• Progress in Superconductivity and Cryogenics
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• v.2 no.2
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• pp.11-14
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• 2000

We fabricated a resistive superconducting fault current limiter (SFCL) of meander type based on a YBCO film. In order to disperse the heat generated at hot spots in the YBCO film the film was coated with a gold shunt layer. When diodes were inserted in the parallel circuit to restrict the temperature increase in the SFCL element by reducing power supply cycles, the voltage could be increased to $\sqrt{2}$ times with the same quench resistance at a half and full cycles.

• Progress in Superconductivity
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• v.9 no.2
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• pp.188-192
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• 2008

We investigated the size effect on quench development in $Au/YBa_2Cu_3O_7$ (YBCO) thin film meander lines on sapphire substrates. The meander lines were fabricated by patterning YBCO films coated with gold layers. The lines were subjected to simulated AC fault current, and immersed in liquid nitrogen during the experiment. After the initial rapid rise, the resistance increased moderately and then slowly. In 4 inch-diameter meander lines, the period during which the resistance increased moderately was considerably longer than in 2 inch-diameter line. Moderate increase of resistance was originated from quench propagation. The film temperature was about 180 K at the point when the propagation was completed. The rate of resistance increase after the quench completion was not affected by the film size.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.85-88
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• 1999

We fabricated resistive superconducting fault current lmiters based on YBa$_2$Cu$_3$O$_{7}$ thin films and investigated their quench propagation characteristics. The YBa$_2$Cu$_3$O$_{7}$ film was coated with a gold layer and patterned into 1 mm wide meander lines by photolithography. The limiters were tested with simulated fault currents of various fault angles and amplitudes. The quench propagation characteristics were explained based on the heat transfer within the film as well as between the film and the surrounding liquid nitrogen. The quench completion time strongly depended on the potential fault current. It was 1 msec at the peak fault current of 76 A/peak/ and corresponding quench propagation speed was 43 m/sec (film cross section: 4 x 10$^{-6}$ $\textrm{cm}^2$).

• Macromolecular Research
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• v.14 no.2
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• pp.205-208
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• 2006

A polymeric film of a biodegradable poly(1,5-dioxepan-2-one) (PDXO) was formed on a gold surface by a combination of the formation of self-assembled monolayers (SAMs) presenting hydroxyl groups and the surface-initiated, ring-opening polymerization (SI-ROP) of 1,5-dioxepan-2-one (DXO). The SI-ROP of DXO was achieved by heating a mixture of $Sn(Oct)_2$, DXO, and the SAM-coated substrate in anhydrous toluene at $55^{\circ}C$. The resulting PDXO film was quite uniform. The PDXO film was characterized by polarized infrared external reflectance spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, atomic force microscopy, ellipsometry, and contact angle goniometry.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.925-927
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• 2000

We fabricated a resistive superconducting fault current limiter of meander type based on a YBCO film. In order to disperse the heat generated at hot spots in the YBCO film the film was coated with a gold shunt layer. When diodes were inserted in the parallel circuit to restrict the temperature increase in the SFCL element by reducing power supply cycles, the voltage could be increased to $\sqrt{2}$ times with the same quench resistance at a half and full cycles.

• Journal of Adhesion and Interface
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• v.11 no.4
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• pp.144-148
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• 2010

It reports the surface modification of gold nanoparticles (AuNPs) by the synthesis of thin silica layer and the fabrication of AuNPs monolayer on the glass surface. AuNPs of 10 nm in diameter were prepared in aqueous solution. A silica layer was synthesized at the different concentration of tetraethlyorthosilicate for the control of silica layer thickness. Langmuir-Blodgett (LB) film was fabricated by dispersing AuNPs on the aqueous solution and raising a surface pressure up to a solid phase. The change of AuNPs' size was observed by the change of UV/Visible spectra. Atomic force microscopic images confirmed the reliable fabrication of AuNPs LB films.

