• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1197-1201
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• 2003

Thin film on SiO$_2$ glass was synthesized by a dip-coating method from the ZrO$_2$ sol which had dispersed nanosize Au particle under ambient atmosphere. After heat treatment of the prepared thin film, the characteristics were investigated by X-ray diffraction, UV-VIS spectrometer, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). It was found that ZrO$_2$ thin film with 100 nm thickness was crystallized to tetragonal phase at 50$0^{\circ}C$. The size of dispersed Au particle was 15∼40nm and the film had a smooth surface with a roughness of 0.84 nm. The film showed nonlinearity characteristics with absorption peaks at 630∼670nm visible region because of the plasma resonance of Au metallic particles.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.147-151
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• 2007

Cu-free multi-component sol, of which final oxide composition becomes $Bi_{1.9}Pb{0.35}SrCaO,\;Bi_{1.8}Pb_{0.2}SrCaO\;and\;Bi_{1.5}SrCaO$, respectively, was prepared through sol-gel route and coated on a bare Cu substrate. Starting materials were metal-alkoxides as follows.; [$Bi(OC_{2}H_{5})_{3}\;Pb(O^{1}C_{3}H_{7})_{2},\;Sr(O^{i}C_{3}H_{7})_{2},\;Ca(OC_{2}H_{5})_{2}$] as a reagent grade. Transparent light yellowish sol was obtained in the case of $Bi_{1.9}Pb_{0.35}SrCaO\;and\;Bi_{1.8}Pb_{0.2}SrCaO$ composition and $Bi_{1.5}SrCaO$ composition's sol was light greenish. Each sol was repeatedly dip-coated on Cu substrate four times and pre-heated at $400^{\circ}C$ and finally heat-treated in the range of $740{\sim}900^{\circ}C$. In the results, crystalline phases confirmed by XRD were (2201) orthorhombic and monoclinic phases. However, only $Bi_{1.9}Pb_{0.35}SrCaO_{x}$ composition showed pseudo-superconductive behavior after heat-treatment at $900^{\circ}C$ for 12 seconds and then onset temperature was 77 K, even though it did not exhibit zero resistance below Tc.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1099-1103
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• 1999

The surface of an ${\alpha}$-alumina tube was coated with zirconium modified polycarbosilane(PZC) by dip-coating method. Then the tube was pyrolyzed at 573~823 K. The prepared inorganic composite membrane was in $1{\mu}m$ thickness and had no pinholes larger than several nm. For the pyrolyzed inorganic composite membrane, the permeation test of He, $N_2$, $CO_2$, and $O_2$ was performed at 303~423 K. The gas permeation and separation factor were increased with increasing permeation temperature. The permeation for gases was controlled by the activated diffusion mechanism. The separation factor of $CO_2$, to $N_2$was 4.9 at 363 K on the composite membrane pyrolyzed at 823 K and its value was higher than that of He and $O_2$.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.149-154
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• 1996

ZnO and Al-doped ZnO thin films were prepared by sol-gel dip-coating method and electrical and optical properties of films were investigated. Using the zinc acetate dihydrate and acetylaceton(AcAc) as a chelating agent stable ZnO sol was synthesized with HCl catalyst. Adding aluminium chloride to the ZnO sol Al-doped ZnO sol could be also synthesized. As Al contents increase the crystallinity of ZnO thin film was retarded by increased compressive stress in the film resulted from the difference of ionic radius between Zn2+ and Al3+ The thickness of ZnO and Al-doped ZnO thin film was in the range of 2100~2350$\AA$. The resistivity of ZnO thin films was measured by Van der Pauw method. ZnO and Al-doped ZnO thin films with annealing temperature and Al content had the resistivity of 0.78~1.65$\Omega$cm and ZnO and Al-doped ZnO thin film post-annealed at 40$0^{\circ}C$ in vacuum(5$\times$10-5 torr) showed the resistivity of 2.28$\times$10-2$\Omega$cm. And the trans-mittance of ZnO and Al-doped ZnO thin film is in the range of 91-97% in visible range.

• Korean Journal of Materials Research
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• v.22 no.11
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• pp.626-630
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• 2012

The properties of SOFC unit cells manufactured using the decalcomania method were investigated. SOFC unit cell manufacturing using the decalcomania method is a very simple process. In order to minimize the ohmic loss of flattened tube type anode supports of solid oxide fuel cells(SOFC), the cells were fabricated by producing an anode function layer, YSZ electrolyte, LSM electrode, etc., on the supports and laminating them. The influence of these materials on the power output characteristics was studied when laminating the components and laminating the anode function layer between the anode and the electrolyte to improve the output characteristics. Regarding the performance of the SOFC unit cell, the output was 246 $mW/cm^2$ at a temperature of $800^{\circ}C$ in the case of not laminating the anode function layer; however, this value was improved by a factor of two to 574 $mW/cm^2$ due to the decrease of the ohmic resistance and polarization resistance of the cell in the case of laminating the anode function layer. The outputs appeared to be as high as 574 and 246 $mW/cm^2$ at a temperature of $800^{\circ}C$ in the case of using decalcomania paper when laminating the electrolyte layer using the in dip-coating method; however, the reason for this is that interfacial adhesion was improved due to the dense structure, which leads to a thin thickness of the electrolyte layer.

