• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.2
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• pp.184-189
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• 2002

Carbon nitride films were grown on Si (100) substrate by a laser-electric discharge method with/without a magnetic field assistance. The magnetic field leads to vapor plume plasma expending upon the ambient arc discharge plasma area. Influence of the magnetic field has resulted in increased of a crystallite size int he films due to bombardment (heating) of Si substrates by energetic carbon and nitrogen species generated during cyclotron motion of electrons in the discharge zone. The surface morphology of the films with a deposition time of 2 hours was studied using a scanning electron microscopy (SEM). In order to determine the structural crystalline parameters, X-ray diffraction (XRD) was used to analysis the grown films.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1606-1608
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• 1994

A performance of the torch greatly depends on the plasma gas and the cooling gas. The plasma gas constricted by the nozzle concentrates electric power and momentum, so it can eject molten metal from a cut. As an electric arc constricted in a nozzle is more constricted through thermal pinch by the cooling gas, it is possible to transfer larger thermal concentration to the workpiece. The optimized parameter value in this study was given below. Plasma gas pressure is $4[kgf/cm^2]$ and gas mass flow is $30[{\ell}/min]$. Cooling gas pressure is $6[kgf/cm^2]$ and gas mass flow is $120[{\ell}/min]$.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.169-174
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• 2004

MgO thin films were reactively deposited using an internal inductively coupled plasma assisted sputtering method varying reactive gas ratio to get stoichiometric film composition, and bipolar dc substrate bias to suppress micro arcs. The minimum frequency required for arc suppression was about 10KHz depending on ICP power. Their crystallinity was analyzed using X-ray diffraction and surface morphology using AFM. The surface was very smooth with rms roughness less than 0.42nm. The preferred orientation of the films were changing from (200) to bulk-like characteristics as Ar: $O_2$ratio was controlled to 10 : 2. Optical emission spectroscopy revealed that there were two distinct discharge modes: a blue one and a green one, where enhanced emission from Ar and Mg were observed. This cannot simply be understood by metallic or oxide mode of reactive sputtering due to ICP coupled to magnetron discharge.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.4
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• pp.770-783
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• 2015

Lately, high production rate welding processes for Al alloys, which are used as LNG FPSO cargo containment system material, have been developed to overcome the limit of installation and high rework rates. In particular, plasma-metal inert gas (MIG) hybrid (PMH) welding can be used to obtain a higher deposition rate and lower porosity, while facilitating a cleaning effect by preheating and post heating the wire and the base metal. However, an asymmetric undercut and a black-colored deposit are created on the surface of PMH weld in Al alloys. For controlling the surface defect formation, the wire feeding speed and nozzle diameter in the PMH weld was investigated through arc phenomena with high-speed imaging and metallurgical analysis.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.429-434
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• 2001

Ti-Cu-N nanocomposite films deposited by arc ion plating and magnetron sputter hybrid system with various copper contents. The microstructure and mechanical properties of Ti-Cu-N superhard nanocomposite films depend on the Cu concentration. In X-ray diffraction (XRD) analysis, intensity of TiN (111) and TiN (220) peak decreased and peak broadness increased with increasing the copper contents and Cu peak was not detected. The grain size of films decreased with increasing at%Cu and Transmission Electron Microscopy (TEM) analysis also showed that Ti-Cu-N film containing 1.5at%Cu was composed of very fine (<10nm) nanocrystalline grains. The maximum hardness of Ti-Cu-N (1.5at%Cu) film reached to 45GPa and friction coefficient was measured 0.3.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.421-430
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• 2004

The purpose of this study was to measure and compare the amount of unreacted TEGDMA from pit and fissure sealants cured with three different light sources; conventional halogen light curing unit, plasma arc light curing unit and argon laser. The specimens were eluted in distilled water for different time intervals. The time-related release of TEGDMA were analyzed by reverse-phase high performance liquid chromatography(HPLC). The result of present study can be summarized as follows: 1. The time-related release of TEGDMA decreased with increasing curing time in conventional halogen light, however, that not statistically significant difference(p>0.05). 2. The elution from the specimens cured for 6 and 9 seconds with plasma arc light was similar results corresponding with the time-related TEGBMA release, and was significantly lower than that cured for 3 seconds(p<0.05). 3. The elution of TEGDMA from the specimens cured with argon laser was significantly higher than that cured with halogen and plasma arc light(p<0.05). 4. The elution of TEGDMA from under recommended time of three different light sources were showed to be no statistically significant difference(p>0.05). 5. In time-related release of TEGDMA from recommended time of each light sources, the results correspond to 40 seconds of halogen light and 6 seconds of plasma arc light were similar(p>0.05). 6. The elution of TEGDMA, from over recommended time of three different light sources were showed to be no statistically significant difference(p>0.05). In this study, I suggest that curing time of plasma arc light is 6 and/or 9 seconds in the field of clinical pediatric dentistry claiming its effectiveness in optimal polymerization and reduced chair time.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.240-240
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• 2011