• Journal of the Korean institute of surface engineering
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• v.31 no.3
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• pp.133-141
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• 1998

Stainless is widely used for various purposes due to its good corrosion resistance. There has been much research to produce the color stainless steel by several methods. In this experiment, TixN films have been deposited on the SUS304 substrate by the DC magnetron sputtering system and the color and texture of the films as a function of coating conditions has been studies. The TixN films showed a (111) preferred orintation in bias-free conditions. The texture of coated later was changed from (111) to (200) to (2200 with a change of the bias from -1000V to -3000V. When the bias is low, coated elements have low energy. Therefore, the texturct (111) of low surface energy. The mobility of atoms was increased with the increase of the blas and texture was changed to the other plane. Non-etched specimens all exhibited strong (111) texture. This result shows that (111) is a loose plane and of non-etched specimens all exhibited. High growing velocity of (111) of especially was main texture of Non-etched specimens. Low working pressure($4\times10^{-3}$torr) was more effective than figh working pressure ($6\times10^{-3}$torr) for the gold color of $Ti_xN$ film. L and b were increased and a was decreased with the increase of bias voltage. Accordingly, We obtained the near gold color of $Ti_xN$ film(L;92, a;1~1.5 b:24~29.50. As a result of reflectance. And as the bias increased, the reflectance was proportional to the increasing bias voltage, but we took the top reflectance when the bias voltage was -200V.

• Resources Recycling
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• v.25 no.1
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• pp.3-9
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• 2016

The leaching behavior of gold from waste CPU chip using Iodide/Iodine solution was studied. The direct leaching of gold with Iodide/Iodine solution for CPU chip under the size of 150 mesh showed leaching ratio of 20%. It was assumed that the copper film was produced on the gold particle during grinding process and the copper film prevents lodine/Iodide solution from contacting with leachable gold. Meanwhile, the extraction of gold was improved to 90% by pretreatment process with $HNO_3$ solution. In order to explain the result, EDS and ICP analysis for the leaching residue were conducted. It was found that the copper coated on the surface of the gold particle was removed about 80% by $HNO_3$, resulting in the increment of gold leaching rate.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1128-1134
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• 2012

We investigated a new method for patterning organic field-effect transistors (OFETs) using a photopatternable conducting polymer nanocomposite, consisting of poly(3-hexylthiophene) (P3HT)-coated gold nanoparticles (AuNPs) that had been modified with a photoreactive cinnamate group, to form P3HT-AuNP-CI. We found that the addition of the cinnamate group to the nanoparticle surface assisted the preparation of a solvent-resistive semiconducting film and preserved the P3HT ordering, which was interrupted by Au-P3HT interactions, as well as provided UV-controllable electrical properties. The P3HT-AuNPs-CI films could be microscale-patterned via a UV crosslinking photoreaction, represented as a promising photopatternable semiconductor material for use in advanced applications, with tunable electrical properties for fabrication of sub-micron and microscale electronic devices.

• Journal of the Korean Ceramic Society
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• v.30 no.9
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• pp.695-700
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• 1993

In this study, we prepared Pb-Ti stock solution by sol-gel processing and deposited PbTiO3 thin film on a Pt coated SiO2/Si wafer by spin coating using the stock solution. We used lead acetate trihydrate and titanium isopropoxide. The stock solution was partially hydrolized and finally a 0.25M coating solution was prepared. We achieved spin coating at 4000rpm for 30 seconds and heated the thin film at 375$^{\circ}C$ for 5 minutes and at $600^{\circ}C$ for 5 minutes successively, first and second heating state. And the thin film was finally sintered at 90$0^{\circ}C$ for 1 hour in the air. The upper electrode of the thin film was made by gold sputtering and was cricle shape with radius 0.4mm. Measured dielectric constant, dissipation factor and phase transition temperature(Cuire Temp.) were about 275, 0.02 and 521$^{\circ}C$ respectively. To observe ferroelectric characteristics we calculated Pr(remnant polarization) and Ec(coercive field) byhysteresis curve. Ec was 72kV/cm and Pr was 11.46$\mu$C/$\textrm{cm}^2$.