• 제목/요약/키워드: curvature pinching

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반복하중을 받는 RC기둥의 비선형 해석을 위한 모멘트-곡률 관계의 개발 (Nonlinear Analysis of RC Columns under Cyclic Loading Based on Moment-Curvature Relationship)

  • 곽효경;김선필
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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    • pp.3-11
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    • 2002
  • A moment-curvature relationship to simulate the behavior of reinforced concrete (RC) columns under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the unposed model takes into account the bond-slip effect by using a monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The pinching enact caused by axial force is considered with an assumption that the absorbing energy corresponding to any deformation level maintains constant regardless of the magnitude of applied axial force. The advantages of the proposed model, comparing tn layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures.. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed mood.

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반복하중을 받는 철근콘크리트 기둥의 비선형 거동 (Nonlinear Behavior of RC Columns Subjected to Cyclic Loadings)

  • 곽효경;김선필
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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    • pp.475-482
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    • 2002
  • A moment-curvature relationship to simulate the behavior of reinforced concrete (RC) columns under cyclic loading is introduced. Unlike previous moment4curvature models and the layered section approach, the proposed model takes into account the bond-slip effect by using a monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The pinching effect caused by axial force is considered with an assumption that the absorbing energy corresponding to any deformation level maintains constant regardless of the magnitude of applied axial lone. The advantages of the proposed model, comparing to layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures. Finally, correlation studies between analytical result and experimental studies are conducted to establish the validity of the proposed model.

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자가 진피지방술을 이용한 집게조갑의 교정 (Correction of Pincer Nail using Autogenous Dermofat Graft)

  • 김현성;김철한;강상규;탁민성
    • Archives of Plastic Surgery
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    • 제37권3호
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    • pp.250-255
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    • 2010
  • Purpose: Pincer nail is a relatively rare deformity characterized by an increase in transverse curvature along the longitudinal axis of the nail. This curvature commonly increases from proximal to distal end of nail, leading to pinching, curling, and distortion of the underlying soft tissue and resulting frequently in severe pain. Numerous surgical procedures have been reported. Preserving the width of the nail in the correction of the pincer nail is very important for functional and aesthetic reasons. We report the results of the correction of the pincer nail using autogenous dermofat graft with a good result. Methods: From May 2006 to September 2008, dermofat graft was performed in 6 patients with pincer nail. Patients were four women and two men, and the average age was 51. The affected digits were the unilateral great toes in four patients and the unilateral thumbs in two patients. Average follow-up period was 13 months. Surgical procedure was removal of nail using an elevator to avoid damage to the nail bed. An incision was created in distal portion of hyponychium. Paronychium was dissected from distal phalanx by periosteal elevator through incision of hyponychium and tunnel was made. Then dermofat grafts harvested from inguinal area were inserted into the tunnel. Finally, a silicone sheet was inserted eponychial fold for prevention of synechia. Objective assessment was evaluated by use of the width index and height index. Results: All patients reported resolution of the pain and soft tissue pinching sensation that they had before the operation. There was good adherence between the nail plate and the underlying nail bed. The nails have regrown and were corrected in a normal and flattened appearance. The width index and height index were improved. Conclusion: The autogenous dermofat graft seems to provide an effective treatment of the pincer nail with preservation of the nail matrix.

A GENERALIZATION OF AN INEQUALITY OF LI AND ZHONG, AND ITS GEOMETRIC APPLICATION

  • Chi, Dong-Pyo;Kim, Sang-Moon;Kim, Sung-Ki;Lee, Il-Hae;Lee, Sa-Ge
    • 대한수학회보
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    • 제20권1호
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    • pp.51-54
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    • 1983
  • Let M be a n-dimensional compact Riemannian manifold with sectional curvature bounded below by one. Then Li and Zhong[3], and Li and Treibergs [4] proved that if the first eigenvalue of the Laplacian .lambda.$_{1}$ is less than some universal constant and if n.leq.4, then M is diffeomorphic to the n-sphere S$^{n}$ . The purpose of this paper is to prove this pinching theorem for all n with some extra condition.

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