• Sim-seong Yeon-gu
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• v.38 no.1
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• pp.201-207
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• 2023

• The Science & Technology
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• no.2 s.405
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• pp.16-17
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• 2003

효선제가 국가 공신의 상을 그려서 걸었다는 중국은 기린각. 로큰롤의 성립 발전에 기여한 인물을 기리기 위한 미국의 로큰롤 명예의 전당. 이제 과학인들도 명예의 전당에 오를 수있게 되었다. 과학기술의 발전 및 과학기술인의 자긍심을 높이자는 취지로 시작된 명예의 전당은 고려 말에서 현재에 이르기까지 뛰어난 과학자를 선정하여 논문 등 연구성과를 보존, 전시하는 사업이다. 우선 과학기술부와 한국과학문화재단은 이달 중으로 서울과학관 내에 200평의 공간을 마련하기로 하고, 2006년 경기도 과천에 국립과학관이 완공되며 1층 전시공간을 1000평으로 확대할 계획이다. 이번에 선정된 14인은 인물선정위원회가 과학기술 단체 기관 등이 추천한 과학기술인을 대상으로 국가발전 기여도와 세계적 영향력 등을 평가하여 결정한 인물들이다. 또한 매년 4명 정도를 추가로 선정해 2006년까지 30명 선으로 늘릴 예정이다. 과학기술인 명예의 전당은 과학기술 존중의 분위기를 조성할 것으로 기대된다. 1차로 선정된 14인 가운데 현존하고 있는 안동혁, 최형섭, 이호왕 박사를 만나보았다.

• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.376-408
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• 1991

Recently stereographic projection method has widely been adopted in Korea as a simple but effective way of anlalysing the rock slope stability at the preliminary stage of site investigation. In practice, however, not a few cases have been noted where the method. even with the aid of computer programme, was unproperly applied due to lack of experience in the process of collecting geological data, sorting them out and assessing the potential instability of rock block thereform. This paper will briefly describe basic principles of stereographic projection method and present several instances to discuss its merits and limitations when it is applied to the geological conditions of Korea.

• Transactions of Materials Processing
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• v.4 no.1
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• pp.59-69
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• 1995

A simple kinematically admissible velocity field is proposed to determine the final-stage extrusion load and the average extruded length in the square-die forward extrusion of regular polygonal-shaped bars from circular billets. From the proposed velocity field, the upper-bound extrusion load and the average extruded length are determined by minimizing the total power consumption with respect to four parameters. Experiments have been carried out with hard solder billets at room temperature. The theoretical predictions of the extrusion load are in good agreements with the experimental results and there is generally reason able agreement in average extruded length between theory and experiment.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.136-141
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• 2004

The gear in various mechanical components easily occurs at damages by the external torque. The main failure modes of the gear are surface pitting with the tooth surface and breakage with tooth root by caused fatigue. Therefore, the gear is very important role in the reliability research since it may cause fatal damage of entire system such as the gear box in automobile transmission. In this study, the failure mode of the gear was analyzed and accelerated durability analysis was employed for the life estimation of spur gears. In the case of assumed load spectrums, the reliability of spur gears was evaluated by inverse power law-Weibull accelerated life test model with cumulative damage exposure.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.12
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• pp.136-141
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• 1996

In this paper, the design variables of the extruded parts involving flat die through model experiment are investigated to overcome some current problems such as bending and twisting and get more improved quality products. Above all, the deformation behavior is analyzed in experiment and investigated flow charactristics inside container. Finally, the straight extruded product is obtained by modified bearing land width on the basis of the exit velocities distribution from bended and twisted products.

• Transactions of Materials Processing
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• v.7 no.2
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• pp.177-185
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• 1998

The kinematically admissible veolcity field is developed for the shapes of dead metal zone and the curving velocity distribution in the eccentric plane dies extrusion. The shape of dead metal zone is defined as the boundary surface with the maximum friction constant between the deformable zone and the rigid zone. The curving phenomenon in the eccentric lane dies is caused by the eccentricity of plane dies. The axial velocity distribution in the plane dies is divided in to the uniform velocity and the deviated velocity. The deviated velocity is linearly changed with the distance from the center of cross-section of the workpiece. The results show that the curvature of products and the shapes of the dead metal one are determined by the minimization of the plastic work and that the curvature of the extruded products increase with the eccentricity.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.61-66
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• 1995

이 논문의 목적은 육방형 핵연료집합체로 구성된 3차원 노심을 해석하기 위한 다항식전개법을 개발하는 것이다. 이를 위해 3차원 육방형 핵연료 집합체를 6개의 3차원 프리즘노드로 분할하였다. 그리고 각 꼭지점에서의 점중성자속, 프리즘 각면의 면중성자속과 노드평균중성자속을 미지변수로 하여 다항식전개법에 의해 프리즘노드내의 중성자속분포를 근사하였다. 각 중성자속간의 관계식으로서 프리즘노드내에서의 노달중성자평형식, 두 노드사이의 면에서의 중성자류 연속관계식, 각 꼭지점에서의 중성자누설평형식을 사용하였다. 다항식전개법은 해석함수 전개법에 비해 약 3배정도 빠르며 4군확산방정식에도 훌륭이 적용되었다. 그리고 VVBR-1000 3차원 벤치마크 문제에서 최대출력오차 2.6%, VVER-440 3차원 벤치마크 문제에서 12 평면과 24평면으로 나눈 경우 각각 최대출력오차 15%와 6.6%, SNR 3차원 문제에서 8 평면과 16 평면으로 나눈 경우 각각 최대오차 5.4%와 2,6%를 보였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1912-1920
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• 1997

In the analysis of metal forming process, ALE(Arbitrary Lagrangian Eulerian) finite element methods have been increasingly used for the capability to control mesh independently from material flow. The methods can be divided into two groups i.e., coupled and split formulations. In the present work, the split ALE formulation is used for computational efficiency. A split ALE finite element method developed for rigid-viscoplastic materials and applied to the analysis of hot square die extrusion. Since thermal state greatly affects the product quality, an ALE scheme for temperature analysis is also presented. As computational examples, profile shapes as square and cross-like sections are chosen.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.130-136
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• 1997

The velocity distrubution at the exit of extrusion die depends on the width of bearing land very much. When uniform bearing land without flow guide is used, the material which is extended through the same die does not, deflect to the constant direction, but when the flow guide is equipped and then the volume compensation is done accurately, the material deflects to one constant direction. Therfore, the part of problem can be known exactly, and extrusion products of straight shape can be produced by the corrected bearing land width.