• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.413-420
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• 2012

An aluminum foil-laminated sheet is a laminated steel sheet on which aluminum foil is adhesively bonded. It is usually used on the outer panel of home appliances to provide an aluminum feeling and appearance on the surface of the product. The delamination of aluminum foil is one of the main problems during the stretch forming process. The purpose of this study is was to determine the delamination limit of an aluminum foil-laminated sheet in the stretch forming process. The delamination was dependent on the bonding strength between aluminum foil and steel sheet. The fracture behavior of the interface between the aluminum foil and the steel sheet was described by a cohesive zone model. A finite element was conducted with the cohesive zone model to analyze the relationship between the delamination limit and the bonding strength of the interface. The interface bonding strength was evaluated by lap shear and T-peel test. The delamination limit of the aluminum foil-laminated sheet was determined by using the bonding strength of the steel sheet. The delamination limit was also verified by the Erichsen test.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.4
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• pp.477-483
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• 2007

In this study, the numerical fire analysis for temperature distribution and spalling behavior of underground concrete box structures that contained lifelines, such as power cables and communication cables. The temperature field of inner space was assumed based on the fire curve with the thermal gradient obtained from CFD analysis. It was assumed that the spalling behaviors of concrete are occurred when the concrete temperature reached the threshold, as dehydration degree. In this case, the elements correspond to spalling parts were removed and the analysis model were updated. Three fire scenarios were analyzed and the results were showed adequate spalling behavior. The bearing capacities of the box structures would be estimated in the companion paper.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.571-575
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• 2016

두꺼운 에어포일은 받음각이 클 때 역압력 구배가 일어날 수 있기 때문에 날개의 중앙부 후방에서 유동박리(Flow separation)와 와류 진동(Vortex shedding)이 쉽게 발생할 수 있다고 알려져 있다. 항공기가 이 착륙할 때 받음각이 커짐에 따라 유동박리에 의한 실속이 발생할 수 있는데 이를 지연 시켜 실속각을 크게 하면 안전성이나 효율 면에서 유리하다. 이를 위해 날개에 Hole을 만들어 와류를 잡아 유동의 박리를 지연시키고자 하였다. 본 연구에서는 EDISON_CFD 시스템의 2D_Incomp_P 솔버를 사용하여 NACA0018 에어포일의 윗면에 다른 위치의 Hole이 있을 때와 크기가 다른 Hole이 있을 때의 실속각이 가장 커지는 경우를 찾아보았다. Hole의 위치와 반지름 크기를 변화시켰을 때 각각의 최대 양력 계수를 비교하여 실속각의 증가와 Streamline을 그려 유동박리가 지연됨을 확인하였다.

• Journal of Chest Surgery
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• v.37 no.10
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• pp.865-867
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• 2004

Development of intraoperative aortic dissection during coronary artery bypass surgery is extremely rare with catastrophic outcomes resulting in high rates of morbidity and mortality. The prognosis is highly dependant upon prompt diagnosis and emergent treatment. We report our experience on a 72 year old female patient who successfully received ascending aortic graft replacement for acute intraoperative aortic dissection during coronary artery bypass procedure.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.9-15
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• 2010

Numerical investigation was carried out on axisymmetric over-expanded rocket nozzle to predict flow fields of transitional shock separation patterns. The unsteady, compressible N-S equations with k-$\omega$ SST for turbulence model closure were solved using a fully implicit finite volume scheme. Computed results were in good agreement with previous experimental works. It was found that strong side-loads were generated during the transition of RSS to FSS due to the development of a vortex ring in the inviscid jet core region. Hysteresis phenomenon exhibited by the shock-separation patterns was also found during the start-up and shut-down processes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.319-325
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• 2018

