• Journal of the Korean Vacuum Society
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• v.20 no.5
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• pp.356-360
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• 2011

Indium oxide ($In_2O_3$) single layer and $In_2O_3$/copper (Cu) bi-layer films were prepared on glass substrates by RF and DC magnetron sputtering without intentional substrate heating. In order to determine the effect of the Cu bottom layer on the optical, electrical and structural properties of $In_2O_3$ films, 3-nm-thick Cu film was deposited on the glass substrate prior to deposition of the $In_2O_3$ films. As-deposited $In_2O_3$ films had an optical transmittance of 79% in the visible wavelength region and a sheet resistance of 2,300 ${\Omega}/{\square}$, while the $In_2O_3$/Cu film had optical and electrical properties that were influenced by the Cu bottom layer. $In_2O_3$/Cu films had a lower sheet resistance of 110 ${\Omega}/{\square}$ and an optical transmittance of 71%. Based on the figure of merit, it can be concluded that the Cu bottom layer effectively increases the performance of $In_2O_3$ films for use as transparent conducting oxides in flexible display applications.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.1-15
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• 1998

Purpose : The study for changes in components and acitvities of Artemisiae Herba at various processing temperature is generally regarded as a foundation in setting the optimum heat-processing temperature and for getting the maximum activities for medical usage of this herb. Methods: Therefore some experiments were performed either in vitro or in vivo and various changes were observed - the changes in the weitht of Artemisiae Herba, the changes in the relative amount of three kinds of extracts from Artemisiae Herba ( diluted ethanol extract, water extract, ether extract ), the TLC pattern of essential oil at various processing temperature, the existance of inhibitory effects both on ${\beta}$-Glucuronidase activities, and on heat-induced hemolysis, the effects on increased vascular permeability. The valid results derived from the experiments are as follows. Results: 1. The weight of Artemisiae Herba prominently decreased at 240^{\circ}C$. 2. The contents of diluted ether extract were maximum in the unprocessing condition. Those of water extract were maximum at 180^{\circ}C$ and at 210^{\circ}C$. and the changes of diluted ethanol extract at 150^{\circ}C$. 3. The TLC pattern of essential oil in Artemisiae Herba at various processing temperature showed that a component began to increase at Rf 0.56 and another component began to decrease at Rf 0.86. 4. The contents of Eupatilin in Artemisiae Herba at various processing temperature continued to decreased in proportion to the temperature rise, the extent of which was prominent at 210^{\circ}C$, and was unnoticeable at 270^{\circ}C$. 5. Inhibitory effects on ${\beta}$-Glucuronidase activities, trypsin activities and heat-induced hemolysis increased in proportion to the density of Artemisiae Herba. Inhibitory effects on ${\beta}$-Glucuronidase activities and trypsin activities were relatively high at 180^{\circ}C$ while on the writhing syndrome and inhibitory effects on increased vascular permeability induced by acetic acid were maximum at 240^{\circ}C$. those on heat-induced hemolysis were relatively high at 240^{\circ}C$. 6. In vivo, both analgesic effects Conclusions: To maximize of the effectiveness of Artemmisiae Herba, the ideal heating temperature is in the range of 180^{\circ}C{\sim}240^{\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.383-388
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• 2019

High purity SiC fine powder with metal impurity contents of less than 1 ppm was synthesized by improved carbothermal reduction process, and the synthesized powder was used for SiC single crystal growth in RF heating PVT device at temperature above 2,100℃. In-situ x-ray image analyzer was used to observe the sublimation of the powder and single crystal growth behavior during the growth process. SiC powder was used as a source of single crystal growth, exhausted from the outside of the graphite crucible at the growth temperature and left graphite residues. During the growth, the flow of raw materials was concentrated in the middle and influenced the growth behavior of SiC single crystals. This is due to the difference in temperature distribution inside the crucible due to the fine powder. After the single crystal growth was completed, the single crystal ingot was cut into a 1 mm thick single crystal substrate and finely polished using a diamond abrasive slurry. A dark yellow 4H-SiC was observed overall of single crystal substrate, and the polycrystals generated in the outer part may be caused by the incorporation of impurities such as the bubble layer mixed in the process of attaching the seed crystal to the seed holder.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.3
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• pp.121-125
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• 2015

GZO single layer, Ni buffered GZO(GZO/Ni), Ni intermediated GZO (GZO/Ni/GZO) and Ni capped GZO (Ni/GZO) films were prepared on poly-carbonate (PC) substrates by RF and DC magnetron sputtering without intentional substrate heating and then the influence of the Ni (2 nm thick) thin film on the optical, electrical and structural properties of GZO films were investigated. As deposited GZO single layer films show the optical transmittance of 81.3% in the visible wavelength region and a resistivity of $1.0{\times}10^{-2}{\Omega}cm$, while GZO/Ni/GZO trilayer films show a lower resistivity of $6.4{\times}10^{-4}{\Omega}cm$ and an optical transmittance of 74.5% in this study. Based on the figure of merit, it can be concluded that the intermediated Ni thin film effectively enhances the opto-electrical performance of GZO films for use as transparent conducting oxides in flexible display applications.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.198-200
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• 2014

100 nm thick Ga doped ZnO (GZO) thin films were deposited with RF magnetron sputtering on polyethylene terephthalate (PET) and ZnO coated PET substrate and then the effect of the ZnO thickness on the optical and electrical properties of the GZO films was investigated. GZO single layer films had an optical transmittance of 83.7% in the visible wavelength region and a sheet resistance of $2.41{\Omega}/{\square}$, while the optical and electrical properties of the GZO/ZnO bi-layered films were influenced by the thickness of the ZnO buffer layer. GZO films with a 20 nm thick ZnO buffer layer showed a lower sheet resistance of $1.45{\Omega}/{\square}$ and an optical transmittance of 85.9%. As the thickness of ZnO buffer layer in GZO/ZnO bi-layered films increased, both the conductivity and optical transmittance in the visible wavelength region were increased. Based on the figure of merit (FOM), it can be concluded that the ZnO buffer layer effectively increases the optical and electrical performance of GZO films as a transparent and conducting electrode without intentional substrate heating or a post deposition annealing process.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.321-323
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• 2013

