• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.165-165
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• 2014

In this study, we demonstrated that the soft lithographic patterning processing of chemical vapor deposition (CVD) graphene and rGO sheets as large scale, low cost, high quality and simplicity for future industrial applications. Recently, a previous study has reported that single layer graphene grown via CVD was patterned and transferred to a target surface by controlling the surface energy of the polydimethylsiloxane (PDMS) stamp [1]. Using this approach, the surface of a relief-patterned elastomeric stamp was functionalized with hydrophilic dimethylsulfoxide (DMSO) molecules to enhance the surface energy of the stamp and to remove the graphene-based layer from the initial substrate and transfer it to a target surface [2]. Further, we developed a soft lithographic patterning process via surface energy modification for advanced graphene-based flexible devices such as transistors or simple and efficient chemical sensor consisting of reduced graphene oxide (rGO) and a metallic nanoparticle composite. A flexible graphene-based device on a biocompatible silk fibroin substrate, which is attachable to an arbitrary target surface, was also successfully fabricated.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.80-85
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• 2017

Recently, microalgae which can produce high-value products have attracted increasing attention for biological conversion of $CO_2$. However, low photosynthetic efficiency and productivity have limited the practical use of microalgae. Thus, we developed microdroplet photobioreactor for the analysis of photoautotrophic growth of model alga, Chlamydomonas reinhardtii. $CO_2$ transfer rate was increased by integrating micropillar arrays and adjusting height of microchamber. These results were identified by change of cell growth rate and fluorescence intensity. Lastly, the photoautotrophic growth kinetics of C. reinhardtii in microdroplet photobioreactor were investigated under different $CO_2$ concentrations and light intensities for 96 hours. As a result, microdroplet photobioreactor was efficient platform for isolation and rapid evaluation of microalgal strains which have enhanced productivity of high-value products and growth performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.7-14
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• 2010

This paper describes the effects of kinetic parameters such as attaching speed, attaching time, and dettaching speed on printing property of electrodes which were fabricated by micro-contact printing with Ag ink. In inking process the attaching speed was preferable to be less than 1 mm/s, attaching time as short as possible, and detaching speed larger than 1000 mm/s in order to obtain the transfer ratio of ink larger than 98%. Meanwhile in printing process the parameters were totally opposite to the results of inking process; attaching speed larger than 100 mm/s, attaching time larger than 30 sec, and detaching speed less than 1 mm/s for the best results. With the parameters we could obtain the micro-contact printed electrodes with the minimum line width of $30\;{\mu}m$, thickness of 300~500 nm, roughness less than 50 nm, and resistivity of about $15{\sim}16{\mu\Omega\cdot}cm$.