• Journal of Conservation Science
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• v.28 no.4
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• pp.329-341
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• 2012

Magai Wareiishi Jizo (Buddhist statue carved on rock surface) is close to shoreline and a part of rock block is periodically immersed by seawater. Rock material of the Wareiishi-jizo statue is composed mainly of medium or coarse-grained biotite granite and very durable. However, physical properties of the rock have been changed according to the complex interactions of the salt solution and surrounding environment. Exfoliation of the rock surface is a serious condition by salt crystallization. Exfoliation (14.6%) is concentrated on the upper part of the rock block with mainly boundary of seawater as the center. On the other hand, lower part of the rock block show black layers by contaminants deposition. In addition, brown discoloration and biological contaminants is overlapped. Rock surface show high discoloration rate of 50.5% (black discoloration, 29.2% > yellow discoloration, 14.1% > brown discoloration, 4.4% > green discoloration, 2.9%). Upper part of the rock block had a lot of change in the physical properties than lower part that is immersed by seawater. In particular, surface properties of the rock block was very weak state at the boundary surface of seawater permeation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1039-1048
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• 2018

In urban tunnel construction, most of the Shield TBM method is applied to secure the safety of buildings and to minimize risks. On the other hand, in the urban development process, landfills are often embanked or improving in many cases, so that the boundary between the surface and the rock is often heterogeneous. In case of ground condition such as alluvial soil, granite, decomposed granite, core stone and rock with various layers, datas on shield TBM advancing according to each ground condition are analyzed, The characteristics of machine load were compared and analyzed. As a result, it can be predicted that the change of ground condition can be predicted by the tendency of discharge volume, thrust force and cutting wheel torque when the cutter is checked and replaced regularly on advancing under maintaining the design slurry pressure.

• Journal of Korea Water Resources Association
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• v.45 no.5
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• pp.465-472
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• 2012

Recently, as the development of water front and natural type river is gradually increasing, it is mostly the case in that the flow analysis is implemented by only the flood level of the starting point without the tidal effect when the flood water level of the starting point is highly estimated than the high tidal water level in the design of river adjacent to an estuary. This research has analyzed the variation of tidal current for Oncheon river in Busan using Delft-3D program, considering that the tidal effect can cause the change of the flood water level of the starting point although the flood water level is higher than the flood tide level. As a result, considering the tidal effect at downstream boundary condition, water level indicates a periodicity of tide in particular region and the fluctuation range of water level is extended to upstream.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.135-136
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• 2016

SUPER concrete poontoon is developed to overcome shortcomings about corrosion problem of steel pontoon and the insufficient freeboard line of concrete pontoon. Top slab of Pontoon resists truck load or sidewalk live load. The soffit slab and outer wall of Pontoon resist the horizontal and vertical components of wave pressure, and those were loaded along X and Y-axis of Pontoon. Global analysis for the Pontoon is carried out to design its cross-sections economically using a geometric non-linear time history analysis method by Strand7 and buoyance-stability calculated automatically on non-vertical boundary conditions. And the load-capacity of Pontoon is confirmed through mock-up tests.

• Journal of Chest Surgery
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• v.34 no.5
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• pp.386-392
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• 2001

배경: 기관지에 광범위한 협착을 가지고 있는 환자들에게서 협착된 기관지 이하 부위에 있는 폐를 절제하지 않고 기관지 협착 부위를 교정하여 폐환기를 원할하게 하고자 하는 다양한 술식의 기관지 성형술이 고안시도되어 왔지만 만족할만한 술기는 아직 정립되어 있지 않다. 저자들은 이러한 기관지 협착을 교정하기 위한 술식의 하나로서 기관지 대치물을 이용한 기관 성형술의 효과를 조사하기 위하여 본 실험을 시행하였다. 대상 및 방법: 기관지 대치물로 사용한 두 종류의 첨포에 따라 성숙견을 실험 동물로 하여 두 군으로 분류하였으며 A군(5예)에서는 좌측 주기관지 전측방 부위를 0.5$\times$0.5cm 크기의 직사각형으로 절제한 후 늑연골에 자가 심낭편을 댄 동일한 크기의 첨포를 절제 부위에 부착하였고 B군(5예)에서는 동일한 크기의 기관지 절제 부위에 glutaraldehyde로 처리된 우심낭편을 부착하였다. 첨포를 이용한 기관지 성형술 12주후에 실험견을 도살하고 육안적 및 현미경적으로 관찰하였다. 결과: A군이 기관지 성형술 부위에서는 첨포의 외면은 주위의 결합조직과 막상유착을 이루고 있었으며 첨포의 가장자리는 자가 기관지에 잘 부착되어 있었다. 기관지 내면은 내경의 협착이 없이 윤기 있는 점막으로 잘 유지되어 있었고 자가 기관지와 첨호와의 경계면은 신생육아조직이 일부 차지하고 있었으며 새로운 이행 상피가 가교를 이루고 있는 현미경적 소견을 보았다. B군의 기관지 성형술 부위에서는 첨포의 와부는 암갈색으로 변화된 부분적 괴사의 양상을 보였다. 기관지 내면은 첨포와 가자기관지 경계부위에서 염증성 육아조직과 부분적 출현 양상을 보고 기관지 내경의 일부가 수축되었으며 자가 기관지로부터 첨포내로의 새로운 상피 형성은 되어 있지 않았다. 결론: 늑연골에 자가 심낭편을 댄 첨포는는 자가 기관지와 상피 가교를 형성하고 기관지 내강의 협착이 없이 구조를 유지하므로 기관지 협착 및 결손의 치료를 위한 기관지 성형술시에 기관지 대치물로 사용될수 있는 것으로 사료된다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.1-9
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• 2003

