• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.379-379
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• 2015

최근 몇 년간 기록적인 집중호우와 태풍으로 인해 홍수피해가 점점 증가하고 있다. 국내 대부분의 하천은 고수부지 또는 제방으로 정비되어있다. 국지적으로 발생되는 집중호우는 수위를 급격하게 증가시켜 하천의 고수부지 또는 제방범람을 야기한다. 집중호우로 인한 흐름이 고수부지 또는 제방을 지나면 흐름양상은 매우 복잡하게 변화한다. 그러나 급격히 증가하는 흐름에 의해 하천의 제방, 옹벽 또는 계단지형으로 형성된 고수부지 등을 지나는 흐름특성을 분석하는 것은 매우 어렵고 이러한 불연속 단면을 고려하여 예측하기는 불가능하다. 이와 같이 급변하는 흐름이 계단형 구조물을 지날 때 잠김/드러남 특성을 조사하기위해 수리 실험을 실시하였다. 수리실험은 길이 6 m, 폭 0.4 m로 제작된 직선수로에서 수행되었다. 급격히 증가하는 댐 붕괴 흐름을 재현하기위해 수로중간에 게이트를 설치하고 상류에 물을 채운 후 빠른 속도로 게이트를 개방하였다. 하류에는 수로를 따라 계단형 구조물을 설치하고 하류경계는 물이 빠져나갈 수 있게 하였다. 하류 초기수위는 첫 번째 계단보다 약간 낮게 설정하였다. 계단형 구조물과 그 주변에 파고계를 설치하여 시간에 따른 수위변화를 측정하였다. 다양한 수리조건을 적용하여 수리실험을 수행하였고 측정된 데이터를 이용하여 급변한 비정상흐름이 계단형 구조물을 지날 때 잠김/드러남 특성을 분석하였다. 차후 이 실험 결과는 하천의 제방 및 계단지형을 고려할 수 있는 고정확도 수치모형을 개발하는 검증자료로 유용하게 사용될 수 있을 것이다.

• Clinics in Shoulder and Elbow
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• v.15 no.2
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• pp.117-122
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• 2012

Purpose: To assess the effectiveness of internal fixation using a precontoured locking compression plate for the treatment of the displaced clavicle fracture by analyzing both radiological and clinical outcomes. Materials and Methods: We reviewed 34 cases of displaced clavicle shaft fracture treated by internal fixation using precontoured locking compression plates between May 2009 and February 2010. Radiological outcomes were analized on the basis of bone union and the differences between the time for bone union depending on sex and age. Clinical outcomes were analyzed on the basis of quick DASH Scores and the differences in the range of motion of the affected shoulder compared to the contralateral shoulder. Results: In the radiological evaluation, all fractures showed bone union, and the average time for bone union was 12.3 weeks, without delayed unions. Time for bone union did not differ significantly with respect to sex and age (p=0.87). In the clinical evaluation, the average final quick DASH Score was 23.5 (range, 12~42). At final follow up, the range of motion after bone union in the affected shoulder was not significantly different from that of the contralateral shoulder (p=0.69). Conclusion: The internal fixation achieved using precontoured locking compression plate in displaced clavicle shaft fracture showed effective bone union and can be considered as a reliable method with fine clinical results showing early range of motion at the shoulder joint.

• Clinics in Shoulder and Elbow
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• v.11 no.1
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• pp.41-45
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• 2008

Purpose: To review the clinical and radiological results after an open reduction and internal fixation with a T-shaped LCP for unstable distal clavicle fractures. Materials and Methods: From February 2005 to June 2006, ten patients with distal clavicle Neer type II fractures were treated with an open reduction and internal fixation with a T-shaped LCP. Bony union was identified by plain radiography. The clinical results were analyzed according to the UCLA scoring system. Results: The mean time to fracture union was 9weeks and union was achieved in all cases. The mean UCLA score was 33.4 (30-35); excellent in 8 cases and good in 2 cases. In one case, loosening of one distal screw was occured and mild AC joint subluxation was observed in another case. Conclusion: 3.5 mm T-shaped LCP fixation is a useful technique for treating unstable distal clavicle fractures. This procedure provide stable fixation with no further AC joint injury.