The first neutral beam injector (NBI-1) has been developed for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. A first long pulse ion source (LPIS-1) has been installed on the NBI-1 for an auxiliary heating and current drive of KSTAR core plasmas. Performance of ion and neutral beam extractions in the LPIS-1 was investigated initially on the KSTAR NBI-1 system, prior to the neutral beam injection into the main plasmas. The ion source consists of a JAEA magnetic bucket plasma generator with multi-pole cusp fields and a set of KAERI prototype-III tetrode accelerators with circular apertures. The inner volume of plasma generator and accelerator column in the LPIS-1 is approximately 123 liters. Final design requirements for the ion source were a 120 kV/ 65 A deuterium beam and a 300 s pulse length. The extraction of ion beams was initiated by the formation of arc plasmas in the LPIS-1, called as an arc-beam extraction method. A stable ion beam extraction of LPIS-1 has been achieved up to an 100 kV/42 A for a 4 s pulse length and an 80 kV/25 A for a 14 s pulse length. Optimum beam perveance of 1.21 microperv has been found at an accelerating voltage of 80 kV. Neutralization efficiency has been measured by using a water flow calorimetry (WFC) method of calorimeter and an operation of bending magnet. The full-energy species of ion beams have been detected by using the diagnostic method of optical multichannel analyzer (OMA). An arc efficiency of the LPIS was 0.6~1.1 A/kW depending on the operating conditions of arc discharge.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.357-364
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• 2018

Fly ash is a material used as a concrete admixture. When fly ash is used for concrete manufacturing, it is expected to improve the performance such as reduction of cement usage and increase of chemical resistance. However, fly ash have some problems such as unburned carbon content and amorphous film on the surface of fly ash particles. When concrete is manufactured using fly ash containing a large amount of unburned carbon, there is a problem that the slump is lowered due to adsorption of AE agent. In addition, the amorphous film on the surface of the particles prevents the reactive substances from leaching out of the fly ash. Therefore, a method of surface treatment of fly ash using plasma has been studied to remove such unburned carbon and amorphous films. However, plasma has the problem that $O_3$ is generated when $O_2$ is used as an active gas. $O_3$ is a harmful substance and adversely affects the health of the experimenter. In this study, the surface of fly ash was treatment by arc discharge. Experimental results show that the unburned carbon is removed when the surface of fly ash is treatment by arc discharge and the amorphous film was broken and the reactivity was improved. Therefore, it is considered that arc discharge can treatment the surface of fly ash and improve the quality of fly ash.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.96-101
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• 2008

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by Ion-Beam-Assisted Deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, Oxygen-Neutral-Beam-Assisted Deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen neutral beam energy of 300eV. The surface morphology of MgO thin film was also analyzed using AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy).

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.199-206
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• 2001

The purpose of study was to compare the plasma arc light with the halogen light in compostie resin curing. Three composite resin materials(Z-100, 3M, USA; Tetric Ceram, Vivadent, Liechtenstein; SureFil, Dentsply, USA) were filled in the teflon molds (4mm in diameter and 2, 3, 4, 5mm in thickness) and cured with either the conventional low-intensity light curing unit with a halogen lamp (Optilux 360, Demetron, U.S.A.) for duration of 40 seconds or with the high-intensity light curing unit with a plasma arc lamp (Flipo, Lokki, France) for duration of 3, 6, and 9 seconds. The intensity of halogen light was about $370mW/cm^2$ and that of plasma light was about $1,900mW/cm^2$. After one week, the surface hardnesses of both the top and the bottom of the resin samples were measured with a microhardness tester(MXT70, Matsuzawa, Japan). There were significant differences in the hardness between the top and the bottom of the resin samples except the 2mm thickness samples cured by halogen light for 40s or by plasma light for 9s. There was no significant difference between the hardness values of the top surfaces of the thickness groups. The hardness values of the bottom surfaces decreased as the curing time decreased and as the thickness of resin samples increased, and the three kinds of resin composites showed similar patterns. The results suggest that the halogen light for 40 seconds might be able to cure greater depth of resin composites than the plasma light for 3, 6, or 9 seconds.