• Carbon letters
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• v.2 no.1
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• pp.27-36
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• 2001

The pack-cementation process is the method which is formed SiC coating layer to improve weak oxidation properties of CFRCs (carbon fiber-reinforced carbons). This method develops the anti-oxidation coating layer having no dimensional changes and good wetting properties. In this study to improve the oxidative resistance of the prepared 4D CFRCs, the surface of CFRCs is coated by SiC using pack cementation method. The mechanical properties of SiC-coated 4D CFRCs are measured by the 3-point bending test, and their ablation properties are investigated by the arc torch plasma test. From the results, it is found that both mechanical and ablation properties of SiC-coated 4D CFRCs are much better than bare CFRCs.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.43-46
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• 2004

Multi-walled carbon nanotubes (MWNTs) produced by chemical vapor deposition were treated with acidic solution for purification and oxidization of CNTs. The surface modification of the oxidized CNTs was achieved by amine treatment and oxygen plasma treatment. The functionalized CNTs were embedded in the epoxy resin by sonication method and the resulting composite was investigated by FESEM. Rheological and mechanical properties of nanocomposites were measured by AR2000 and Instron. The rheological properties and dispersion of modified CNTs/epoxy composites were improved as CNTs were modified, because the modification of CNTs led to a improvement interaction between the CNTs and the epoxy resin. In addition to this, mechanical properties are also improved because of the effective stress transfer between the CNTs and the polymer.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1078-1082
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• 2003

A feasibility study for the fabrication of master replication with nanostructures by Nanoimprint Lithography (NIL) was investigated for application of polymer Photonic Bandgap (PBG) devices used in photonic IC. Large area gratings of $9{\times}15(mm^2)$ with p = 400 nm was successfully embossed on PMMA on silicon wafer and the embossing parameters (temperature, pressure, time) were established. A precise control of $O_2$ plasma Reactive Ion Etching (RIE) process time allowed window opening over the whole area despite the presence of wafer bending. Master replication with aspect ratio 1 was successfully fabricated, but master replication with aspect ratio 3 needs to optimize parameters. All replications were done in a NIL process.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.177-186
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• 1994

Bioadhesive microcapsules of cephalexin, using Eudragit RS/RL coated with polycarbophil or carbopol, were evaluated biopharmaceutically. The GI transit of microcapsules in rats was studied. Bioadhesive microcapsules coated with polycarbophil or carbopol were shown to have substantially longer GI transit time than Eudragit RS/RL microcapsule. The delay in transit time was due to bioadhesion of the polymer to the mucin-epithelial cell surface which was clearly observable on animal autopsy. Plasma drug levels in rabbits showed that bioadhesive microcapsules resulted in a longer duration of action and greater bioavailability than other microcapsule or drug powder. Thus, the principle of bioadhesion can significantly improve therapy, due to a reduced rate of gastric emptying, an increase in contact time, and the intimacy of contact of the drug with the absorbing membrane.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.53-56
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• 2004

Morphology of membrane affects its performance [1]. For a constant amount of fixed charges, the distribution of these charges is also significant to its performance (2). In some ionomer membranes such as Nafion, the membrane fixed charge is not randomly distributed, but occurs in clusters. Thus, the membrane solution is phase-separated, with the ion clusters, acting as inverted micelles in a polymer solvent.(omitted)

• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.313-322
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• 1995

The covalent conjugation of human recombinant superoxide dismutase (hrSOD) with trichloros-triazine activated polyethylene glycol (PEG) 5000 formed soluble conjugates with molecular weight of 92KD, which retained $90{\sim}98%$ of original activity with a markedly prolonged plasma half-life of enzyme activity. The effect of hrSOD-PEG conjugates on acetaminophen (ACP)-induced hepatotoxicity was tested in male rats which were pretreated with 3-methylcholanthrene. HrSOD-PEG conjugates inhibited the hepatotoxicity produced by ACP, on the other hand, native hrSOD had no protective effect. The above results indicated that oxygen radicals might participate in the mechanism of the ACP-induced hepatotoxicity and that polymer conjugated-protein drugs with prolonged half-lives could be employed as an effective therapeutic agent.

• Proceedings of the Korean Vacuum Society Conference
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• 2001.07a
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• pp.143-144
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• 2001

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2539-2542
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• 2013

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.524-530
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• 2013

In this study, we describe the most expected behavior of cells on the modified surface and the correlation between the modified substrates and the response of cells. The physicochemical characteristics of substrates played an essential role in the adhesion and proliferation of cells. Glass and polymer substrates were modified using air plasma oxidation, and the surfaces were coated with self-assembled monolayer molecules of silanes. The PDMS substrates embedded with parallel micropatterns were used for evaluation of the effect of topologically modified substrate on cellular behaviour. BALB/3T3 fibroblast cells were cultured on different surfaces with distinct wettability and topology, and the growth rates and morphological change of cells were analyzed. Finally, we found the optimum conditions for the adhesion and proliferation of cells on the modified surface. This study will provide insight into the cell-surface interaction and contribute to tissue engineering applications.

• Carbon letters
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• v.27
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• pp.50-63
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• 2018

An imprinted potentiometric sensor was developed for direct and selective determination of gabapentin. Sensor is based on carbon paste electrode adapted by graphene oxide that is decorated with silver nanoparticles and mixed with molecularly imprinted polymers nanoparticles using gabapentin as a template molecule. The synthesized nanoparticles were characterized by Fourier transmission infrared spectroscopy, transmission electron microscopy and X-ray diffraction. Under optimal experimental conditions, the studied sensor exhibited high selectivity and sensitivity with LOD of $4.8{\times}10^{-11}mol\;L^{-1}$. It provided a wide linearity range from $1{\times}10^{-10}$ to $1{\times}10^{-3}mol\;L^{-1}$ and high stability for more than 3 mo. The sensor was effectively used for the determination of gabapentin in pharmaceutical tablets and spiked plasma samples.