• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.04a
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• pp.29-30
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• 2001

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.8-15
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• 2024

In this study, nitrogen plasma treatment was performed in 5, 10, and 15 minutes to improve the tetracycline adsorption performance of activated carbon. All nitrogen plasma-treated activated carbons showed improved tetracycline adsorption compared to untreated activated carbons. The nitrogen functional groups in activated carbon lead to chemisorption with tetracycline via π-π interactions and hydrogen bonding. In particular, in the nitrogen plasma treatment at 80 W and 50 kHz, the activated carbon treated for 10 minutes had the best adsorption performance. At this time, the nitrogen content on the surface of the activated carbon was 2.03% and the specific surface area increased to 1,483 m²/g. As a result, nitrogen plasma treatment of activated carbon improved its physical and chemical adsorption capabilities. In addition, since the adsorption experimental results were in good agreement with the Langmuir isotherm and pseudo-second order model, it was determined that the adsorption of tetracycline on the nitrogen plasma-treated activated carbon was dominated by chemical adsorption through a monolayer. As a result, nitrogen plasma-treated activated carbon can be used as an adsorbent to efficiently remove tetracycline from water due to the synergistic effect of physical adsorption and proactive chemical adsorption.

• Journal of Powder Materials
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• v.11 no.5
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• pp.363-368
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• 2004

In the present study, the focus is on the analysis of the effect of the mold dimensions on the temperature distribution of a die during plasma activated sintering. The temperature distribution of a cylindrical mold with various dimensions was measured using K-type thermocouples. The temperature homogeneity of the die was studied based on the direction and dimensions of the die. A temperature gradient existed in the radial direction of the die during the plasma activated sintering. Also, the magnitude of the temperature gradient was increased with increasing sintering temperature. In the longitudinal direction, however, there was no temperature gradient. The temperature gradient of the die in the radial direction strongly depended on a ratio of die volume to punch area.

• Carbon letters
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• v.6 no.4
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• pp.243-247
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• 2005

Plasma polymerization of allylamine subsequently after plasma pre-treatment was conducted on the activated carbon fibers (ACFs) for the immobilization of amine groups in the surface of ACFs. The change of structural properties of ACFs with respect to different polymerization conditions was investigated through BET method. The change of surface morphologies of ACFs with respect to different plasma polymerization power was also studied through AFM. It was found that the structural properties such as specific surface area and micropore volume could be optimized under certain plasma deposition conditions. It was reckoned that treatment and deposition showed adverse effect on plasma polymerization, in which the former developed the micro-structures of the ACFs and the latter tended to block the micro pores. The Fourier transform infrared spectroscopy (FTIR) revealed that the poly(allylamine) was successfully immobilized on the surface of ACFs and the amount of the deposited polymer layer was related to the plasma polymerization power. SEM results showed that the plasma deposited polymer layer were small and homogenously distributed. The size and the distribution of particles deposited were closely related to the plasma polymerization power, too.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.280-286
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• 1994

As-grown $YBa_2Cu_3O_{7-x}$ films on MgO(100)substrates were prepated by a reactive co-evaporation method, and effects of activated oxygen plasma on the crystallinity and superconductivity at substrate temperature ranging from $450^{\circ}C$ to $590^{\circ}C$ were investigated. The film deposited under the activated oxygen plasma at the substrate temperature of $590^{\circ}C$ had a single crystal phase. Whereas, when films were deposited under only oxygen gas, they were not in perfect single crystal phase but with slight polycrystalline nature. When the substrate temperature was $590^{\circ}C$, $Tc_{zero}$'s were 83K and 80K for films with and without activated oxygen plasma, respectively. The critical temperature, the crystal structure and the surface morphology of as-grown films were found to be insensitive to the activated oxygen plasma which is introduced during deposition instead of oxygen gas, but the crystalline quality was improved somewhat by the introduction by the introduction of actvated oxygen plasma.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.68-68
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• 1993

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.05a
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• pp.89-89
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• 1999

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.05a
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• pp.82-82
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• 1993

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.851-856
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• 1996

Copper Phthalocyanine (CuPc) thin films were fabricated on the silicon wafers by plasma activated evaporation method and structural analysis were carried out with various spectroscopies. The CuPc films had dense and smooth morphology and they also showed good mechanical properties and chemical resistance. The main molecular structure of the CuPc, which is the conjugated aromatic heterocyclic ring structure, was maintained even in the plasma process. However, metal-ligand (Cu-N) bands were deformed by the plasma process and the structure became amorphous especially at higher process pressures. Oxygen impurities were incorporated in the film and carboxyl functional groups were formed at the peripheral benzene ring. The structure and morphology of the films were dependent on the process pressure but relatively irrespective of the RF power.

• Carbon letters
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• v.5 no.3
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• pp.103-107
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• 2004

The atmospheric pressure plasma treatments ($Ar/O_2$ and $Ar/N_2$) of activated carbon fibers (ACFs) were carried out to introduce hydrophilic functional groups on carbon surfaces in order to enhance the hydrogen chloride gas (HCl) adsorption. Surface properties of the ACFs were determined by XPS and SEM. $N_2$/77 K adsorption isotherms were investigated by BET and D-R (Dubinin-Radushkevich) plot methods. The HCl removal efficiency was confirmed by HCl detecting tubes (range:1~40 or 40~1000 ppm). As experimental results, it was found that all plasma-treated ACFs showed the decrease in the pore volume, but the HCl removal efficiency showed higher level than that of the untreated ACFs. This result indicated that the plasma treatments led to the conformation of hydrophilic functional groups on the carbon surfaces, resulting in the increase of the interaction between the ACFs and HCl gas.