• 소성∙가공
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• 제12권4호
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• pp.302-307
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• 2003

Hot rolled strip is cooled by air and water in Run-Out-Table. In this process, phase transformation and shape deformation occurs due to temperature drop. Because of un-ideal cooling condition of ROT, irregular shape deformation and phase transformation arise in the strip. which affect the strip property and lead to the residual stress of strip. And these exert effects on the following processes, coiling process, coil cooling process, and re-coiling process. Through these processes, the residual stress becomes higher and severe. For the prediction of residual stress distribution and shape deformation of final product, Finite element(FE) based model was used. It consists of non-steady state heat transfer analysis, elasto-plastic analysis. thermodynamic analysis and phase transformation kinetics. Successive FEM simulation were applied from ROT process to coil cooling process. In each process simulation, previous process simulation results were used for the next process simulation. The simulation results were matched well with the experimental results.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 추계학술발표대회 개요집
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• pp.213-215
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• 2004

Water jet propulsion system has high efficiency on middle to high speed, and it provides better safety than conventional screw propeller because it has not projected propeller and rudder. So many leisure boat and high-speed ferries use this propulsion system. We developed water-jet propulsion unit for small planning boat, and launched that in the boat, after that we tested water-jet unit in the lake. As a result, we certify heat dissipation at the bearing housing and reverse duct's shape for neutral position are important at the design, and alignment water-jet unit and keel line are important at the launching, and ship's resistance performance and jet's propulsion performance also are needed to consideration.

• 한국농공학회논문집
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• 제61권4호
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• pp.33-42
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• 2019

In this study, the channel and floodplain widths are indirectly measured for three different watersheds using satellite images to reflect the shape of Korean channels in the Soil and Water Assessment Tool (SWAT) model. For measuring the channel and floodplain widths, multiple satellite images were referred to ensure the widest width of certain points. In the single channel, the widths at the multiple points were measured. Based on the measured data, the regression equations were derived to estimate the channel and floodplain widths according to watershed areas. Applying these developed equations, this study evaluated the effect of the change of channel and floodplain widths on the SWAT simulation by comparing to the measured streamflow data. The developed equations estimated larger channel width and smaller floodplain compared with those calculated in the current SWAT model. As shown in the results, there was no considerable changes in the predicted streamflow using the current and developed equations. However, the flow velocity and channel depth calculated from the developed equations were smaller than those of the current equations. The differences were caused by the effect of different channel geometries used for calculating the hydraulic characteristics. The channel geometries also affected the water quality simulation in channels because the hydraulic characteristics calculated by the channel geometries are directly related to the water quality simulation. Therefore, application of the river cross-sectional regression equation reflecting the domestic stream shape is necessary for accurate water quantity / quality and water ecosystem simulation using hydrological model.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.100-103
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• 2005

This work discusses the numerical analysis, the design and experimental test of the SMA (Shape Memory Alloy) actuator along with its capabilities and limitations. Convection heating and cooling using water actuate the SMA element of the actuator. The fuel such as propane, having a high energy density, is used as the energy source for the SMA actuator in order to increase power and energy density of the system, and thus in order to obviate the need for electrical power supplies such as batteries. The system is composed of a pump, valves, bellows, a heater (burner), control unit and a displacement amplification device. The actuation frequency is compared with the prediction obtained from numerical analysis. For the designed SMA actuator system, the results of numerical analysis were utilized in determining design parameters and operating conditions.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.503-504
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• 2006

The MIM technology is an alternative process for fabricating near net shape components that usually uses gas atomised powders with small size $(<\;20\;{\mu}m)$ and spherical shape. In this work, the possibility of changing partially or totally spherical powder by an irregular and/or coarse one that is cheaper than the former was investigated. In this way, different bronze 90/10 components were fabricated by mixing three different types of powder, gas and water atomised with different particle sizes, in order to evaluate how the particle shape and size affect the MIM process.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.581-587
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• 2021

