• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.13-18
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• 2009

In this study, an equivalent unit load methodology has been presented to simplify the fatigue analysis procedure. And fuselage structure fatigue life has been evaluated based on equivalent unit load. Finite element analysis has been carried out to analyze the stress intensity factor and geometrical correction factor that is needed for crack growth analysis. And strain energy density factor is used to predict the initial direction of crack propagation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.340-346
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• 2013

This paper describes a helicopter vibration induced by main rotor in forward flight. The hub loads in the fixed frame, which are dominant source of helicopter vibration, are obtained by multi-blade summation of rotating blades loadings. The components of 3/rev, 4/rev, and 5/rev blades loadings are transmitted by blades to 4/rev hub loads in the fixed frame. The vertical vibrations of helicopter at pilot seat and copilot seat are calculated through rigid body transfer functions considering airframe to be rigid body. The blades are assumed to be elastic and undergo the flap, lag, and torsion motion and free wake aerodynamic model is used to calculate the precise blade loadings in the analysis. The 4/rev vertical vibration responses are analyzed from rotating blade loadings and fixed hub loadings.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.859-862
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• 2002

The Core Support Barrel (CSB) is a major component of Reactor Internals, and is designed to support and protect the Reactor Core. In this study, Reactor Core, Core Shroud and CSB were simplified to coaxial cylinders and then the offset of Reactor Core & Core Shroud to the dynamic characteristic of CSB was analyzed. For the beam modes, natural frequencies of the cantilevered cylinder are compared with those of the cantilevered beam. And it was found out that shear modulus must be used correctly to convert the shell model to the equivalent beam model. From the dynamic characteristics of the beam model, it was found out that natural frequencies are proportional to the length of Reactor Core & Core Shroud and inversely proportional to the mass. From the comparison with the dynamic characteristics of a beam model and a lumped-mass model it was found out that the size of lumped-mass must be determined considering both the length and the mass of Reactor Core & Core Shroud.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.7
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• pp.1026-1035
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• 2002

The purposes of this study were to classify the front view of trunk of adult males into several kinds of shape and to provide the characteristics and silhouette of each group which has same shape. As the sample, subjects were l290 males of 20 to 54 year-old. The procedure and results were follows; l. The principal component analysis was used to obtain the shape factor of the front of the trunk 8 factors in the front which explained 86.8% of total variance were extracted. 2. As the result of the cluster analysis of factor scores, the font of body was classified in 4 types. 4 types were named X, A, Y and H type in the front considering the characteristics of each type.

• Aerospace Industry
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• s.108
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• pp.36-39
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• 2010

올해로 창사 22주년을 맞은 현항공산업(주), 부산 녹산공단에 위치하고 있는 이 회사는 항공기 날개 제작 및 동체부품 등을 최상의 품질로 생산함으로써 항공기부품 가공 기업의 선도적 역할을 하고 있는 중소기업으로 주목 받고 있다.

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.103.1-103
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• 1994

• 중국학논총
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• no.66
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• pp.189-209
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• 2020

本研究是通过实证分析论证中国朝鲜族企业成长发展是通过与韩国建立社会网络关系获得了企业的竞争力, 同时企业社会资本成就是为企业家所居住城市朝鲜族社会共同体提供了社会基础资本。得出论证结果:第一, 中国朝鲜族企业家具有中国人的国民性同时又具有朝鲜族的民族性。为了进入中国上曾主流社会他们更体现出中国国民性。第二, 他们积极参与居住区域的本民族社会活动以及与本民族成员之间相互交流是为了企业的利益。第三, 他们所获得的成就为企业家所居住城市朝鲜族社会共同体提供了社会基础资本。通过以上研究结果可以为抽象的离散韩国民族概念用超国境的社会网络民族共同体实证分析提供了具体说明。

• The Korean Journal of Malacology
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• v.11 no.1
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• pp.78-91
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• 1995

한국산 산민달팽이(Incilaria frushtorferi)의 웅성생식기관 및 자웅공통생식기관에 대하여 조직화학적 방법을 이용하여 염색하고 광학현미경으로 관찰한 결과 다음과 같은 결론을 얻었다.1. 자웅동체관은 가늘고 꾸불꾸불하고 긴 관으로 대부분 성숙한 정자로 가득차 있었다. 이 관의 내강상피는 단충섬모상피와 단층섬모원주상피 그리고 위중층 원주상패 등 다양한 세포로 구성되어 있었다.2. 대자웅동체관은 위로 소자웅동체관과 알부민성이 있으며, 그 밑으로는 수란관과 연결되어 있었다.이들의 내강상피는 불규칙한 단층섬모원주상피로 구성되어 있으며, 결합조직내 선세포로부터 형성된 산성 및 중성 점액성 과립들이 기막을 통과하여 내강 속으로 분비되었다.3. 전립선의 내강은 키 큰 단층원주섬모세포로 구성되었으며, 결합조직 내의 분비과립세포에서 형성된 중성 점액과립을 상피세포를 통해 내강으로 분비하였다.4. 정관은 직경 0.5 x 0.25mm 정도인 타원형의 관상구조로 이루어져 있고, 이 관을 0.1mm정도의 매우 두터운 근육층이 둘러싸고 있었다.5. 수정관의 내강은 결합조직성 돌기에 의해 4부분으로 분지되어 있으며 내강은 키 큰 단층섬모원주상피세포로 구성되어 있었다. 또한 수정관 주위에는 두터운 환상근층이 둘러싸고 있었는데, 이들 사이에서 2종의 분비성 과립이 확인되었다.6. 상음경은 내강이 십자로 열려있으며, 키 큰 단층섬모원주상피와 단층입방상피세포로 구성되어 있었다. 내강을 구성하는 근육들은 매우 두터웁고 환상근층과 종주근층이 교대로 둘러싸고 있었다.7. 음겨은 상음경이 점점 굵어져서 형성된 큰 형성된 큰 생식기관으로 내강은 주름 형태인 많은 돌기들을 가지고 있었다. 내강상피 세포는 키가 단층원주상피세포와 단층입방상피가 부위에 따라 다르게 분포하고 있으며, 상피세포 및 결합조직에는 두터운 근육층이 있어 음경의강한 운동성이 감지 되었다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.649-654
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• 2010

A three-dimensional numerical study of the WIG-effect vehicle with a direct-underside-pressurization (DUP) system and a propeller is performed to analyze the aerodynamic forces and moments acting on the vehicle. The computational model includes all the compartments of a WIG-effect vehicle, including a propeller in the middle of the fuselage and an air chamber under the fuselage. The DUP system and propeller help considerably reduce the take-off speed and minimize the effect of the hump drag when the vehicle accelerates to take off on water. The airflow is accelerated by a propeller, and the air then enters the air chamber through a channel in the middle of the fuselage, this air helps increase the lift since the dynamic pressure of air is converted to static pressure. However, the air accelerated by the propeller produces excessive drag and creates yawing moment. It is found that the effect of yawing and rolling moments on static stability is negligible.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.99-104
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• 2003

This paper described the general dynamic point for rotor design and the design procedure of low vibration blade. Generally, rotor rotating natural frequencies are determined to minimize hub loads, blade vibration and to suppress ground resonance at rotor design stage. First, through rotor frequency diagram, natural frequencies must be far away from resonance point and rotating loads generated from blade can be transformed to non-rotating load to predict fuselage vibration. Vibration level was predicted at each forward flight condition by calculating cockpit's vertical acceleration transferred from non-rotating hub load assuming a fuselage as a rigid body. This design method is applied to design current Next-generation Rotor System Blade(NRSB) and will be applied to New Rotor which will be developed Further.