• Journal of the Korean Magnetics Society
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• v.17 no.6
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• pp.226-231
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• 2007

High frequency loss property of nanocrystalline amorphous ribbon with a high resistivity insulation layer of $TiO_2$ and $SiO_2$ was studied. The insulation layer was fabricated by sol-gel method using dip-coating. The optimum composition ratio of metal alkoxide and slurry for fabrication of insulation layer was established and insulation layer with high adhesion was coated on the nanocrystalline amorphous ribbon. Frequency loss of magnetic core material manufactured on nanocrystalline amorphous ribbon with the surface insulation layer decreased over 40 % compared with that of magnetic core material without surface insulation layer. The insertion loss of an inductive coupler, which was prepared by using magnetic core material coated insulation layer, decreased due to reduction of frequency loss for magnetic core material and insertion loss decreased in proportion to frequency.

• Korean Journal of Optics and Photonics
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• v.24 no.5
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• pp.251-255
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• 2013

In this paper, the characteristics of a humidity sensor implemented by Mach Zehnder Interferometer (MZI) in a Planar Lightwave Circuit (PLC) have been designed and demonstrated. The humidity outside is detected with polyvinylpyrrolidone (PVP) coated on the etched arm of the MZI. The length of the etched arm is 10 mm and the PVP was coated by dip-coating into the etched region. As the refractive index of the PVP changes with the surrounding humidity, the PVP-coated humidity sensor presented changes in the interferogram depending on RH (Relative Humidity) around the PLC. The measured results show that the proposed humidity sensor works successfully in the range of 30% to 80% of RH.

• Journal of the Korean Ceramic Society
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• v.32 no.5
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• pp.617-625
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• 1995

In order to reduce reflectance of soda-lime glass having average reflectance of 7.35% and refractive index of 1.53, single (SiO2), double (SiO2/20SiO2-80ZrO2), and triple (SiO2/ZrO2/75SiO2-25ZrO2) layers were designed and fabricated on the glass substrate by Sol-Gel method. Stble sols of SiO2-ZrO2 binary system for antireflective (AR) coatings were synthesized with tetraethyl orthosilicate (TEOS) and zirconium n-butoxide as precursors and ethylacetoacetate (EAcAc) as a chelating agent in an atmosphere environment. Films were deposited on soda-lime glass at the withdrawal rates of 3~11 cm/min using the prepared polymeric sols by dip-coating and they were heat-treated at 45$0^{\circ}C$ for 10 min to obtain homogeneous, amorphous and crack-free films. In case of SiO2-ZrO2 binary system, refractive index of film increased with an increase of ZrO2 mol%. Designed optical constant of films could be obtained through varying the withdrawal rate. In the visible region (380~780nm), reflectance was measured with UV/VIS/NIR Spectrophotometer. Average reflectances of the prepared single-layer [SiO2 (n=1.46, t=103nm)], double-layer [SiO2 (n=1.46, t=1-4nm)/20SiO2-80ZrO2 (n=1.81, t=82nm)], and triple-layer [SiO2 (n=1.46, t=104nm)/ZrO2 (n=1.90, t=80nm)/75SiO2-25ZrO2 (n=1.61, t=94 nm)] were 4.74%, 0.75% and 0.38%, respectively.

• Journal of Fashion Business
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• v.21 no.6
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• pp.16-30
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• 2017

Currently, e-textile market is rapidly expanding and the emerging area of e-textiles requires electrically conductive threads for diverse applications, including wearable innovative e-textiles that can transmit/receive and display data with a variety of functions. This study introduces hybrid nano-structures which may help increase the conductivity of the textile threads for use in wearable and flexible smart apparels. For this aim, Ag was selected as a conductive material, and yarn treatment was implemented where silver nanowire (AgNW) and graphene flake (GF) hybrid structures overcome the limitations of the AgNW alone. The yarn treatment includes several treatment conditions, e.g., annealing temperature, annealing time, binder material such as polyurethane (PU), coating time, in order to search for the optimum method to form stable conductive nano-scale composite materials as thin film on the surface of textile yarns. Treatedyarns showed improved electrical resistance readings. The functionality of the spandex yarn as a stretchable conductive thread was also demonstrated. When the yarn specimens were treated with colloid of AgNW/GF, relatively good electrical conductivity value was obtained. During the extension and recovery cycles of the treated yarns, the initial resistance values did not deteriorate significantly, since the network of nanowire structure with the support of GF and polyurethane stayed flexible and stable. Through this research, it was found that when one-dimensional structure of AgNW and two-dimensional structure of GF were mixed as colloids and treated on the surface of textile yarns, flexible and stretchable electrical conductor could be formed.

• Journal of the Korean GEO-environmental Society
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• v.20 no.11
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• pp.5-10
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• 2019

For the development of long-wavelength responding photocatalyst, Ag was applied to commercial $TiO_2$ to produce $Ag/TiO_2$ photocatalyst. Moreover, micro-emulsion method was used in order to increase the efficiency of the photocatalyst by enhancing the dispersion of Ag. Physical properties of the manufactured catalyst were analyzed by scanning electron microscopy (SEM), field emission transmission electron microscopy (FE-TEM) and diffuse reflectance spectroscopy (DRS). For the catalytic performance measurement, RO 16 (Reactive Orange 16) removal was performed with 25 ppm RO 16 under UV-A (365 nm) irradiation. In addition, ball milling and dip-coating method were used to synthesize the photocatalyst for the comparison of the outcomes of using different synthesis methods. In addition, catalytic performance was improved by varying the Ag content and surfactant content. The highest catalytic performance was shown at $Ag/TiO_2$ synthesized by micro-emulsion method with 2 wt% of Ag content, and 0.5 g of the surfactant.