• 제목/요약/키워드: Keyhole

검색결과 140건 처리시간 0.029초

Supraorbital Keyhole Approach for Intracranial Aneurysms : Transitioning from Concerns to Confidence

  • Park, Jaechan
    • Journal of Korean Neurosurgical Society
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    • 제63권1호
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    • pp.4-13
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    • 2020
  • For surgical minimalism to reduce iatrogenic traumatization, a supraorbital keyhole approach has already been successfully applied to treat many unruptured anterior circulation aneurysms. However, using this minimal approach also raises several technical concerns due to the small cranial opening and cosmetic impact of a facial incision. Yet, such technical limitations can be overcome by using favorable surgical indications, slender surgical instruments, and optimized surgical techniques, while excellent cosmetic outcomes can be achieved using a short skin incision located <1 cm from the supraorbital margin, reconstruction of any bone defects around the bone flap, and meticulous wound closure. Thus, given such reassuring surgical results, in terms of the clipping status, neurological effects, and cosmetic outcomes, any concerns can be transitioned into confidence.

자유표면변형을 고려한 저에너지밀도 및 고에너지밀도 레이저 용접공정 통합 해석 (A Unified Analysis of Low-Power and High-Power Density Laser Welding Processes with Evolution of Free Surface)

  • 하응지;김우승
    • 대한기계학회논문집B
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    • 제29권10호
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    • pp.1111-1118
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    • 2005
  • In this study, a unified numerical investigation has been performed on the evolution of weld pool and key-hole geometry during low-power and high-power density laser welding. Unsteady phase-change heat transfer and fluid flow with the surface tension are examined. The one-dimensional vaporization model is introduced to model the overheated surface temperature and recoil pressure during high-power density laser welding. It is shown that Marangoni convection in the weld pool is dominant at low-power density laser welding, and the keyhole with thin liquid layer and the hump are visible at high-power density laser welding. It is also shown that the transition from conduction welding to penetration welding fur iron plate exists when the laser power density is about $10^6W/Cm^2$.

레이저 키홀 용접의 열원 모델링: Part 2-간극과 두께 차이의 영향 (Heat Source Modeling of Laser ]Keyhole Welding: Part 2-Effects of Cap and Thickness Difference)

  • 이재영;이원범;유중돈
    • Journal of Welding and Joining
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    • 제23권1호
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    • pp.55-60
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    • 2005
  • A three-dimensional Gaussian heat source model is modified to include the effects of the gap and thickness-difference for the laser keyhole welding. The gap of the butt joint influences the welding efficiency such that the melting area decreases linearly with the gap. When the different plate thickness is used such as the tailored blank welding, melting areas of the thick and thin plates are predicted by introducing the thickness-difference factor. The calculated results using the modified heat source show reasonably good agreements with the experimental results.

겹치기 이음부의 레이저용접 동축 모니터링 (Coaxial Monitoring during Laser Lap Welding)

  • 김정학;김철희;김정한;이세헌
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.1294-1298
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    • 2007
  • Welding process monitoring is advantageous for maintaining weld quality and numerous sensing techniques have been developed for laser welding. Coaxial image monitoring enables direct monitoring of the weld pool shape and keyhole behavior, but requires the complex optical system and the image processing technique. In this study, we coaxially acquired the weld pool images during laser lap welding by using the camera and special illumination. The welding characteristics - pool width and length, keyhole shape, etc - were extracted by using image processing and the relationship between these characteristics and the penetration depth were investigated.

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가변극성 플라즈마 아크용접을 이용한 알루미늄 합금의 키홀 용접 (Keyhole Welding of Aluminum Alloy by Variable Polarity Plasma Arc Welding)

  • 유준태;탁정수;윤종훈;장영순;이영무;강석봉
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2006년 추계학술발표대회 개요집
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    • pp.72-74
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    • 2006
  • The application of the variable polarity plasma arc welding process to A12219 is described. The thickness of aluminum alloy is 11.45mm and 5.08mm. 1-pass keyhole welding is applied to butt welding and 2-pass welding is also applied to thick material. During welding, all welding parameters are controlled by automated system and acquired by 10kHz rate. This paper covers the welding parameters, result of non-destructive test and tensile test.

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레이저용접에 의한 알루미늄 박판구조물의 용접변형 해석 (Analysis of Welding Distortion for Laser Welded Sheet Metal Structures of Aluminum Alloy)

  • 권기보;김재웅;김철희
    • Journal of Welding and Joining
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    • 제27권3호
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    • pp.44-51
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    • 2009
  • In this study, welding distortion analysis is performed for various design of tube shape structures which are assembled with aluminum sheet metal. Aluminum 5052 plates of 1mm thickness are used to analyze. An efficient keyhole model, as a welding heat source, is used for the prediction of full penetration weld size and shape which is required for the thermal analysis. The thermal and mechanical material properties are considered as temperature dependent functions, due to the high temperature variations during the welding. The numerical model is calculated by using a commercial software and evaluated with the experiments. The calculation results could make a comparative study in the view of distortion for the various size and shape of structure.