• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1239-1244
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• 2014

In this study, two fiber-optic sensors were fabricated to measure water level and temperature using optical fibers, a coupler, a Lophine and an OTDR (optical time-domain reflectometer). First, using Fresnel's reflection generated at the distal-ends of each optical fiber, which was installed at different depth, we measured the water level according to the variation of water level. Next, we also measured the temperature of water using a temperature sensing probe based on the Lophine, whose absorbance changes with the temperature. The measurable temperature range of the fiber-optic sensor is from $5^{\circ}C$ to $65^{\circ}C$ because the maximum operation temperature of the optical fiber without a physical deterioration is up to $80^{\circ}C$.

• Electrical & Electronic Materials
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• v.16 no.9
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• pp.61.3-62
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• 2003

• Journal of Engineering Education Research
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• v.25 no.6
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• pp.14-22
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• 2022

This paper is a basic study of college of engineering freshmen's adaptation to college life, and the relationship between sub-variables of academic self-efficacy, learning immersion, and academic curiosity is analyzed. And based on the results, a plan to support new students of the College of engineering is suggested.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.71-74
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• 1990

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.71-74
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• 2005

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.76-79
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• 2003

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.80-82
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• 2003

• Structural Engineering and Mechanics
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• v.76 no.4
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• pp.551-559
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• 2020

On the basis of nonlocal strain gradient theory, considering the material properties of porous FGM changing with thickness and the influence of moment of inertia, the wave equation of FG nano circular plate is derived by using the first-order shear deformation plate theory, by introducing dimensionless parameters, we transform the equations into dimensionless wave equations, and the dispersion relations of bending wave, shear wave and longitudinal wave are obtained by Laplace and Hankel integral transformation method. The influence of nonlocal parameter, porosity volume fraction, strain gradient parameters and power law index on the propagation characteristics of bending wave, shear wave and longitudinal wave in FG nano circular plate.

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.176-177
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• 1999

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.414-415
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• 1999