• Journal of the Korean Magnetics Society
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• v.11 no.1
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• pp.32-37
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• 2001

Effects of steel-skeletons on the geomagnetic distribution in building have been studied through the simulation and measurement of geomagnetic distribution at floor surface. Geomagnetic distribution was simulated by the finite element method, and the vertical component Z of geomagnetic field on the floor surface was measured with the fluxgate-type magnetometer. Horizontal steel-skeletons have a little effect on the Z distribution, but vertical skeletons disturb severely the Z distribution and result in the localized geomagnetic disturbance. This disturbance becomes weakened by the bypassing soft-magnetic plate and/or floor.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.10-13
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• 2010

세그먼트 자중 등에 의한 휨모멘트와 케이블 수직압축력에 의한 합성응력이 발생되고 바닥판 경간비가 변하는 사장교의 시공단계에서는 전단지연의 영향범위가 다를 수 있다. 이 연구에서는 1면 케이블 콘크리트 박스 사장교를 대상으로 시공단계시 보강형에 고려되어야 할 합성응력에 의한 유효플랜지폭을 분석하였다. 그 결과 바닥판 경간비가 0.38 이하의 범위에서 보강형의 전폭을 유효플랜지폭으로 적용할 수 있는 것으로 해석되었다. 따라서 시공단계시 변화되는 바닥판 경간비의 크기에 관계없이 전폭을 유효플랜지폭으로 반영하는 실무관행은 안전측 설계가 되지 못할 수 가 있다. 바닥판 경간비가 작아짐에 따라서는 전폭과 캔틸레버 구조계로 유효플랜지폭을 결정하는 것이 타당하다. 이 연구에서는 수직력에 대한 도로교설계기준의 유효플랜지폭 규정에 대한 평가도 수행하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.275-281
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• 2011

To acquire an underwater topographic information is necessary for the design and construction of structures in marine and inland water. It consists of water depth information by bathymetric survey and underwater bottom topography image information can be obtained by side scan sonar in different ways. For the purpose of providing high quality data by means of engineering site survey, it is necessary to apply simultaneous acquisition of two information and carry out the integrated interpretation to each other. The present research aims to obtain information of the underwater topography and water depth at the same time using interferometer technique, and to validate interferometer technique with accuracy estimation.

• Korean Architects
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• no.4 s.157
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• pp.24-28
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• 1982

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.39-46
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• 2017

The experimental research was conducted to evaluate the adhesive performance of surface finishing material with primer based on silane(primer). For this purpose, concrete specimens with compressive strength of 18, 30, 50 MPa were made and cured in water condition ($20{\pm}2^{\circ}C$) for 28 days. A primer was applied on the age of 28 days and evaluated according to based on the curing age of the surface finishing material. Moreover, the mortar specimen also made and tested as per KS F 4937 for compared with concrete-based test results. Test results indicated that the adhesive strength of specimens with primer exhibit similar than that of specimens without primer. Also, the adhesive performance improved with increasing in curing age and compressive strength. The correlation between compressive and adhesive strength of mortar and concrete specimens showed similar trend. It was noted that there is no significant effects of primer on adhesive performance of surface finishing material, thus use of primer has superior potential for solving durability problem of concrete slab surface.

• Explosives and Blasting
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• v.37 no.4
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• pp.26-35
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• 2019

In designing a gravity-type anchorage of earth-anchored suspension bridge, the contact friction between a blasted rock mass and the concrete anchorage plays a key role in the stability of the entire anchorage. Therefore, it is vital to understand the shear behavior of the interface between the blasted rock mass and concrete. In this study, a portable 3D LiDAR scanner was utilized to scan the blasted bottom surfaces, and rock surface roughness was quantitatively analyzed from the scanned profiles to apply to 3D FEM modelling. In addition, based on the 3D FEM model, a three-dimensional dynamic fracture process analysis (DFPA-3D) technique was applied to study on the shear behavior of the interface between blasted rock and concrete through direct shear tests, which was analyzed under constant normal load (CNL). The effects of normal stress and the joint roughness on shear failure behavior are also analyzed.

• Composites Research
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• v.24 no.5
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• pp.29-33
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• 2011

The application of high performance materials for the deck can represent a fair alternative to reduce the weight of the deck and improve the econimic efficiency of the bridge even if high performance materials are costly. In UHPC(Ultra High Performance Concrete) bridges, it is necessary to verify that exiting headed stud can be used to transfer longitudinal shear forces across the steel-concrete interface. In this paper, the push-out tests are performed to analisys the composite behavior between UHPC bridge deck and steel girder. The ultimate strength of test specimens is proportional to the diameter of headed studs in push-out test for static loading. Test results show that the shear strength of headed stud is improved for the case of normal concrete bridge decks.

• Solar Energy
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• v.18 no.2
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• pp.115-121
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• 1998

In this study a channel cavity flow was performed. The channel has small size in the upper cavity region. At the gap is supplied by driven flow for Reynolds number. The experimental study was carried out in a channel cavity with square heat surface by visualization equipment with Mach-Zehnder interferometer and laser apparatus. Heat source was uniform heat flux($0.4W/cm^2,\;0.8W/cm^2,\;1.2W/cm^2$). When the bottom wall is heated, the tendency of natural convection flows are vigorous increasing heat flux.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.191-197
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• 2003

As mechanical components are miniaturized, the demand on micro die and mold is increasing. Micro mechanical components usually have high hardness and good conductivity. So micro electrical discharge machining (MEDM) is an effective way to machine those components. In micro cavity fabrication using MEDM, it is observed that the bottom surface of cavity is distorted. Electric charges tend to be concentrated at the sharp edge. At the center of the bottom surface, debris can not be drawn off easily. These two phenomena make the bottom surface of the electrode and workpiece distort. As machining depth increases, the distorted shape of electrode approaches hemisphere. This process is affected by capacitance and the size of electrode. By using a smaller electrode than the desired cavity size and appropriate tool movement, bottom shape distortion can be prevented.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.103-110
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• 2011

A two-dimensional immiscible droplet deformation phenomena on moving wall in a channel has been investigated by using lattice Boltzmann method involving two-phase model. The dependence of the deformation of the droplet with different sizes on the contact angle and the velocity of bottom wall has studied. When the bottom wall starts to move, the deformation of the droplet occurs. For the largest bottom wall velocity, eventually, the deformation of the droplet is classified into the three patterns according to the contact angle.