• The Journal of the Korean bone and joint tumor society
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• v.16 no.2
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• pp.80-86
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• 2010

Purpose: The skeleton is commonly affected by metastatic cancer. The purpose of this study was to evaluate the results of treating metastatic pathologic fractures in lower extremities using locking plates. Materials and Methods: Between 2004 and 2010, we evaluated 12 patients (13 cases) of metastatic pathologic fractures in lower extremities, treated with the locking plate. Mean patient age was 62.2 years (range, 50-81 years), the locations of the fractures were; proximal femur in 2 cases, femoral mid-shaft in 3, distal femur in 3, proximal tibia in 4, and distal tibia in 1 case. The interval to wheelchair ambulation, pain relief and complications were evaluated. Additionally, we assessed operation time and postoperative blood loss. Results: Mean time from operation to wheelchair ambulation was 3.2 days (range, 1-6 days). Mean VAS scores improved from a preoperative score of 8.1 points (range, 7-9 points) to a score of 2.7 points (range, 2-4 points) at 1 week postoperatively. No early complications associated with surgery were encountered. Mean operation time was 88.4 minutes (range, 70-105 minutes), and mean postoperative blood loss was 246.5 ml (range, 130-320 ml). Conclusion: Internal fixation of metastatic pathologic fractures using a locking plate in the lower extremity can be an effective treatment option in the meta- or diaphyseal area of long bones with massive bony destruction or poor bone stock by offering early ambulation, pain relief and low postoperative complications.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.630-635
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• 2001

The stem thrust required to unwedging a gate valve is influenced by the pressure and temperature when the valve is closed and by the changes in these conditions between closure and opening. "Pressure Locking" and "Thennal Binding" refer to situations where pressure and temperature effects cause the unwedging load to be much higher than normal. A model of these phenomena has been developed. The effects of pressure and temperature are analyzed to determine the change in this disk-to-seat "interference". Flexibilities or Stiffness of the disk and body strongly influence the unwedging thrust. Calculation and limited comparison to data have been performed for the RHR motor operated valve designs and scenario. Pressure changes can increase the unwedging thrust when bonnet pressure exceeds the pressure in the adjacent piping and temperature changes can increase the unwedging thrust when a temperature change after closure produces an increase in the disk-to-seat interference.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.685-692
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• 1991

The pool boiling behavior of a heated surface has been investigated experimentally, focusing on the cases when only a part of the contact surface is heated. Characteristic boiling curves are obtained with circular metal surface test pieces heated below while immersed in Refrigerant-113. Locally heated test pieces are fabricated by inserting a heating block at the center inside a larger conducting block. Overall heat transfer rates are measured while the experimental conditions are systematically varied. The local temperature profiles along the radius are measured for conducting blocks. It is found that the conjugated boiling condition exists and the total heat fluxes should be correlated to a suitably defined temperature difference.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.235-236
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• 2009

파장이 길고 에너지가 낮은 근적외선 영역 광자 두 개를 동시에 여기했다가 형광으로 방출하는 비선형 현상을 이용한 이광자 현미경은 살아있는 세포를 넘어 생체조직 깊은 곳에서 일어나는 생물학적 변화 관찰 및 3차원 이미지 해석이 가능한 매우 효과적인 장비이다. 그러나 상용화된 이광자 현미경은 매우 고가이고 응용의 다양성을 위한 구조적 변형이 매우 힘들다. 본 논문에서는 모드잠김 이터븀 광섬유 레이저를 이용하여 비용 효율이 높고 다루기 쉬운 이광자 현미경을 구현 하고자 한다.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.381-389
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• 1998

The time variation of an ion current density has been analyzed based on the plasma particle dynamic model for the plasma immersion ion implantation. The implanted ion current density has its maximum value at a particular time after sheath formation, and decays. The influence of the particle collisions, the capacitive time of the substrate, and the pulse formula has been represented on the implanted ion current.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.728-732
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• 2004

In the FE analysis of sheet metal forming, efficient results can be obtained by using shell elements rather than using solid elements. However, shell elements have some limitations to describe three-dimensional material laws. In the recent years, solid-shell element, which has only translational degree of freedom like solid element, has been presented. The assumed nature strain (ANS) and enhanced assumed strain (EAS) methods can be used to remove several solid-shell locking problems. In this paper, ANS method was used for diminish transverse shear locking and EAS method for thickness locking. Using the element, the steel pipe making process from flat plate analyzed effectively, which is including bending and welding.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.183-184
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• 2007