• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.360-363
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• 2005

Biomimetic actuators composed of cellophane with an electrically conducting polyaniline(PANI) film have been fabricated and tested in air ambience conditions doped with two different counter ions such as perchlorate (${ClO_4}^-$) and tetrafluoroborate (${BF_4}^-$). Fabrication of the trilayer CP//CELLOPHANE//CP substantially enhanced the tip displacement (13.2mm) compared to the small displacement (8.3mm) of the bilaye. CP//CELLOPHANE. The ion migration among layers is the main factor behind the expansion of cellophane, while the expansion/contraction of PANI are dependent on the redox reaction of the polymer. The displacement of the composite is dominated by the humidity content. This implies that the actuation principle is possibly due to the assistance of water existing.

• Carbon letters
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• v.1 no.3_4
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• pp.133-137
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• 2001

Mesoporous activated carbon fiber (ACF) was prepared from phenolic resin containing a small amount (0.1 wt %) of organic nickel complex through carbonization and steam activation. Microporous ACF as reference sample was also prepared from phenolic resin without agent. In both cases of the mesoporous ACFs and the microporous ACFs, the electric double layer capacitance of the nonaqueous electrolyte (0.5 M $TEABF_4$/PC or 1.0 M $LiClO_4$/PC) was not proportional to the BET specific surface area. This is owing to the low permeability of nonaqueous electrolyte or the low mobility of ion in narrow micropores. However, the mesoporous ACF showed higher double layer capacitance than the microporous (normal) ACF. This result suggests that the presence of many mesopores promotes the formation of effective double layer or the transfer of ion in the micropore.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.157-157
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• 1999

Electrochromic tungsten oxide films were prepared by the electron beam deposition, and the dependence of the electrochemical stability and the optical properties on the titanium concentration, and on the annealing temperature, that was investigated. coloring and bleaching experiments were repeated by cyclic voltammetry in a propylene carbonate solution of LiClO4. Spectrometry was used to assess the stability of the transmittance in the degraded films. Tungsten oxide films with titanium contents of about 10~15 mol% were found to be most stable, undergoing the least degradation during the repeated for coloring and bleaching cycles. The reason for this small amount of degradation was the reduction of lithium ion trapping sites in the films, which results in an increased durability. Tungsten oxide films with titanium contents of about 20 mol% were annealed at 20$0^{\circ}C$ for 1 hour, and this results showed that durability of films were increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.76-79
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• 1996

Polypyrrole films were electrochemically synthesized under a constant current condition ranging from 50 ${\mu}$A/$\textrm{cm}^2$ to 2 mA/$\textrm{cm}^2$ with resultant high electrical conductivity about 100 S/cm. Specific energy of 70 Wh/kg and Ah efficiency of 97% were achieved during the cycling using liquid electrolyte system. On the other hand, consequences of the cycling were 51 Wh/kg and 95% using PEO$\sub$8/LiClO$_4$PC$\sub$5/EC$\sub$5/ solid electrolyte system. Polypyrrole film can be cycled stable and Ah efficiency is excellent, so it can be applicable to the cathode of Lithium secondary batteries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.764-769
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• 2000

The purpose of this study is to research and develop conducting polymer(CP) composite electrode for supercapacitor. Supercapactior cell of CP composite electrode with 1M LiClO$_4$/PC brings out good capacitor performance below 4V. The radius of semicircle of CP composite cell with PAn composite electrode adding 15Wt% SP270(PAnS15) and PT composite electrode adding 50%wt% SP270(PTS50) was absolutely small. The total resistance of supercapacitor cell mainly depended on internal resistance of the electrode. The discharge capacitance of supercapacitor cell with PTS50(+)/PAnS15(-) in 1st and 20th cycles was 38F/g and 28F/g at current density of 1mA/$\textrm{cm}^2$, respectively.

• Analytical Science and Technology
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• v.8 no.4
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• pp.631-636
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• 1995

Electrochemical properties of self-dopable poly(aniline N-butylsulfonate)s in various acidic medium were investigated by spectroelectrochemical techniques. Cyclic voltammetric study showed more than two reversible process of one electron transfer, the potential and peak intensity of which were dependent on the acid concentration and dopant ion. Spectroscopic study at different oxidation level indicated that the electrochromic switching of the poly(aniline N-alkylsulfonate)s film involves structural changes from benzenoid ring to quinoid ring. Spectrocyclic voltammetry together with impedance spectra of the PANBUS film in 0.1 M $LiClO_4$ solution of acetonitrile containing 0.46 M of perchloric acid showed two types of highly conductive states at the intermediate oxidation levels, which can be related to the metallic polaron states doped by two different process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.105-108
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• 1996

The positive active material for polymer film battery was prepared by using Polyphenylenediamine(PPD) synthesized in our lab. and 2.5-dimercapto-1, 3, 4-thiadiazole(DMcT) in various mixture ratio. The transference measurement of surface morphology and thermal stability of prepared composite film was carried out by using SEM and TGA, respectively. Electrocyhemical property and electrical conductivity of composite film were also measured by using cyclic voltammetry and four-probe method in dry box, respectively. The thermal stability of prepared composite film is more than 20$0^{\circ}C$. The electrical conductivity of composite film increased and showed the highest value(about 3 S/cm)when doped at 0.4% LiClO$_4$solution. And we could confirm that DMcT effect on reactiviation of PPD through cyclic voltammogram.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.4
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• pp.323-327
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• 2001

The purpose of this study is to research and develop conducting polymer(CP) composite electrode for supercapacitor. The radius of semicircle of CP composite cell with polyaniline(PAn) composite electrode adding 30wt% acetylene black was small. The total resistance of supercapacitor cell mainly depended on internal resistance of he electrode. The discharge capacitance of supercapacitor cell with PAn composite electrode adding 30wt% acetylene black in 1st and 50th cycles was 27F/g and 31F/g at current density of 1mA/$\textrm{cm}^2$, respectively. Supercapacitor cell with PAn composite electrode adding 30wt% acetylene black showed a good cycliability. Supercapacitor cell of CP composite electrode with 1M LiClO$_4$/PC brings out god capacitor performance below 4V.

• Solar Energy
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• v.16 no.2
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• pp.87-96
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• 1996

Electochromic tungsten oxide thin films were prepared on the ITO coated glass by rf magnetron sputtering from a compressed powder tungsten oxide target in an argonoxygen atmosphere. The influence of the preparation conditions, especially the substrate temperature, on the chemical stability of film was investigated. These films were cycled in 0.6M $LiClO_4$ and 0.6M $H_2SO_4$ electrolyte respecitively, and exhibited electrochromic behavior upon the electrochemical insertion and extraction of ion. Among these tungsten oxide thin films, films prepared at a substrate temperature of $150^{\circ}C$ were found to be most stable in terms of cyclic durability.

• Solar Energy
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• v.19 no.1
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• pp.1-8
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• 1999

Electrochromic $WO_3$ thin films were prepared by electron beam deposition. The transmission and durability of films were investigated. Coloring and bleaching experiments were repeated in an electrolyte of propylene carbonate with 0.6M of $LiClO_4$ by cyclic voltammetry. Spectrophotometer was used to measure the transmission in the degraded films. The 5000 ${\AA}$ thick film was found to be the stable after repeated cycles. The durability of the annealed film also showed improvements over unannealed samples. Tungsten oxide films with titanium content of about $10{\sim}15$ mol% was found to be most stable, undergoing the least degradation during the repeated cycles.