를 개발할 수 있는 무형의 프로세스 정립이 요구되었다. 본 연구에서는 서비스 사이언스 측면에서 제공되는 이론들 (NPD, NSD, UCD, Contingency theory)을 검토하여, IT서비스 제조산업의 특성이 반영된 마케팅 지원 process template를 개발하는 데에 목적이 있다. 제안된 template는 목표시장 및 기술환경의 분석과 동시에 IT서비스 제품 분석을 통해 IT서비스 사업 마케팅 기회를 전략적으로 탐색할 수 있는 도구가 될 수 있을 것으로 판단된다.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.1
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• pp.79-86
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• 2009

The purpose of this study is to suggest the design guidance of education facilities by analysing Alvaro Siza's education facilities of which considered having idiosyncratic spatial characteristics. Focusing on the his planning of learning and transitional space of education facilities, this study aims at eliciting the spatial characteristics of his architecture. In doing so, this study tries to figure out his basic method of reification of his basic architectural concept which is articulated in learning space and transitional space of education facilities by introducing the boundary element and penetration of light in order to support student's learning activity and foster abundant cognitive experiences. Therefore, this study presents the feasible supplementary design method for future education facilities to be appropriate not just for quantitative factors, but for qualititative aspects such as user's psychological fulfillment, and emotional satisfaction.