• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.766-771
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• 2001

The package used to transport radioactive materials, which is called by cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than one for test. the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors. the results depends on how users apply the codes and it can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop and the puncture condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique for the free drop impact test of the cask and found several vulnerable cases to errors. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• 수산해양기술연구
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• 제17권2호
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• pp.109-113
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• 1981

Most existing theories on ship waves and wave resistance are based on the perturbation of the flow field by a small pararr.eter which specifies the slenderness of the ship hull. Since however, ship hulls in practice are neither so slender nor thin enough to secure the validity of the linearized theory, the agreen:ent between the theoretical prediction and the experimental result is not generally satisfactory. The author pointed out that the contribution by the non-linear term in the free surface condition can be represented by sorr.e source distribution over the still water plane. This paper leads to a forrr.ula for the wave resistance of not slender ships at low Froude nurr.bers. and deals with the asynptotic expression. As a nurr.erical example, the wave resistance of Wigley model is calculated, and the result is compared with experimental values. It is concluded that the wave resistance coefficient varies in the rate of Fn6 at low speed limit in general. A comparison with the result derived from the linearized free surface condition shows that the non-linearity of the free surface is irr portant at low speed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2011년도 춘계학술대회
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• pp.7-9
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• 2011

In December 2002, International Maritime Organization (IMO) has adopted the Resolution MSA.137(76) Standards for the Ship Maneuverability. For applying the standards, we have to estimate and evaluate the Maneuverability of a ship at the design stage in difference of trim and displacement as accurate as possible. In this paper, the effect of loading condition on the ship Maneuverability was investigated through 3 methods : numerical simulation, free running model ship and real ship data.. Firstly, We carried out numerical simulation, free running model ship experiments and real ship experiments at ballast condition, half loaded condition and full loaded condition with difference of trim.. Secondly, by comparing these results of 3 methods, we draw out the trend of ship Maneuverability due to the change of trim and displacement of a ship.

• 한국정밀공학회지
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• 제26권7호
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• pp.112-119
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• 2009

The purpose of this study is to evaluate the evaluation of process yield performed by using Sn & Cu treatment on the surface to optimize process condition for Lead-free solder application. The materials which are used for the New Surface Treatment study are Semi-Dulling plating for high speed Sn/Cu alloy of Soft Alloy GTC-33 Pb free known as "UEMURA Method" and plating substrate is alloy 42.Especially in lead-free plating process, it is important to control plating thickness and Copper composition than Sn/Pb plating. Evaluated and controlled plating thickness $12{\pm}3um$, Copper composition $2{\pm}1%$, plating particle and visual inspection. The optimization of these parameters and condition makes it makes possible to apply Sn/Cu Lead-free solder from Sn/Pb alloy.

• 전산구조공학
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• 제10권3호
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• pp.185-193
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• 1997

탄성 선형 경화 재료로 구성된 복합 구조물의 자유 경계면에서 나타나는 응력 특이도를 평면 변형률 상태에서 계산하였다. 자유 표면력 경계조건과 계면 연속조건을 만족해야하는 지배 탄성 방정식은 2점 경계치문제로 정의되며, 일반 고유치 문제의 해인 고유치가 응력 특이도가 될 것이다. 자유경계면 근처에서 응력 성분을 r/sup s-1/에 비례한다고 가정하여 특정한 s(고유치)를 구하는 고유치 문제를 뉴톤향상법과 사격법을 사용하여 수치적으로 해를 구하였다.

• 한국전산유체공학회지
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• 제21권1호
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• pp.110-116
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• 2016

The present study numerically investigated the deformation of the interface of two-phase fluids flow in a blast furnace. To simulate three-dimensional(3D) incompressible viscous two-phase flow in the furnace filled with the air and molten iron, the volume of fluid(VOF) method based on the finite volume method has been utilized. In addition, the porous medium with the porosity has been considered as the bed of the particles such as cokes and char etc. For the comparison, the single phase flow and the two-phase flow without the porosity have been simulated. The two-phase flow without porosity condition revealed the smooth parabolic profile of the free surface near the outlet. However, the free surface under the porosity condition formed the viscous finger when the free surface was close to the outlet. This viscous finger accelerated the velocity of the free surface falling and the outflow velocity of the fluids near the outlet.

• 한국항공우주학회지
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• 제39권2호
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• pp.97-105
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• 2011

본 논문에서는 균일 열부가 하중을 받는 사각판의 자유 진동특성을 중첩법에 의한 수치해석과 유한요소 해석을 통하여 연구하였다. 사각판의 재질은 알루미늄, 강재 및 스테인레스강 이다. 부가한 온도 조건은 상온에서부터 $300^{\circ}C$까지 부가하였고, 경계조건은 자유-자유 조건이다. 완전 대칭 모드, 완전 역대칭 모드 및 대칭-역대칭 모드에 대한 해석이 수행되었다.

• Archives of Reconstructive Microsurgery
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• 제8권1호
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• pp.35-43
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• 1999

저자들은 1988년부터 1998년까지 시행한 252예의 유리피판술 중 9예에서 미세혈관 문합부의 혈전 등의 이유로 실패하였으며, 이들 중 두경부 및 하지의 7예에서는 첫 수술 4-16일 사이에 제 2의 유리피판술을 성공적으로 시행하여 환부를 치유시키고, 처음에 계획하였던 수술적 목표를 달성하였다. 수부의 2예는 환자 및 보호자와 충분한 상의하여 원거리 피판과 피부이식 등 고식적인 치료 방법을 선택하였다. 수부의 경우는 다른 부위보다 고식적 치료 방법이 덜 부담되었던 것으로 생각되었으며, 두경부와 하지는 환부의 특성상 제 2의 유리 피판술이 최선의 선택으로 생각되었다. 유리 피판술이 실패한 환부에서 계속된 제 2의 유리 피판술을 시행하는 것은, 처음의 수술보다 면밀한 술전 계획과 준비, 완벽한 수술, 수술후의 철저한 환자 관리가 요구되었으나, 이들 환부의 처치에 매우 효과적이고 환자의 기대에 부응할 수 있는 방법이라고 생각된다.

• 한국전산유체공학회지
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• 제4권1호
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• pp.19-26
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• 1999

This paper describes a numerical method for predicting the incompressible unsteady laminar three-dimensional flows with free-surface. The Navier-Stokes equations governing the flows have been discretized by means of finite-difference approximations, and the resulting equations have been solved via the SIMPLE-C algorithm. The free-surface is defined by the motion of a set of marker particles and the interface behaviour was investigated by means of a "Lagrangian" technique. Using the GALA concept of Spalding, the conventional mass continuity equation is modified to form a volumetric or bulk-continuity equation. The use of this bulk-continuity relation allows the hydrodynamic variables to be computed over the entire flow domain including both liquid and gas regions. Thus, the free-surface boundary conditions are imposed implicitly and the problem formulation is greatly simplified. The numerical procedure is validated by comparing the predicted results of a periodic standing waves problems with analytic solutions. The results show that this numerical method produces accurate and physically realistic predictions of three-dimensional free-surface flows.

• 한국수소및신에너지학회논문집
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• 제17권1호
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• pp.1-7
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• 2006

The free-piston hydrogen fueled engine is estimated as the next generation power system which can obtain high efficiency and low emission, simultaneously. In order to develop the free-piston hydrogen fueled engine, it is necessary to stable the combustion. The engine combustion, backfire and knock phenomenons were studied by using RICEM for researching combustion characteristics of free-piston engine. As the results, backfire occurrence was not observed in the free-piston engine under limited experimental condition. And knocking occurred in case of higher cylinder wall temperature.