• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.932-935
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• 2005

Three dimensional laser welding technology for light car body is studied. A robot, a seam tracking system and 4kW CW Nd:YAG laser are used for three dimensional robot laser welding system. The Laser system is used 4kW Nd:YAG laser(HL4006D) of Trumpf and the Robot system is used IRB6400R of ABB. The Seam tracking system is SMRT-20LS of ServoRobot. The welding joint of steel plate are butt and lap joint. The 3-D welding for Non-linear Tailored blank is performed after the observation experiments of bead on plate. Finally, the welding process for non-linear tailored blank and front side member is developed.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.35-42
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• 2018

This article presents clean core criticality calculations and control rod worth calculations for TRIGA (Training, Research, Isotope production-General Atomics) Mark II research reactor benchmark cores using Winfrith Improved Multi-group Scheme-D/4 (WIMS-D/4) and Program for Reactor In-core Analysis using Diffusion Equation (PRIDE) codes. Cores 133 and 134 were analyzed in 2-D (r, ${\theta}$) and 3-D (r, ${\theta}$, z), using WIMS-D/4 and PRIDE codes. Moreover, the influence of cross-section data was also studied using various libraries based on Evaluated Nuclear Data File (ENDF/B-VI.8 and VII.0), Joint Evaluated Fission and Fusion File (JEFF-3.1), Japanese Evaluated Nuclear Data Library (JENDL-3.2), and Joint Evaluated File (JEF-2.2) nuclear data. The simulation results showed that the multiplication factor calculated for all these data libraries is within 1% of the experimental results. The reactivity worth of the control rods of core 134 was also calculated with different homogenization approaches. A comparison was made with experimental and reported Monte Carlo results, and it was found that, using proper homogenization of absorber regions and surrounding fuel regions, the results obtained with PRIDE code are significantly improved.

• 기술혁신학회지
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• 제19권2호
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• pp.302-323
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• 2016

내부 연구개발 같은 공식적인 연구개발 활동은 기술혁신을 견인하는 중요한 요소로 인식되어 왔으나, 직무훈련, 진보된 생산기술의 도입, 디자인 활동 같은 다양한 부대적인 혁신 관련 활동들도 기술혁신 성과를 제고하는데 긍정적인 영향을 미칠 수 있다. 본고는 이러한 비공식적인 연구개발 활동 여부가 기업의 기술혁신 도입에 차이를 가져오는지, 공식적인 연구개발 활동 중심 집단과 비공식적인 연구개발 활동 중심 집단 사이에 기술혁신 도입 차이가 있는지를 2012년 한국 기술혁신 활동 조사 데이터를 사용하여 분석하였다. 실증분석 결과, 비공식적인 연구개발 활동이 공정혁신 도입에 유의한 차이를 유발할 수 있으며, 내부 연구개발 활동에만 집중하는 기업보다, 디자인 마케팅 같은 비공식적인 연구개발 활동을 함께 추진하는 기업들이 제품혁신을 더 활발히 도입하는 것으로 나타났다. 본 연구는 (1) 혁신주체들이 공식적인 연구개발 활동과 함께 비공식적인 연구개발 관련 활동에도 관심을 기울여야 하며, (2) 정부의 혁신지원정책도 이러한 점을 감안하여 수립되어야 함을 정책적 시사점으로 제시하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.446-452
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• 2002

This paper Presents a 3-D design and a Vibration control of a new walking R.G.O.(Robotic Gait Orthosis) and would like to develop a simulation by this walking system. The vibration control and evaluation of the new knee joint mechanism on the biped walking R.G.O.(Robotic Gait Orthosis) was a very unique system and was to obtain by the 3-axis accelerometer with a low frequency vibration for the paraplegia It will be expect that the spinal cord injury patients are able to recover effectively by a biped walking R.G.O.. The new knee joint system of both legs were adopted with a good kinematic characteristics. It was designed attached a DC-srevo motor and controller, with a human wear type. It was able to accomodate itself to a environments of S.C.I. Patients. It will be expect that the spinal cord injury patients are able to recover effectively by a new walking R.G.O. system.

• Journal of Advanced Research in Ocean Engineering
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• 제1권4호
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• pp.239-251
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• 2015

In this study, a spectral fatigue analysis was performed for the topside structure of an offshore floating vessel. The topside structure was idealized using beam elements in the SACS program. The fatigue analysis was carried out considering the wave and wind loads separately. For the wave-induced fatigue damage calculation, motion RAOs calculated from a direct wave load analysis and regular waves with different periods and unit wave heights were utilized. Then, the member end force transfer functions were generated covering all the loading conditions. Stress response transfer functions at each joint were produced using the specified SCFs and member end force transfer functions. fatigue damages were calculated using the obtained stress ranges, S-N curve, wave spectrum, heading probability of each loading condition, and their corresponding occurrences in the wave scatter diagrams. For the wind induced fatigue damage calculation, a dynamic wind spectral fatigue analysis was performed. First, a dynamic natural frequency analysis was performed to generate the structural dynamic characteristics, including the eigenvalues (natural frequencies), eigenvectors (mode shapes), and mass matrix. To adequately represent the dynamic characteristic of the structure, the number of modes was appropriately determined in the lateral direction. Second, a wind spectral fatigue analysis was performed using the mode shapes and mass data obtained from the previous results. In this analysis, the Weibull distribution of the wind speed occurrence, occurrence probability in each direction, damping coefficient, S-N curves, and SCF of each joint were defined and used. In particular, the wind fatigue damages were calculated under the assumption that the stress ranges followed a Rayleigh distribution. The total fatigue damages were calculated from the combination with wind and wave fatigue damages according to the DNV rule.

