• 대한토목학회논문집
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• 제34권1호
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• pp.167-173
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• 2014

석션 매입 앵커(Embedded Suction Anchor; ESA)는 석션 기초(Suction Pile or Caisson)을 이용하여 앵커를 지중에 매설한 후 인발에 저항하는 계류앵커형식이다. 본 연구에서는 ALE (Arbitrary Larangan Eulerian) Adpative Meshing 기법을 이용한 수치해석을 통해 석션 매입 앵커의 인발 거동을 모사하고, 그 결과를 기존 연구에서 수행된 원심모형 실험 및 한계 평형법을 이용한 해석적 방법의 결과와 비교 분석 하였다. 이를 통해 앵커의 수평 연직 경사 방향의 인발 거동을 평가하였으며, 수치 해석 결과, 수평 재하 시 중간 위치에서 가장 큰 저항력을 발휘하는 것으로 나타났다. 연직 재하의 경우 재하 위치와 무관하게 유사한 저항력이 발휘 되었으며, 수평 저항력이 가장 큰 중간 위치에서 경사 하중을 가한 결과 경사각이 증가할수록 인발 저항력이 감소하는 것으로 나타났다.

• 한국해양환경ㆍ에너지학회지
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• 제10권4호
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• pp.218-226
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• 2007

본 연구는 생존성 측면에서 잠수함의 내충격 설계시 고려해야 하는 수중폭발 충격응답해석 기법에 관하여 고찰하였다. 생존성을 고려하는 것은 현대의 모든 함정설계에 필수요건이며, 특히 잠수함의 수중폭발에 대한 내충격 설계는 반드시 고려되어야 할 사항이다. 기존의 수중함에 대한 내충격 설계는 가정된 이론에 의한 충격가속도를 정적해석의 결과를 통하여 단순하게 적용하였으나 본 연구에서는 직접해석법에 수중폭발 충격응답해석을 수행함으로써 기존의 방법보다 매우 합리적이고 신뢰성 높은 결과를 제시하였다. 특히 본 연구에서는 직접해석법 중에서 기존 수상함에서 널리 사용하고 있는 LS-DYNA/USA code일 적용보다 LS-DYNA code만으로 사용자가 보다 손쉽게 접근할 수 있는 ALE기법을 이용하여 잠수함 액화산소탱크를 대상으로 수중폭발해석 방식을 제안하고자 하였다.

• 한국분말재료학회지
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• 제30권1호
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• pp.53-64
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• 2023

Atomic layer etching (ALE) is a promising technique with atomic-level thickness controllability and high selectivity based on self-limiting surface reactions. ALE is performed by sequential exposure of the film surface to reactants, which results in surface modification and release of volatile species. Among the various ALE methods, thermal ALE involves a thermally activated reaction by employing gas species to release the modified surface without using energetic species, such as accelerated ions and neutral beams. In this study, the basic principle and surface reaction mechanisms of thermal ALE?processes, including "fluorination-ligand exchange reaction", "conversion-etch reaction", "conversion-fluorination reaction", "oxidation-fluorination reaction", "oxidation-ligand exchange reaction", and "oxidation-conversion-fluorination reaction" are described. In addition, the reported thermal ALE processes for the removal of various oxides, metals, and nitrides are presented.

• 한국식품과학회지
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• 제40권2호
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• pp.238-242
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• 2008

Ale과 lager 효모를 이용하여 맥주발효 실험한 결과, lager 효모는 발효가 활발하게 일어나는 발효 초기에 많은 양의 황화수소를 발생하였으며 ale 효모보다 더욱 많은 양의 황화수소가 발생되었다. 효모의 증식이 활발한 발효 초기에 많은 양의 황화수소가 만들어지는 것을 보아 효모의 증식과 황화수소의 생성 사이에는 상관관계가 있음을 확인하였다. 온도 차이에 따른 실험 결과에서, lager 효모의 경우에는 발효 온도가 높은 것이 발효율이 더 높아 발효 시간을 줄일 수 있는 장점은 있으나, 많은 양의 황화수소가 발생되는 것을 알 수 있었다. 또한 APL은 $15^{\circ}C$에서 발효시켰을 때, 발효 끝 부분에서 많은 양의 황화수소가 발생되었는데, 이것은 맥주에 좋지 않은 냄새의 원인이 되므로 장시간의 숙성기간을 필요로 한다는 것을 의미한다. EA의 경우에는 낮은 온도에서 오히려 더 많은 양의 황화수소가 생성이 되었으나, HA의 경우에는 lager 효모에서와 같이 높은 온도에서 더 많은 양의 황화수소가 생성되었는데, 이는 각 효모마다 $H_2S$를 생성하기에 적합한 온도가 있음을 의미한다.

• Food Science and Biotechnology
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• 제15권5호
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• pp.752-755
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• 2006

This study was carried out to investigate the effects of ash tree leaf extract (ALE) on acetaminophen (APAP)-induced hepatotoxicity in mice. Hepatoprotective effects were detected by biochemical analysis of hepatic enzymes and histopathological examination of the liver. BALB/c mice were divided into three groups: 'normal' control mice, APAP-treated control mice, and mice pretreated with ALE and treated with APAP. A single dose of APAP markedly increased levels of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Light micrographs of liver cells stained with hematoxylin and eosin showed that APAP induced severe centrilobular necrosis, degeneration, and infiltration by inflammatory cells. Moreover, APAP caused the numbers of TUNEL-positive hepatocytes to increase and caused glycogen content to decrease as observed by Periodic acid-Schiff stain. However, pretreatment with ALE for 7 days prior to the administration of APAP significantly decreased plasma levels of AST and ALT. Histological findings demonstrated that ALE pretreatment alleviated APAP-induced liver damage, and induced the regeneration of liver tissue and restoration of glycogen. These results indicate that ash tree leaf extract exerts a protective effect against APAP-hepatotoxicity induced injury.