Pot-holes are steadily increasing due to abnormal climate such as heavy rainfall and frequent snowfall. Pot-hole related to traffic accidents cause injuries, car damage and distress of road facilities. To reduce pot-holes, the use of an anti-stripping agent is mandatorily recommended to asphalt concrete mixture. Hydrated lime is commonly used as anti-stripping agent due to the convenience and economics. Byproduct ash from circulating fluidized bed boiler was reviewed as an anti stripping agent. According to the test results, the byproduct ash is satisfied with TSR specification using 1% to 3% by weight of the asphalt mixture. The byproduct ash was examined under various condition changes of aggregate and asphalt concrete mixture considering quality movement. According to the results, using the byproduct ash was measured average 0.87 of TSR and coverage rates of 60% after rolling bottle test. Test results also revealed that the byproduct ash showed stable performance. Using the byproduct ash to decrease pot-hole in asphalt concrete pavement is suitable for demonstrating stable performance as anti-stripping agent.

• Journal of Welding and Joining
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• v.8 no.1
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• pp.2-11
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• 1990

오-스테나이트계 스테인레스강을 용접육성한 강판의 박리균열의 원인에 대하여 강중의 수소거동을 중심으로 고찰해 보았다. 강중의 수소온도 분포를 추정하는데는 확산 방정식을 기초로하여 수치해석이 유력하며 그 기초적사항에 대해 제문헌을 인용하여 설명했으며, 또 시험편에 대하여 계산과 실험치의 결과를 이용하여 비교하였다. 이들로부터 박리균열의 발생에 대한 미시적 임계조건을 도출하여, 이들이 한정된 실험의 범위내이지만 실증할 수 있음을 나타내었다. 그러나 박리균열의 원인의 하나인 잔류응력에 대해서는 아직 불명한 점이 많으나, 냉각속도에 따라 변화하며 그것이 수소농도라고 하는 관점에서 미시적 임계조건에 영향을 미칠 수 있음을 시사하고 있다.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.210-212
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• 2001

Retinal detachment is a rare disease in children but cases of serous retinal detachment due to use of systemic corticosteroids have been reported in and out country Rhematogenous retinal detachment has developed in a child with oral and steroid pulse therapy due to nephrotic syndrome. He was treated with laser and buckling in right and left eye respectively. Currently he is under observation through the out patient department. (J. Korean Soc Pediatr Nephrol 2001 ; 5 : 210-12)

• Journal of Chest Surgery
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• v.39 no.7 s.264
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• pp.569-571
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• 2006

Intramural dissection of the esophagus is rare esophageal disorder which has been seen predominantly in women in their seventh or eighth decade and presents as acute chest pain, accompanied by dysphagia. The etiology of this disorder remain uncertain and the diagnosis is made by esophageal endoscopy, contrast esophagography, or both. Patient with this disorder is best managed conservatively with nothing by mouth and intravenous hydration.

• Journal of the Korean earth science society
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• v.22 no.6
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• pp.512-527
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• 2001

Separated flows passed complex geometries are modeled by discrete vortex techniques. The flows are assumed to be rotational and inviscid, and a new techlnique is described to determine the stream functions for linear shear profiles. The geometries considered are the snow cornice and the backward-facing step, whose edges allow for the separation of the flow and reattachment downstream of the recirculation regions. A point vortex has been added to the flows in order to constrain the separation points to be located at the edges, while the conformal mappings have been modified in order to smooth the sharp edges and to let the separation points free to oscillate around the points of maximum curvature. Unsteadiness is imposed to the flow by perturbing the vortex location, either by displacing the vortex from the equilibrium, or by imposing a random perturbation with zero mean to the vortex in equilibrium. The trajectories of passive scalars continuously released upwind of the separation point and trapped by the recirculating bubble are numerically integrated, and concentration time series are calculated at fixed locations downwind of the reattachment points. This model proves to be capable of reproducing the trapping and intermittent release of scalars, in agreement with the simulation of the flow passed a snow cornice performed by a discrete multi-vortex model, as well as with direct numerical simulations of the flow passed a backward-facing step. The results of simulation indicate that for flows undergoing separation and reattachment the unsteadiness of the recirculating bubble is the main mechanism responsible for the intense large-scale concentration fluctuations downstream.