• Journal of the Korea Institute of Building Construction
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• v.12 no.2
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• pp.230-242
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• 2012

Recently the Permanent Uni-wall System (PUS) has been developed which improved the disadvantage of the Cast-In-Place Concrete Pile (CIP) and could be used as permanent retaining wall. In this study, joints between PUS and floor systems were developed. From analyses of the characteristics of design and construction of PUS, shear friction reinforcements with couplers were adopted for shear design of the joints. Twelve types of joints were developed which were classified according to the types of floor structures, wale, and piles of PUS. Two typical joints were tested and the joints showed satisfactory behaviors on the points of shear strength, stiffness, and serviceability. Especially the shear strengths were much higher than the design strengths due to the shear keys which were by-products in splicing shear reinforcements. However, the shear strength of the joint is recommended to be designed by only shear friction reinforcement because shear key is not reliable and too brittle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.86-89
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• 2003

SBT thin film for semiconductor device that is made by RF magnetron sputtering method studied electrical properties under various temperature condition. Dielectric constant who differ annealing condition appears highest in $750[^{\circ}C]$ and it is 213. Also, C-V properties by annealing temperature of SBT thin film for semiconductor device is no change almost to $600[^{\circ}C]$ and shows non-linear butterfly shape more than $650[^{\circ}C]$ Maximum capacitance and difference of smallest capacitance show the biggest difference in $750[^{\circ}C]$ as degree that domain wall motion contributes in ferrelectric polarization value in C-V characteristic curve of ferroelectric that this shows typical ferroelectric properties. Therefore, SBT thin film for semiconductor device that is annealing in $750[^{\circ}C]$ expressed the most superior electrical and ferroelectric properties.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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• pp.819-827
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• 2006

The stress-strain relation of aluminum (Al) alloy foam cell wall was evaluated by the instrumented sharp indentation method. The indentation in a few micron ranges was performed on the cell wall of Al-alloy foam having a composition or Al-3wt.%Si-2wt.%Cu-2wt.%Mg as well as its precursor (material prior to foaming). To extract the stress-stram relation in terms of yield stress ${\sigma}_y$, strain hardening exponent n and elastic modulus E, the closed-form dimensionless relationships between load-indentation depth curve and elasto-plastic property were used. The tensile properties of precursor material of Al-alloy foam were also measured independently by uni-axial tensile test. In order to verify the validity of the extracted stress-strain relation, it was compared with the results of tensile test and finite element (FE) analysis. A modified cubic-spherical lattice model was proposed to analyze the compressive behavior of the Al-alloy foam. The material parameters extracted by the instrumented nanoindentation method allowed the model to predict the compressive behavior of the Al-alloy foam accurately.