• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.3-4
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• 2004

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.63-68
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• 2015

Micro/nano patterns for optical concentration and diffusion have been studied in the various fields such as displays, optics, and sensors. Conventional micro patterns were continuous and linear shapes due to using linear-type light sources, however, recently non-continuous patterns have been applied as point sources are used for dot-type light sources such as LEDs and OLEDs. In this study, a hybrid machining technology combining an indentation machining method and an AAO process was developed for manufacturing the non-continuous micro patterns having nano patterns. First, mirror-like surfaces ($R_a<20nm$) of pure Aluminum substrates were obtained by optimizing cutting conditions. Then, The letter of 'K' consisting of the arrays of the micro patterns was manufactured by the indentation machining method which has a similar principle to indentation hardness testing. Finally, nano patterns were machined by AAO process on the micro patterns. Conclusively, a specific letter having nano-micro hybrid patterns was manufactured in this study.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.13-16
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• 2005

Nanoscale materials are of great interest due to their unique optical, electrical and magnetic properties. Due to the recent amazing achievements in nano technology, new materials were developed. But these nano technology is not apply to the construction part in spite of exellent properties of nano size material. The purpose of this study is to apply to nano technology into building materials. To develop the high performance concrete, nano cement particles is prepared by mechanical method. In the results of this study, the nano silica powder increase effect according to increase of the mixing amount, appeared that compressive strength increased but is limit in increment. For the production of high-strength concrete, nano silica powder was suitable the binder ratio from 20$\%$. And, the compressive strength of concrete are especially dependent on the curing temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.310-311
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• 2008

We have studied electro-optical characteristics of fringe-field switching (FFS) mode with high $d{\Delta}n$ according to the electrode position. In this device, the fringe-electric field drives the LCs to rotate so that the dielectric torque is electrode-positional dependent, which results in electrode-position dependency in the LC's rotating angle. We confirmed polarization microscope image and chromaticity diagram at the different electrode position with LC that have high $d{\Delta}n$. Since the FFS mode is influenced by horizontal and vertical electric field, the FFS mode modulates light using both phase retardation and polarization rotation effect, which had already been verified with previous studies. However, from another point of view, tight modulation of FFS mode has been demonstrated by performing experiment and calculated simulation at the high $d{\Delta}n$ LC cell.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.224-226
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.217-217
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• 2005

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.130-131
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• 2005

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.337-338
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• 2008

We have studied electro-optic characteristics of a high performance liquid crystal display using Fringe In-plane field Switching (FIS) mode. The strong electric fields cause more liquid crystals to reorient almost in plane above and between the pixel electrodes. As a result, the operation voltage is lower and transmittance is higher than those of Fringe Field Switching (FFS) and In-Plane Switching (IPS) modes. Apparently, the transmittance depends on voltage applied at the configurations of FIS mode which are proposed. Therefore, we have studied certain length of between electrodes for maximum transmittance and light intensity.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.313-313
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• 2012

ZnO and $SnO_2$, well-known wide direct band-gap semiconductors, have been considered as the most promising functional materials due to their highly sensitive gas sensing and excellent optical properties. ZnO/$SnO_2$ epitaxial hetrostructure exhibited unique luminescence properties in contrast with individual tetra-pod ZnO and $SnO_2$ nanostructures. Polycrystalline $SnO_2$-based samples $Zn_xSn_{1-x}O_2$(x=0, 0.01, 0.03, 0.05) were prepared by solid state reaction and eco-friendly hydrothermal techniques. Scanning electron microscopy equipped with electron dispersive x-ray spectra confirms the formation of near stoichiometric $Zn_xSn_{1-x}O_2$ nanorods of diameter ~10 nm. X-ray diffraction analysis revealed the rutile structure, except for x=0.07, which may have a small part of $Zn_2SnO_4$ as a secondary phase.

• Korean Journal of Materials Research
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• v.18 no.5
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• pp.253-258
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• 2008

A simple method to deposit carbon nanotube films uniformly on large area substrates using an arc discharge method is reported in this paper. The arc discharge method was modified to deposit carbon nanotube films in situ on the substrates. The substrates were scanned several times over the arcing point for a uniform film thickness. Deposition was carried out under variable dc bias conditions at 600 torr of $H_2$ gas. The thickness uniformity of the single-wall carbon nanotube films as characterized by a four-point probe was within 30% deviation. The morphology and crystal quality of the single-wall carbon nanotube film were also characterized by field emission scanning electron microscopy and Raman spectroscopy.