• Journal of the Korean institute of surface engineering
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• v.42 no.3
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.249-254
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• 2015

Solution-derived amorphous indium-gallium-zinc oxide (a-IGZO) thin-film-transistor (TFTs) were developed using a microwave irradiation treatment at low process temperature below $300^{\circ}C$. Compared to conventional furnace-annealing, the a-IGZO TFTs annealed by microwave irradiation exhibited better electrical characteristics in terms of field effect mobility, SS, and on/off current ratio, although the annealing temperature of microwave irradiation is much lower than that of furnace annealing. The microwave irradiated TFTs showed a smaller $V_{th}$ shift under the positive gate bias stress (PGBS) and negative gate bias stress (NGBS) tests owing to a lower ratio of oxygen vacancies, surface absorbed oxygen molecules, and reduced interface trapping in a-IGZO. Therefore, microwave irradiation is very promising to low-temperature process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.350-356
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• 2005

We report the space charge and the surface potential of the interface between metal and copper(Ⅱ)-phthalocyanine(CuPc) thin films by measuring the microwave reflection coefficients S/sub 11/ of thin films using a near-field scanning microwave microscope(NSMM). CuPc thin films were prepared on Au and Al thin films using a thermal evaporation method. Two kinds of CuPc thin films were prepared by different substrate heating conditions; one was deposited on preheated substrate at 150。C and the other was annealed after deposition. The microwave reflection coefficients S/sub 11/ of CuPc thin films were changed by the dependence on grain alignment due to heat treatment conditions and depended on thickness of CuPc thin films. Electrical conductivity of interface between metal and organic CuPc was changed by the space charge of the interface. By comparing reflection coefficient S/sub 11/ we observed the electrical conductivity changes of CuPc thin films by the changes of surface potential and space charge at the interface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.526-530
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• 2004

We report the space charge and the surface potential of the interface between metal and CuPc according to isotropic property and different metal by measuring the microwave reflection coefficients $S_{11}$ of copper(II)-phthalocyanine(CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand. CuPc thin films were prepared on gold and aluminium substrates using a thermal evaporation method. Two kinds of CuPc thin films were prepared. One was deposited on preheated substrate at $150^{\circ}C$ and the other was annealed after deposition by using thermal evaporation methods. The microwave reflection coefficients $S_{11}$ of CuPc thin films were changed by the dependence on the heat treatment conditions. By comparing reflection coefficient $S_{11}$ we measured electrical conductivity of CuPc thin films and studied this results with respect to the surface potential and space charge of the interface between metal and CuPc thin films.

• 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 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).

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1349-1351
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• 2001

Polycrystalline diamond films are deposited by using a microwave plama CVC system, where the bias-enhanced nucleation (BEN) method is employed. Effects of the varying microwave power, the surface treatment by hydrogen plasma, and the cyclic hydrogen etching during deposition on the crystallinity as well as on the surface roughness of deposited films are examined by Raman spectroscopy, SEM, and AFM. A novel method for achieving a smoother diamond surface is also suggested through the indirect wafer bonding and back-side polishing.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2606-2613
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• 2022

Spent resin often exceeds radiation limits for safe disposal, creating a need for commercial-scale treatment techniques to reduce resin radioactivity. In this study, the radiological safety of a commercialized spent resin treatment device with a treatment capacity of 1 ton/day was evaluated. The results confirm that the device is radiologically safe in the event of an accident. This device desorbs ¹⁴C from the spent resin, allowing disposal as low-level waste instead of intermediate-level waste. The device also reduces overall waste by recycling the extracted ¹⁴C. Potential accident scenarios were explored to enable dose assessments for both internal and external exposure while preventing further spillage of the device and processing the spilled resin. The scenarios involved the development of a surface fracture on the resin mixture separator and microwave systems, which were operated under pressure and temperature of 0-6 bar and 0-150 ℃, respectively. In the case of accidents with separator and microwave device, the maximum allowable working time of worker were derived, respectively, considering external and internal exposures. When wearing the respirator corresponding to APF 50, in the case of the microwave device accident scenario, the radiological safety was confirmed when the maximum worker worked within 132.1 h.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1113-1115
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• 2002

Mesoporous silica, MCM-41, was synthesized by sol-gel method. The organic structure-directing agent must be removed to make the desired proes. To achieve this, alternative calcination method using microwave oven was adapted to this removal stage. Microwave calcination was shown to provide a novel, rapid and inexpensive method of praparing nanoporous material. It was studied how the porous structure, surface area and pore size distribution were changes under microwave calcination.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.2
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• pp.75-80
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• 2021

The crystal grains of polycrystalline diamond vary depending on deposition conditions and growth thickness. The diamond thin film deposited by the CVD method has a very rough growth surface. On average, the surface roughness of a diamond thin film deposited by CVD is in the range of 1-100 um. However, the high surface roughness of diamond is unsuitable for application in industrial applications, so the surface roughness must be lowered. As the surface roughness decreases, the scattering of incident light is reduced, the heat conduction is improved, the mechanical surface friction coefficient can be lowered, and the transmittance can also be improved. In addition, diamond-coated cutting tools have the advantage of enabling ultra-precise machining. In this study, the surface roughness of diamond was improved by thermal diffusion reaction between diamond carbon atoms and ferrous metals at high temperature for diamond thin films deposited by MPCVD.