Detailed flow of a shrouded tail rotor in hover is studied by using a compressible inviscid flow solver on unstructured meshes. The numerical method is based on a cell-centered finite-volume discretization and an implicit Gauss-Seidel time integration. Numerical simulation is made for a single blade attached to the center body and guide by the duct by imposing a periodic boundary condition between adjacent rotor blades. The results show that the performance of an isolated rotor without shroud compares well with experiment. In case of a shrouded rotor, correction of the collective pitch angle is made such that the overall performance matches with experiment to account for the uncertainties of the experimental model configuration. Details of the flow field compare well with the experiment confirming the validity of the present method.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.3
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• pp.53-60
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• 1997

Generally, a safety estimation based on the buckling strength is carried out to evaluate the strength of plate members in the design process of ship hull structures and more accurate and efficient tool for the buckling strength estimation of enormous plate members of ship structure is naturally demended for saving design process. While, in the reason that the design codes of classification societies do not consider the various effects or include some effects roughly, considerate safe side results are suggested occasionally. In this study, advanced buckling strength estimation system prepared various classification buckling evaluation codes and new evaluation code considering the effects of in-plane tension, plate boundary condition, lateral load & residual stress is developed using the window management system of engineering workstation. Additionally maximum deflection estimation formula is equipped for the increase of fabrication reliability of thin plate ship structure. From this evaluation system, more reliable buckling safety of plate panel will be guaranteed in the ship hull design stage. In order to expand the use of this system pc version system will be developed sooner or later.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.555-561
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• 1995

This paper examines the applicability of the modified Borresen's coarse-mesh method(MBSN) to the core power distribution monitoring program development for the Yonggwang nuclear power plant unit 3(YGN 3) which uses fixed incore detectors for monitoring core power distribution. In so doing the modified Borresen's coarse-mesh equations are solved with core internal boundary conditions provided by the fixed incore detectors and three-dimensional core power distributions are com puted for the first-cycle core of the YGN 3 PWR. The results are compared with predictions of the COLSS(Core Operating Limit Supervisory System) which is the axial power shape monitoring program of the YGN 3. It is shown that the modified Borresen's method can reproduce the core axial power shape more closely than the COLSS. Because of other advantages in computing speed and predictive capability, n conclude that the proposed MBSN has a promising practical application for core power distribution monitoring program development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.399-406
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• 2016

The large scale wind turbine blades usually experience periodic change of inflow speed due to blade rotation inside the ground shear flow region. Because of the vertical wind shear, the inflow velocity in the boundary layer region is maximum at uppermost position and minimum at lowermost position. These spatial distribution of wind speeds can lead to the periodic oscillation of the 6-component loads at hub and low speed shaft of the wind turbine rotor. In this study we compare the aerodynamic loads between two inflow conditions, i.e, uniform flow (no vertical wind shear effect) and normal wind profile. From the computed results all of the relative errors for oscillating amplitudes increased due to the ground shear flow effect. Especially bending moment and thrust at hub, and bending moments at LSS increased enormously. It turns out that the aerodynamic analysis including the ground shear flow effect must be considered for fatigue analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.656-663
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• 2007

In this paper, when a E-polarized plane wave is incident on the grating consisting of tapered resistive strips, electromagnetic scattering is analyzed using the method of moments(MoM). The induced current density of each resistive strip in a grounded double dielectric layer is expected to blow up at both edges. To satisfy this, the induced surface current density is expanded in a series of Chebyshev polynomials of the second kind. The scattered electromagnetic fields are expanded in a series of Floquet mode functions. The boundary conditions are applied to obtain the unknown current coefficients. According to the variation of the involving parameters such as strip width and spacing and angle of the incident field, numerical simulations are performed by applying the Fourier-Galerkin moment method. The numerical results of the normalized reflected power for resistive strips case for several resistivities are obtained.