100 nm thick Ga doped ZnO (GZO) thin films were deposited with DC and RF magnetron sputtering at room temperature on glass substrate and Al coated glass substrate, respectively. and the effect of the Al underlayer on the optical and electrical properties of the GZO films was investigated. As-deposited GZO single layer films had an optical transmittance of 80% in the visible wavelength region, and sheet resistance of 1,516 ${\Omega}/{\Box}$, while the optical and electrical properties of GZO/Al bi-layered films were influenced by the thickness of the Al buffer layer. GZO films with 2 nm thick Al film show a lower sheet resistance of 990 ${\Omega}/{\Box}$, and an optical transmittance of 78%. Based on the figure of merit (FOM), it can be concluded that the thin Al buffer layer effectively increases the performance of GZO films as a transparent and conducting electrode without intentional substrate heating or a post deposition annealing process.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.1
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• pp.29-33
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• 2010

Titanium nitride (TiN) films were deposited on the polycarbonate substrate by using radio frequency (RF) magnetron sputtering without intentional substrate heating. After deposition, the films were bombarded with intense electron beam for 20 minutes. The intense electron irradiation impacts on the crystalline, hardness and surface roughness of the TiN films. The films irradiated with an electron beam of 300 eV show the small grains on the surface, while as deposited TiN films did not showany grains on the surface. Also the surface harness evaluated with micro indenter was increased up to 18 Gpa at electron energy of 900 eV after electron beam irradiation. In addition, surface root mean square (RMS) roughness of the films irradiated with intense electron beam affected strongly. The films irradiated by electron beam with 900 eV have the lowest roughness of 1.2 nm in this study.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.474-477
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• 2002

Equipment to cauterize tumors by an electrically heated Kanthal wire is under development. The wire( alloy of iron, chromium and Aluminum) keeps sufficient strength up to 1400 degrees in Celsius. Although AC 50Hz current source is used in the prototype experiment, RF current will be used in future. The diameter of the Kanthal wire was 0.3 mm which was connected to Kanthal wire of 0.8 mm. The thicker wire was used as a leading wire. The possibility of application of the heating wire in combination with an ultrasound endoscope was determined, where ultrasound endoscope is to be used to monitor the location on the wire and an extent of a tumor in digestive organs. This procedure requires the wire to be applied inside ultrasound transmitting media. First, the wire was applied in the degassed water in which a chicken liver sample was submerged. The wire, however, burned out in water soon after it became red-hot at 12 A. The reason is that large current is required for the wire to become red-hot due to strong convection. Starch paste of 3 weight percent was employed instead of water. This made the wire red-hot approximately at 6 A, showing the increased viscosity of the starch decreased the convection and the wire was cover by the steam. The liver sample was cauterized successively, while the location of the wire and the liver was monitored by an ultrasound diagnosis equipment outside the plastic vessel of the starch paste.

• Korean Journal of Materials Research
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• v.20 no.12
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• pp.636-639
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• 2010

ZnO thin films were prepared on a glass substrate by radio frequency (RF) magnetron sputtering without intentional substrate heating and then surfaces of the ZnO films were irradiated with intense electrons in vacuum condition to investigate the effect of electron bombardment on crystallization, surface roughness, morphology and hydrogen gas sensitivity. In XRD pattern, as deposited ZnO films show a higher ZnO (002) peak intensity. However, the peak intensity for ZnO (002) is decreased with increase of electron bombarding energy. Atomic force microscope images show that surface morphology is also dependent on electron bombarding energy. The surface roughness increases due to intense electron bombardment as high as 2.7 nm. The observed optical transmittance means that the films irradiated with intense electron beams at 900 eV show lower transmittance than the others due to their rough surfaces. In addition, ZnO films irradiated by the electron beam at 900 eV show higher hydrogen gas sensitivity than the films that were electron beam irradiated at 450 eV. From XRD pattern and atomic force microscope observations, it is supposed that intense electron bombardment promotes a rough surface due to the intense bombardments and increased gas sensitivity of ZnO films for hydrogen gas. These results suggest that ZnO films irradiated with intense electron beams are promising for practical high performance hydrogen gas sensors.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.267-270
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• 2010

Sn doped $In_2O_3$ (ITO) and ITO/Cu/ITO (ICI) multilayer films were prepared on glass substrates with a reactive radio frequency (RF) magnetron sputter without intentional substrate heating, and then the influence of the Cu interlayer on the methanol gas sensitivity of the ICI films were considered. Although both ITO and ICI film sensors had the same thickness of 100 nm, the ICI sensors had a sandwich structure of ITO 50 nm/Cu 5 nm/ITO 45 nm. The ICI films showed a ten times higher carrier density than that of the pure ITO films. However, the Cu interlayer may also have caused the decrement of carrier mobility because the interfaces between the ITO and Cu interlayer acted as a barrier to carrier movement. Although the ICI films had two times a lower mobility than that of the pure ITO films, the ICI films had a higher conductivity of $3.6{\cdot}10^{-4}\;{\Omega}cm$ due to a higher carrier density. The changes in the sensitivity of the film sensors caused by methanol gas ranging from 50 to 500 ppm were measured at room temperature. The ICI sensors showed a higher gas sensitivity than that of the ITO single layer sensors. Finally, it can be concluded that the ICI film sensors have the potential to be used as improved methanol gas sensors.