• 동의생리병리학회지
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• 제26권5호
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• pp.665-671
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• 2012

The purpose of this study is to examine the effect of Vigna angularis ethanol extract (VA-E) on papain induced arthritis in C57BL/10 mice. The C57BL/10 mice were injected with papain and oral administration of Vigna angularis ethanol extract (VA-E) at different doses (100 and 200 mg/kg) once a day for 42 days and compared with untreated mice. Histological examination and the measurement of inflammatory cytokine release were performed. The results showed that comparing with untreated mice, the treatment with Vigna angularis ethanol extract (VA-E) decreased the pathological changes of knee joint tissue. The level of inflammatory cytokine secreted from the tissues, such as IL-$1{\beta}$ (interleukin-$1{\beta}$), IL-6 (interleukin-6), TNF-${\alpha}$ (Tumor Necrosis Factor-${\alpha}$), were decreased. These results were confirmed by the quantification of cartilage volume using micro CT scanning. Consequently, Vigna angularis ethanol extract (VA-E) has a therapeutic potential in inflammatory joint diseases such as osteoarthritis.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권3호
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• pp.348-363
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• 2013

The use of I-Core sandwich panel has increased in cruise ship deck structure since it can provide similar bending strength with conventional stiffened plate while keeping lighter weight and lower web height. However, due to its thin plate thickness, i.e. about 4~6 mm at most, it is assembled by high power $CO_2$ laser welding to minimize the welding deformation. This research proposes a volumetric heat source model for T-joint of the I-Core sandwich panel and a method to use shell element model for a thermal elasto-plastic analysis to predict welding deformation. This paper, Part I, focuses on the heat source model. A circular cone type heat source model is newly suggested in heat transfer analysis to realize similar melting zone with that observed in experiment. An additional suggestion is made to consider negative defocus, which is commonly applied in T-joint laser welding since it can provide deeper penetration than zero defocus. The proposed heat source is also verified through 3D thermal elasto-plastic analysis to compare welding deformation with experimental results. A parametric study for different welding speeds, defocus values, and welding powers is performed to investigate the effect on the melting zone and welding deformation. In Part II, focuses on the proposed method to employ shell element model to predict welding deformation in thermal elasto-plastic analysis instead of solid element model.

• 한국가스학회지
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• 제10권2호
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• pp.61-67
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• 2006

폴리에틸렌(PE) 배관 전기융착부에 대하여 위상배열초음파기술을 이용하여 전기융착부에 대한 비파괴검사를 실시하였다. 사례 1은 직경 300 mm의 PE배관 전기융착부에 대하여 3.5 MHz 배열초음파 센서를 이용하여 건전성 평가를 실시하였으며 사례 2는 직경 350 mm 3개의 새들융착부에 대하여 건전성을 평가하였고 사례 3은 400 mm 전기융착부에 대하여 3.5 MHz 배열초음파 센서를 가지고 비파괴검사를 실시하였다. 그리고 검사한 결과를 절단시험 결과와 비교하였다. 사례 4는 도시가스의 공급압력이 300 kPa인 400 mm PE배관 전기융착부를 탐상하고 그 결과를 살펴보았다.

• Journal of Welding and Joining
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• 제31권6호
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• pp.58-64
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• 2013

Several joining methods involving resistance welding, laser welding, ultrasonic welding and mechanical joining are currently applied in manufacturing lithium-ion batteries. Cu and Al alloys are used for tab and bus bar materials, and laser welding characteristics for these alloys were investigated with similar and dissimilar material combinations in this study. The base materials used were Al 1050 and oxygen-free Cu 1020P alloys, and a disk laser was used with a continuous wave mode. In bead-on-plate welding of both alloys, the joint strength was higher than the strength of O tempered base material. In overlap welding, the effect of welding parameters on the tensile shear strength and bead shape was evaluated. Tensile shear strength of overlap welded joint was affected by interfacial bead width and weld defect formation. The tensile-shear specimen was fractured at the heat affected zone by selecting proper laser welding parameters.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2003년도 추계학술발표회 논문집
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• pp.53-58
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• 2003

API 5L X65 배관에 50mm이상의 단관을 삽입하여 용접하였을 경우, 삽입된 단관 길이 변화에 따른 용접부 기계적 특성 평가 결과를 요약하면 다음과 같다. 1. 단관삽입 용접부위의 거시적 조직관찰, 미소경도측정, 인장시험, 굽힘시험을 수행한 결과, 단관삽입 용접부의 건전성에는 문제가 없는 것으로 평가되었다. 2. 단관삽입 용접부의 원주방향 최대 인장 잔류응력의 크기는 단관 삽입 길이에 관계없이 약 150MPa로서 그리고 최대 압축 잔류응축은 약 300MPa로 측정되었다. 모재의 항복강도가 492MPa인 것과 비교하여보면 단관 삽입 용접에 의한 잔류응력의 영향은 매우 작은 것으로 평가되었다.