• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.68-68
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• 2018

Nanoporous or nanotubular metal oxide can be fabricated by anodization of metal substrate in fluoride contained electrolytes. The approach allows various transition metals such as Zr, Hf, Nb, Ta to form highly ordered oxide nanostructures. These oxide nanostructures have various advantages such as high surface area, fast electron transport rate and slow recombination in semiconductive materials. Recently, vanadium oxide nanostructures have been drawn attentions due to their superior electronic, catalytic and ion insertion properties. However, anodization of vanadium metal to form oxide layers is relatively difficult due to ease formation of highly soluble complex in water contained electrolyte during anodization. Yang et al. reported $[TiF_6]^{2-}$ or $[BF_4]^-$ in electrolyte helps to formation of stable oxide layer [1, 2]. However, the reported approaches are very sensitive in other parameters. In this presentation, we deal with the other important key parameters to form ordered anodic vanadium oxide such as pH, temperatures and applied potential.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.491-493
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• 2000

The performance of insulate materials gets worse with stress time in power system and because this causes lowering of function and accidents in equipment, development and performance improvement of excellent insulate materials are needed to make stable system. In this paper, to study the influence of degradation in XLPE, inner semiconducting layer and outer semiconducting layer, we studied dielectric characteristics at temperature $25{\sim}100[^{\circ}C]$ and frequency $20{\sim}1[MHz]$ and volume resistivity at temperature $25{\sim}100^{\circ}C$, voltage.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2133-2135
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• 1998

Many semiconductive switches are operated in series for high voltage operation. The same number of gate drivers are needed to control all the switches, hence, the drivers cause high cost and system complexity. In this study, a simple and low cost gate driver for high voltage thyristor-diode switches is investigated. This gate driver can operate several high voltage thyristor-diode switches at the same time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.163-166
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• 1998

In this paper, breakdown strength and dielectric characteristics were experimented in the structures of insulation/insulation/insulation and insulation/semiconductor/insulation by using of insulation material of polyethylene terephthalate film. The breakdown strength and the permitivity of each specimen were measured as a function of temperature and frequency respectively. The breakdown strength of PET/PET/PET did not changed greatly but that of PET/SEMl/PEr increased as a function of temperature. As the frequency inclosed, the permitivity of PET/PET/PET and PET/SEMI/PET decreased. The tan $\delta$ of PET/PET/PET showed lower than that of PET/SEMl/PET in low frequency but higher in high frequency .

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1649-1654
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• 2003

We have investigated substituent effect on the stabilization energies, and nucleus-independent chemical shifts of pentafulvalenes and on the electronic structures of the corresponding polypentafulvalenes to design environmentally stable semiconductive or conductive polymers. Geometrical optimizations of the molecules were carried out at the density functional level of theory with B3LYP hybrid functional and 6-311+G(d) basis set. Stabilization energies were estimated using isodesmic and homodesmotic reactions. As a criterion of aromaticity nucleus-independent chemical shifts of the molecules were computed using GIAO approach. For the polymers the geometrical parameters were optimized through AM1 band calculations and the electronic structures were obtained through modified extended Huckel band calculations. It is found that strong electronwithdrawing substituents increase isodesmic and homodesmotic stabilization energies of pentafulvalene, though it does not increase the aromaticity. Nitro-substituted pentafulvalene is estimated to have stabilization energy as much as azulene. However, substitution either with electron-donating groups or with electronwithdrawing groups does not significantly affect the electronic structures of polypentafulvalene and poly (vinylenedioxypentafulvalene).

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.57-63
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• 2011

Photovoltaic effect is confirmed in DSSC fabricated under the common conditions. In upper electrodes, validity of ZnO as new TCO material was investigated and an improvement of characteristics in DSSC was tried by control of process conditions at semiconductive powder layer. ZnO thin film showed very high resistivity, therefore efficiency of solar cell was lower than that of conventional ITO-related material. DSSC characteristics was able to improve by thin blocking layer doposited between the TCO and semiconductor layer.

• Journal of information and communication convergence engineering
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• v.1 no.1
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• pp.31-34
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• 2003

Sol-gel processing of $BaTiO_{3}$ ceramics doped with La (0.01∼1.00 at.%) were prepared from metal barium, titanium n-butoxide and lanthanum isopropoxide. Characterization of the sol-gel-derived powder using XRD, SEM is also reported. The obtained results suggested that insulator to semiconductor transition for highly donor-doped barium titanate was closely related to the incorporation of donor into the grains and to the resultant grain size, which were significantly affected by the sinterability of $BaTiO_{3}$ powders and sintering conditions used.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.73-76
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• 2000

The performance of insulate materials gets worse with stress time in power system and because this causes lowering of function and accidents in equipment,development and performance improvement of excellent insulate materials are needed to make stable system. In this paper, to study the influence of degradation in XLPE, inner semiconducting layer and outer semiconducting layer, we studied dielectric characteristics at temperature 25∼100[$^{\circ}C$] and frequency 20∼ 1 [MHz]

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.223-223
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• 2007

Thermal and mechanical properties were investigated in several semi-conductive materials which is composed of carbon black and polymer. EVA, EEA, and EBA is normally used for matrix polymer and normally acetylene black and furnace black is used. Isothermal thermo gravimetric analysis is done as a function of atmosphere and temperature. In nitrogen atmosphere semicon compound was slowly degradaded but in ambient condition degradaded fast. So in the cable manufacturing, atmosphere and materials are very important.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1343-1344
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• 2007

In this paper, we investigated mechanical characteristics about thermal properties in semiconductor layer of power cables. Method of specimen making used solution mixing and Tensometer 2000 of Alpha used for measurement of stress and strain. Semiconductor layer made an experiment on separately environmental temperature$[25^{\circ}C]$ and high temperature$[90^{\circ}C]$ which running temperature$[90^{\circ}C]$ of cables exposed. As a result, specimen of applicable DFS(Dual Filler System) could know mechanical superiority that its structural characteristics reinforcement considered thermal characteristics.