• 대한조선학회논문집
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• 제42권4호
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• pp.330-340
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• 2005

Compressible two-phase flow is analyzed based on the arbitrary Lagrangian-Eulerian (ALE) formulation. For water, Tamman type stiffened equation of state is used. Numerical fluxes are calculated using the ALE two-phase Godunov scheme which assumes only that the speed of sound and pressure can be provided whenever density and internal energy are given. Effects of the approximations of a material interface speed are Investigated h method Is suggested to assign a rigid body boundary condition effectively To validate the developed code, several well-known problems are calculated and the results are compared with analytic or other numerical solutions including a single material Sod shock tube problem and a gas/water shock tube problem The code is applied to analyze the refraction and transmission of shock waves which are impacting on a water-gas interface from gas or water medium.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.247-250
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• 2007

Flexible media such as the paper, the film, etc. are thin, light and very flexible. They behave in geometrically nonlinear. Any of small force makes large deformation. So we must including aerodynamic effect when its behavior is predicted. Thus, it becomes fully coupled fluid-structure interaction(FSI) problem. In FSI problems, where the fluid mesh near the structure undergoes large deformations and becomes unacceptably distorted, which drive the time step to a very small value for explicit calculations, the arbitrary Lagrangian-Eulerian(ALE) methods or rezoning are used to create a new undistorted mesh for the fluid domain, which allows the calculations to continue. In this paper, FE sheet model considering geometric nonlinearity is formulated to simulate the behavior of the flexible media. Aerodynamic force to the media by surrounding air is calculated by solving the incompressible Navier-Stokes equations. Q2Q1(Taylor-Hood) element which means biquadratic for velocity and bilinear for pressure is used for fluid domain. Q2Q1 element satisfies LBB condition and any stabilization technique is not needed. In this paper, cantilevered sheet in the viscous incompressible Navier-Stokes flow is simulated to check the mesh motion and numerical integration scheme, and then falling paper in the air is simulated and the effects of some representative parameters are investigated.

• 대한기계학회논문집B
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• 제23권1호
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• pp.43-57
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• 1999

The fluid flow and heat transfer in a thin liquid film are investigated numerically. The flow Is assumed to be two-dimensional laminar and surface tension is considered. The most important characteristics of this flow is the existence of a hydraulic jump through which the flow undergoes very sharp and discontinuous change. Arbitrary Lagrangian-Eulerian(ALE) method is used to describe moving free boundary and a modified SIMPLE algorithm based on streamline upwind Petrov-Galerkin(SUPG) finite element method is used for time marching iterative solution. The numerical results obtained by solving unsteady full Navier-Stokes equations are presented for planar and radial flows subject to constant wall temperature or constant wall heat flux, and compared with available experimental data. It Is discussed systematically how the inlet Reynolds and Froude numbers and surface tension affect the formation of a hydraulic jump. In particular, the effect of temperature dependent fluid properties is also discussed.

• 한국표면공학회지
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• 제24권1호
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• pp.1-17
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• 1991

Understanding of the detailed reaction mechanisms during MOVPE and ALE is essential to further improve the properties of the grown crystals and the controllability of the growth parameters. The unified models for the detailed reaction paths are not available at this stage. The study, however, has been advanced to the extent that consensus on some of the reaction paths can be drawn from the scattered data. Metalakyls such as TMGa and TMIn seem to nearly fully decompose in the gas phase through homogeneous reaction at the typical MOVPE growth temperature. Hydrides such as AsH3 and PH3, on the contrary. seem to decompose heterogeneously onthe substrate surfaces as well as homogeneously in the gas phase. However, at lower temperatures, where ALE crystals are typically grown, the growth process is strongly dependent on the surface reactions. It seems that steric hindrance effects which the radicals reaching the substrate exhibit on the surface the growth rate a function of the metalalkyle supply durations. In addition, dydrogens released from hydrides seem to play an essential role in removing carbons leberated from the metalalkyls. High growth temperatures also seem to be effective in desorbing carbons from surface. The understanding of the reaction mechanisms was possible though diverse appraaches utilizing many ex-situ and in-situ diagnostic techniques and genuine experimental designs. It is the purpose of this paper to review and discuss many of these efforts and to draw some possible conclusions from them.

• 한국표면공학회지
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• 제24권1호
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• pp.1.1-1.1
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• 1991

Understanding of the detailed reaction mechanisms during MOVPE and ALE is essential to further improve the properties of the grown crystals and the controllability of the growth parameters. The unified models for the detailed reaction paths are not available at this stage. The study, however, has been advanced to the extent that consensus on some of the reaction paths can be drawn from the scattered data. Metalakyls such as TMGa and TMIn seem to nearly fully decompose in the gas phase through homogeneous reaction at the typical MOVPE growth temperature. Hydrides such as AsH3 and PH3, on the contrary. seem to decompose heterogeneously onthe substrate surfaces as well as homogeneously in the gas phase. However, at lower temperatures, where ALE crystals are typically grown, the growth process is strongly dependent on the surface reactions. It seems that steric hindrance effects which the radicals reaching the substrate exhibit on the surface the growth rate a function of the metalalkyle supply durations. In addition, dydrogens released from hydrides seem to play an essential role in removing carbons leberated from the metalalkyls. High growth temperatures also seem to be effective in desorbing carbons from surface. The understanding of the reaction mechanisms was possible though diverse appraaches utilizing many ex-situ and in-situ diagnostic techniques and genuine experimental designs. It is the purpose of this paper to review and discuss many of these efforts and to draw some possible conclusions from them.