In recent years, contamination of drinking water sources has emerged as a serious social problem, such as a large number of impurities in tap water or groundwater or the supply of suitable water due to rust of pipes. Although the government and public institutions are implementing various measures to protect water sources, they cannot improve water quality in a short period of time because of the enormous cost involved. Therefore, in recent years, preference has been given to a device that converts tap water, which is hard water, into soft water by installing a separate water softener at the faucet from which tap water is discharged. However, the existing filtration device has a problem that filtration performance is gradually lowered when impurities accumulate in the filter, requiring continuous filter replacement. In this study, the optimal design of the filter housing was performed to develop a water softener that can be washed when impurities accumulate on the filter inside the water softener connected to the faucet. For optimal design of the filter housing, fluid and fluid-structural interaction analysis were performed on the design pressure to determine the shape and thickness of the housing, and design review was performed through prototype.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.174-177
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• 2003

The automatic temperature control valve is used to control the flow rate of heating water in the large apartment complex and buildings. It is important to have simillar heating flow rate in the apartments, even though the apartment is top or bottom floors. To achieve those purposes, the automatic flow-temperature control valve was developed. The perfromance of this control valve is effected by the catridge shape and spring length. The flow capacity of this control valve is obtained with the different shape of catridges and with change of spring length.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2146-2150
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• 2004

To evaluate the variation of spring stiffness in nuclear plant operating condition, load-displacement tests ($P-{\delta}$ test) were performed using two kinds of space grid springs in high temperature and high pressure water. With increasing temperature, stiffness of each spring gradually decreased except $100{\sim}150^{\circ}C$. It is apparently showed that spring with convex shape had a relatively high stability of spring stiffness at high temperature compared with I-shaped spring. It is suggested that the variation of spring stiffness with temperature and spring shape should be considered as an important variable in the design and analysis of the fuel assembly.

• 한국임상수의학회지
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• 제28권4호
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• pp.344-347
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• 2011

갈비연골속관절[늑연골속관절]은 우제류 갈비연골에 있는 윤활관절이다. 한국 고라니는 사슴과의 다른 동물과 다른 독특한 해부학적 구조를 지니고 있다. 그러나 한국 고라니 갈비연골속관절이 있는 곳과 그 형태에 관한 연구는 없다. 본 연구는 한국 고라니 갈비연골속관절에 대한 형태학적 자료를 제공하고자 육안관찰, 방사선사진 촬영, 컴퓨터 단층영상촬영(CT), 조직학적 관찰을 시행하였던 바, 갈비연골속관절은 주로 둘째에서 열째갈비연골에 이르기까지 존재하였으며 그 형태는 절구관절이었고, 이런 형태는 특히 셋째에서 여덟째 갈비연골속관절에서 뚜렷하였다. 이러한 결과는 한국고라니 가쪽가슴벽[외측흉벽]에 대한 진단과 처치에 도움을 줄 수 있을 것이다.

• 한국수자원학회논문집
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• 제47권4호
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• pp.307-319
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• 2014

최근 지구온난화 및 기후변화에 의한 재난이 빈발하고 있어 미국이나 네덜란드 같은 제방 선진국에서는 특수한 경우 적게는 500년, 크게는 10,000년 빈도의 홍수위까지도 고려하는 극단적인 수준의 제방설계기준을 적용하고 있다. 우리나라도 지난 몇 년간 국가하천을 중심으로 대하천 정비사업이 추진되었다. 주로 하천준설과 제방증축 및 신축 등으로 진행된 사업에 의해 하천환경이 광범위하게 변화되었으나 제방의 안전과 관련된 하천환경 변화에 대응하는 구체적인 대응방안을 제시하지는 못하고 있는 실정이다. 따라서 본 연구에서는 제방침투감지시스템 Testbed가 구축되어 있는 낙동강 회천의 율지제를 대상으로 제방 안전성을 평가하였다. 평가방법은 간극수압 계측자료를 이용하여 2차원 지하수 침투모형인 SEEP/W를 이용하여 제방의 파이핑 현상을 분석하였으며, 제방의 형상과 홍수파형에 따른 침투현상을 모의하여 제방안정성을 평가하였다.