• Proceedings of the Materials Research Society of Korea Conference
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• 2006.11a
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• pp.16.1-16.1
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.632-635
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• 2003

As a process technology of nano pattern with a new conception for economic and practical technology of alternative nano process. process technologies such as Embossing, Imprinting. Molding and Inking are beginning to make its appearance. Among these alternative processes, nano mold process is a process that is of benefit to mass production and keeps excellency of reproduction and high quality of parts. In this study, we experienced micro precision machining technology of nano stamper for the injection mold of optical disk with big capacity. Especially, Flatness and uniformity are important for nano stamper with global area, for the purpose of developing polishing technology of micro precision of Back polishing only being used for nano stamper, we carried out a basic study to secure flatness standards

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1139-1143
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• 2007

A simple method for the fabrication of 3D micro-nano hybrid patterns was presented. In conventional fabrication methods of the micro-nano hybrid patterns, micro-patterns were firstly fabricated and then nano-patterns were formatted on the micro-patterns. Moreover, these micro-nano hybrid patterns could be fabricated on the flat substrate. In this paper, we suggested the fabrication method of 3D micro-nano hybrid patterns using micro-indentation on the anodized aluminum substrate. Since diameter of the hemispherical nano-pattern can be controlled by electrolyte and applied voltage in the anodizing process, we can easily fabricated nano-patterns of diameter of loom to 300nm. Nano-patterns were firstly formatted on the aluminum substrate, and then micro-patterns were fabricated by deforming the nano-patterned aluminum substrate. Hemispherical nano-patterns of diameter of 150nm were fabricated by anodizing process, and then micro-pyramid patterns of the side-length of $50{\mu}m$ were formatted on the nano-patterns using micro-indentation. Finally we successfully replicated 3D micro-nano hybrid patterns by hot-embossing process. 3D micro-nano hybrid patterns can be applied to nano-photonic device and nano-biochip application.

• Transactions on Electrical and Electronic Materials
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• v.14 no.1
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• pp.1-8
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• 2013

The present approach shows the use of nano-silica/nano-alumina in polyurethane (PU) matrix, which lead to significant improvements in the mechanical and thermal properties of the nano-composite. It is observed that with incorporation of 1% of nano-alumina into the PU matrix, there is an improvement in the tensile strength of around 50%, and for nano-silica the improvement is around 41%, at the same concentration. The morphological data shows that above 3% of the nano particles there are agglomerations in the nanocomposite. Again with the absorption of moisture, there is a decrease in the thermal and mechanical properties of the PU resin, but in this research work it is observed that with the incorporation of the nano particles, in the presence of absorbed moisture there is an improvement in mechanical and thermal properties of the composite, over that of the PU matrix.

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.11a
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• pp.14.1-14.1
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• 2006

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.05a
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• pp.21.1-21.1
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.156-162
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• 2006

Direct fabrication of nano patterns has been studied employing a nano-stereolithography (NSL) process. The needs of nano patterning techniques have been intensively increased for diverse applications for nano/micro-devices; micro-fluidic channels, micro-molds. and other novel micro-objects. For fabrication of high-aspect-ratio (HAR) patterns, a thick spin coating of SU-8 process is generally used in the conventional photolithography, however, additional processes such as pre- and post-baking processes and expansive precise photomasks are inevitably required. In this work, direct fabrication of HAR patterns with a high spatial resolution is tried employing two-photon polymerization in the NSL process. The precision and aspect ratio of patterns can be controlled using process parameters of laser power, exposure time, and numerical aperture of objective lens. It is also feasible to control the aspect ratio of patterns by truncation amounts of patterns, and a layer-by-layer piling up technique is attempted to achieve HAR patterns. Through the fabrication of several patterns using the NSL process, the possibility of effective patterning technique fer various N/MEMS applications has been demonstrated.

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.05a
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• pp.16.2-16.2
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• 2006

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1452-1457
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• 2011

Strength properties of cement mortar was carried out silica fume(SF) and Titanium Dioxide($TIO_2$) by nano admixture of dry process and wet process. Experimental parameters were Nano admixture as the dry process and wet process 5, 10, 15 or 20%. As a result, strength properties of cement mortar by silica fume(SF) and Titanium Dioxide($TIO_2$) were similar and in a comparative experiment of the dry process and wet process Nano admixture using wet process Nano admixture showed a greater strength properties.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.153-159
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• 2004

In this study, a new process to pattern directly on a thin metal layer using improved nano replication printing (nRP) process is suggested to evaluate the possibilities of fabricating a stamp for nano-imprinting. In the nRP process, any figure can be replicated from a bitmap figure file in the range of several micrometers with nano-scaled details. In the process, liquid-state resins are polymerized by two-photon absorption which is induced by femto-second laser. A thin gold layer was sputtered on a glass plate and then, designed patterns or figures were developed on the gold layer by newly developed top-down building approach. Generally, stamps fur nano-imprinting have been fabricated by using the costly electron-beam lithography process combined with a reactive ion-etching process. Through this study, the effectiveness of the improved nRP process is evaluated to make a stamp with the resolution of around 200nm with reduced cost.