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Lee, Jae-Yun;Yang, Ji-Hun;Kim, Geun-Hyeong
- Proceedings of the Korean Institute of Surface Engineering Conference
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- 한국표면공학회 2018년도 춘계학술대회 논문집
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- pp.24-24
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- 2018
One of the challenges in tissue engineering is the design of optimal biomedical scaffolds, which can be governed by topographical surface characteristics, such as size, shape, and direction. Of these properties, we focus on the effects of nano - to micro - sized hierarchical surface. To fabricate the hierarchical surface structure on poly(${\varepsilon}$-caprolactone) (PCL) film, we employed a nano/micro-casting technique (NCT) and modified plasma process. The micro size topography of PCL film was controlled by sizes of the micro structures on lotus leaf. Also, the nano-size topography and hydrophilicity of PCL film were controlled by modified plasma process. After the plasma treatment, the hydrophobic property of the PCL film was significantly changed into hydrophilic property, and the nano-sized structure was well developed, as increasing the plasma exposure time and applied power. The surface properties of the modified PCL film were investigated in terms of initial cell morphology, attachment, and proliferation using osteoblast-like-cells (MG63). In particular, initial cell attachment, proliferation and osteogenic differentiation in the hierarchical structure were enhanced dramatically compared to those of the smooth surface.
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Ha, Jong-Hak;Kim, Seong-Soo;Wang, Lin;Choi, Hee-Kyu
- Korean Journal of Materials Research
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- 제18권3호
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- pp.128-136
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- 2008
Evaluation of the solid surface properties by an analysis of the liquid penetration rate into powder beds is very important in applications of powder products. The penetration rate is related the surface property in powder beds. In order to analyze the surface property of powders, the contact angle values of several powders were obtained using the Washbun equation and the Wicking method. The surface free energy value ${\gamma}S$ was divided into a polar component ${\gamma}S^p$ and a dispersion component ${\gamma}S^d$. Inorganic powders such as calcite were used as test samples. The effects of the particle size and the type of experimental liquid on the penetration rate were measured. It was confirmed that the surface free energy of the grinding sample is smaller than that of the classification sample.
https://doi.org/10.3740/MRSK.2008.18.3.128 인용 PDF KSCI

남기천;이진무;차성수
- Tunnel and Underground Space
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- 제5권3호
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- pp.214-222
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- 1995
Geological events which are undetected by the surface geophysical or geological survey phase can cause many problems, especially when the tunnel is excavated by TBM. To detect the geological events ahead of tunnel face, a seismic method applied from VSP method is used. Generally uniaxial geophone has been used in surface seismic survey. But this time, triaxial geophone is used to reduce the noise of tunnel wave. DME(Dip moveout Enhancement) filter and diffraction stack method are used. Applying these techniques to the road tunnel in construction, it is proved that the geological events ahead of tunnel face is fairly well predicted. From the seismic trace, Vp and Vs which are related to the rock property can be also obtained. Rock property and proper support design can be dedced from these parameters.
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