• 한국전산유체공학회지
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• 제11권3호
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• pp.1-7
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• 2006

Euler and Navier-Stokes flow analyses for helicopter rotor in hover were performed as low and high fidelity analysis models respectively for the future multidisciplinary design optimization(MDO). These design-oriented analyses possess several attributes such as variable complexity, sensitivity-computation capability and modularity which analysis models involved in MDO are recommended to provide with. To realize PC-based analyses for both fidelity models, reduction of flow domain was made by appling farfield boundary condition based on 3-dimensional point sink with simple momentum theory and also periodic boundary condition in the azimuthal direction. Correlations of thrust, torque and their sensitivities between low and high complexity models were tried to evaluate the applicability of these analysis models in MDO process. It was found that the low-fidelity Euler analysis model predicted inaccurate sensitivity derivatives at relatively high angle of attack.

• 과학기술학연구
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• 제13권2호
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• pp.111-136
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• 2013

과학기술혁신을 통해 사회문제 해결을 지향하는 혁신정책이 부상하고 있다. 이 정책은 기술적 측면과 사회적 측면을 통합적으로 고려할 것을 요구하고 있다. 본 연구는 사회문제 해결형 혁신을 위한 '사회-기술기획'이라는 새로운 활동의 필요를 제시하고 그것의 특성과 발전방향을 제시하였다. 이를 위해 본 연구는 국내외에서 이루어지고 있는 사회-기술기획 활동 사례를 살펴보고 그 성격과 유형을 정리하였다. 그리고 이를 기반으로 사회-기술기획 활동의 발전 방향을 제시했다.

• 대한수학교육학회지:학교수학
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• 제2권2호
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• pp.403-426
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• 2000

In this study, we tried to suggest a meaningful teaching method that is a mathematical thinking-oriented. After referring to the recent trend of mathematics education, we examined the direction that school mathematics should go. Next, we considered previous studies that deals with teaching methods focusing on the mathematical thinking. On the basis of the above examination, we accomplished case studies that aims at mathematical thinking-oriented teaching. And we explained that these case studies reflects the key points didactics of mathematics such as the education of ‘open mathematics’, constructivism etc. Finally, we proposed the necessity of mathematical thinking-oriented teaching in the current state of school mathematics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1281-1282
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• 2007

Effect of tension coating on reducing iron losses of thin grain-oriented 3% Si-Fe steel sheets was investigated. Conventional grain-oriented electrical steel sheets have a forsterite coating layer and a tension coating layer in order to apply tensile stress to the rolling direction of the sheets. However the proposed coating method in this paper is to form only a tension coating layer on the both surfaces of the sheets. Iron losses with the tension coating were reduced by 8% under the condition of 1.7 T and 60 Hz. Consequently the proposed tension coating is applicable to $80{\mu}m$-thick 3% Si-Fe steel sheets.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.77-80
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• 2008

Low-cycle fatigue (LCF) tests were carried out to investigate the effect of loading direction on the cyclic deformation behavior and fatigue resistance of rolled AZ31 magnesium alloy. The as-received alloy showed a strong basal texture indicating that the most of basal planes of hexagonal close-packed structure were located parallel to the rolling direction. Two types of specimens whose loading directions were oriented parallel (RD) and vertical (ND) to the rolling direction. respectively, were used for the comparison. It was found that RD specimens yielded at much lower stresses during compression, while vice versa for the ND specimens, which was mainly attributed to the formation of primary twins. This anisotropic deformation behavior resulted in the different mean stresses during the cycling of RD and ND specimens, affecting the fatigue resistance of two specimens. The ND specimen showed a superior fatigue resistance as compared to the RD specimen under strain-controlled condition.

• 한국세라믹학회지
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• 제49권4호
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• pp.347-351
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• 2012

Vermiculite-silica composites with a layered structure were fabricated by adding cellulose fibers as a pore former and by a simple uniaxial pressing and subsequent sintering process. Three different combinations of additives were used and their effects on the compressive strength and thermal conductivity of the composites were investigated. Both compressive strengths (42-128 MPa) and thermal conductivities (0.75-1.48 $W/m{\cdot}K$) in the direction perpendicular to the pressing direction (T) were higher than those (19-81 MPa and 0.32-1.04 $W/m{\cdot}K$) in the direction parallel to the pressing direction (S) in all samples. The anisotropy in both properties was attributed to the microstructural anisotropy, which was caused by the layered structure developed in the composites.

• 호남수학학술지
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• 제39권4호
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• pp.603-616
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• 2017

In this paper, we give some relations related with a spacelike principal-direction curve and a spacelike binormal-direction curve of a timelike Frenet curve. The Darboux-direction curve and the Darboux-rectifying curve of a timelike Frenet curve in Minkowski 3-space $E^3_1$ are introduced and some characterizations related with these associated curves are given. Later we define the spacelike V-direction curve which is associated with a timelike curve lying on a timelike oriented surface in $E^3_1$ and present some results together with the relationships between the curvatures of this associated curve.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1132-1134
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• 2006

In this research, we examined the correlation between the polymer wall boundary condition and the dynamic/ memory behavior of the ferroelectric liquid crystal (FLC) molecules. It was shown that the polymer wall perpendicular to the rubbing direction induces asymmetric switching to the rubbing direction and induce smaller cone angle angle of LC. On the contrary, in the cell with polymer wall parallel to the rubbing direction, the FLC molecules are oriented in the rubbing direction and shows symmetric switching and has larger cone angle. Memory behavior of each cell has strong correlation with the dynamic state of the FLC molecules. Response time of each cell was also examined.

• 산업융합연구
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• 제17권1호
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• pp.33-39
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• 2019

본 연구에서는 기후변화에 대응하는 도시개발의 실천적 실행을 위해서 기후위험요인 측면과 환경적인 측면으로 대별하여 도시개발 방향과 시사점을 제시하는데 목적을 두었다. 연구방법으로는 정성적인 자료조사와 분석을 통해 이루어졌다. 연구결과, 기후위험요인에 따른 도시개발방향은 도시계획수립시 기후변화 영향을 통합적으로 고려할 수 있는 지역별 부문별 영향 및 취약성 분석을 실시함으로써 자연재난에 대한 피해예방 시스템 구축과 자연재해 위험도 분석을 실시해 도시개발을 할 수 있는 여건 마련의 중요성을 강조하였다. 환경적측면의 도시개발방향은 친환경적인 도시개발을 위해서는 도시계획수립시 대중교통지향적인 도시개발(TOD, Transit­oriented Development)의 추진이 지속가능하고 실행적인 도시개발을 실현하는데 그 필요성을 제시하였다. 향후 연구방향은 보다 더 정량적이고 실증적인 규명을 위한 연구가 보완되어야 할 것이다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.248-248
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• 2003