• Macromolecular Research
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• v.17 no.9
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• pp.703-708
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• 2009

Silk fibroin scaffolds were examined as a biomaterial option for tissue-engineered cartilage-like tissue. In tissue engineering for cartilage repair using a scaffold, initial chondrocyte-material interactions are important for the following cell behaviors. In this study, the surface of nanofibrous silk fibroin (NSF) meshes was modified by a microwave-induced argon plasma treatment in order to improve the cytocompatibility of the meshes used as cartilaginous grafts. In addition, the effects of a plasma treatment on the cellular behavior of chondrocytes on NSF were examined. The plasma treatment resulted in an increase in the hydrophilicity of NSF meshes suggesting that the cytocompatibility of the mesh might be improved. Furthermore, the human articular chondrocytes showed higher viability on the surface-modified NSF meshes. These results suggest that the surface modification of NSF meshes by plasma can enhance the cellular behavior of chondrocytes and may be used in tissue engineering.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.199-207
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• 2023

Since seeds can be directly used as food resources as well as for crop cultivation or preservation of genetic resources, it is essential to develop high-quality seed processing technology to increase agricultural productivity. Seed treatment means processing technologies of seeds through physical or chemical treatment processes from after harvesting seeds to before sowing of seeds to improve germination and growth rate, durability, and immunity, etc. Since chemical seed treatment technology using pesticides or plant growth regulators has problems of environmental pollution and human toxicity, it is desired to develop an alternative technology. As a physical seed treatment method, various technologies such as ionizing radiation, plasma, microwave, and magnetic field are being developed, and some of them are being used practically. In this paper, I will summarize the mechanism of seed priming and disinfection, and the advantages and disadvantages of application, focusing on these physical seed treatment methods. Low dose or moderate intensity ionizing radiation, microwave, low-temperature plasma, and magnetic field treatments often promoted seed germination and seedling growth. However, effective removal of direct seed pathogens at these treatment intensities appears to be difficult. And it has been shown that relatively high-dose electron beam treatment using low-energy electron beams kills microorganisms on the seed surface and hull layer while not damaging the inner tissue of the seed, and is also effectively used for seed treatment on a commercial scale. In order to put the physical seed treatment technology to practical use in Korea, it is necessary to develop an economical scale treatment device along with the development of individual treatment technology to each crop.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.188-192
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• 2004

The main aim of this study was to investigate the sterilization effects of microwave-induced argon plasma at atmospheric pressure on paper materials contaminated with fungi. Plasma-treated filter papers showed no evidence to an unaided eye of burning or paper discoloration due to the plasma treatment. All fungi were perfectly sterilized in less than 1 sec, regardless of strains. These results indicate that this sterilization method for paper materials is easy to use, requires significantly less time than other traditional methods and different plasma sterilization methods, and is also nontoxic.

• Applied Science and Convergence Technology
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• v.26 no.4
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• pp.62-65
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• 2017

Passivation of surface defects by the formation of chemically inert structure at the surface of $TiO_2$ nanocrystals can be potentially useful in enhancing their photocatalytic activity. In this regard, we have studied the surface chemical states of $TiO_2$ surfaces prepared by a treatment in the afterglow of $N_2$ microwave plasma using X-ray photoemission spectroscopy (XPS). We find that nitrogen is incorporated into the surface after the treatment up to a few atomic percent. Interestingly, the surface oxynitride layer is found to be chemically stable when it's in contact with water at room temperature (RT). The surface nitrogen species were also found to be thermally stable upon annealing up to $150^{\circ}C$ in the atmospheric pressure. Thus, we conclude that the treatment of oxide materials such as $TiO_2$ in the afterglow of $N_2$ plasma can be effective way to passivate the surface with nitrogen species.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.414-415
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• 2018

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.337-350
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• 1999

Thick diamond film having ~700${\mu}{\textrm}{m}$ thickness was deposited on polycrystalline molybdenum (Mo) substrate using high power (4kW) microwave plasma enhanced chemical vapor deposition (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconductivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.441-445
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• 1999

Thick diamond film having $~700\mu\textrm{m}$ thickness was deposited on polycrystalline molybdenum(Mo) substrate using high power (4 kW) microwave plasma-enhanced chemical vapor depostion (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconcuctivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1534-1535
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• 2005

Highly luminescent efficiency phosphors have been successfully produced by surface modification and microwave irradiation treatment. The SEM image and XRD analysis reveal that the surface morphology of the white-light phosphors can be notably modified by microwave irradiation and exhibit with better crystalline property. The VUV PL spectra show that the microwave irradiation treatment can effectively enhance the luminescent efficiency by a factor of 1.5 times for intensity compared to that without microwave treatment. A further improvement in all visible emission can be made by modifying surface composition through MgO coating on the phosphor powder. These results demonstrate that such a simple approach can provide for improving luminescent efficiency of phosphors for the optoelectronic devices.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.2007-2013
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• 2017

In order to give hydrophobic surface properties on carbon steel, the fluorinated amorphous carbon films were prepared by using linear 2.45GHz microwave PECVD device. Two different process approaches have been tested. One is direct deposition of a-C:H:F films using admixture of $Ar/CH_4/CF_4$ working gases and the other is surface treatment using $CF_4$ plasma after deposition of a-C:H film with $Ar/CH_4$ binary gas system. $Ar/CF_4$ plasma treated surface with high $CF_4$ gas ratio shows best hydrophobicity and durability of hydrophobicity. Nanometer scale surface roughness seems one of the most important factors for hydrophobicity within our experimental conditions. The properties of a-C:H:F films and $CF_4$ plasma treated a-C:H films were investigated in terms of surface roughness, hardness, microstructure, chemical bonding, atomic bonding structure between carbon and fluorine, adhesion and water contact angle by using atomic force microscopy (AFM), nano-indentation, Raman analysis and X-ray photoelectron spectroscopy (XPS).

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1195-1199
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• 2011

Inactivation of foodborne pathogenic bacteria in corn silk tea was evaluated using a microwave plasma sterilization system (MPSS). Corn silk tea was inoculated with Escherichia coli and Listeria monocytogenes, treated with an MPSS treatment, and stored at 25$^{\circ}C$ for 12 days. The one, two, and three cycles of treatment with MPSS reduced the population of E. coli by 1.14, 2.49, and 5.72 log CFU/mL, respectively, compared to that of the control. In the case of L. monocytogenes, one, two, and three cycles of MPSS treatment reduced the population by 1.93, 4.49, and 6.62 log CFU/mL, respectively. Both E. coli and L. monocytogenes were eliminated within four cycles of treatment with MPSS, and even after 12 days of storage, the bacteria were not detected. Total polyphenol content in the corn silk tea did not change much among treatments, and turbidity of the corn silk tea improved following four cycles of MPSS treatment. These results suggest that MPSS treatment can be useful for improving the microbial safety and quality of corn silk tea during storage.