• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.53-58
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• 2001

Solar energy has many advantage like as purity and infinity. Recently many researches about new energy source are processing in several places around the world. In this paper, the virtual implement of solar cell was proposed to solve the problems as reappearance and repetition of some situation in experiment of photovoltaic. To realize the VISC, mathematical model of solar cell for driving converter was studied and the buck converter were compared in viewpoint of tracking error of characteristic curve of solar cell using computer simulation. Also, Output characteristics of system analyzed through an experiment.

• Progress in Superconductivity and Cryogenics
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• v.15 no.3
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• pp.9-12
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• 2013

Current-voltage characteristic models of superconducting material are suggested by many researchers. These current-voltage characteristic models are important because they can be used for design or simulation of superconductor devices. But widely used current-voltage models of superconductor wire still have some limitations. For example, a standard E-J power model has no parameters related with stabilizer's resistance in superconductor wire. In this paper, a current-voltage characteristic modeling method for high temperature superconductor (HTS) tape with considering the effect of stabilizer is introduced. And a current-voltage characteristic of a HTS tape is measured under different stabilizer conditions. Those measured current-voltage characteristics of the HTS tape modeled with proposed modeling method and the modeling results are compared.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1679-1681
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• 1996

ZnO varistor with composition of 89wt%-ZnO, 3.0wt%-$Bi_{2}O_{3}$, 3.6wt%-$Sb_{2}O_{3}$, 1.16wt%-CoO, 0.88wt%-NiO, 0.71wt%-$MnO_2$, 0.93wt%-$Cr_{2}O_{3}$, 0.013wt%-$Al_{2}O_{3}$ was fabricated by sintering methods. The effects of annealing on the J-E characteristics of ZnO varistors were investigated. These changes of electric properties were found to be caused by the variation of grains and grain boundary related to annealing. And the conductive mechanism and micostructure of ZnO varistor were researched using I-V meter, SEM and XRD.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.480-483
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• 1987

Investigation has been carried out on the characteristics of thermally stimulated current for PVDF (polyvinylidene flouride) film, using Data Acquisition system, in the temperature range from -100[$^{\circ}C$] to 20[$^{\circ}C$]. The peaks observed, two of the diatinguished peaks such as $\delta$, $\gamma$ each of which appeared at -39[$^{\circ}C$] and -15[$^{\circ}C$] respectively. Their peaks exhibited by the depolarization in amorphous region. It proposed new numerical method for analysis of TSC spectra.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1758-1760
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• 1997

Automatic detection system to detect acoustic emission pulse and fractal dimension were developed, to observe tree deterioration phenomena in LDPE. The purpose of our work are to use acoustic emission system and fractal dimension and to investigate the treeing phenomena in polymeric insulation under applied AC voltage 11[kV] with an artificial needle-shaped void(1.5[mm]) using the above system. We analyzed and phase angle-acoustic emission pulse amplitude-deterioration time ($\Phi$-AEA-t) pattern and phase angle-acoustic emission pulse number-deterioration time($\Phi$-AEN-t) pattern using statistical operators such as skewness, fractal dimension. In this paper show that the correlation of $\Phi$-AEA-t, $\Phi$-AEN-t, fractal dimension using regression analysis by the method of least squares can be used to predict the breakdown just before the breakdown occurs.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.157-161
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• 1999

A Ti:Sapphire laser pumped by the HCP has been designed and fabricated to study the optimal pumping conditions for lasing. The fluorescence energy converter LD-490 has been used. The result showed that the threshold energy of Ti:Sapphire laser is 1.39 KJ and the best efficiency is $7.13{\times}10^{-3}$% at the concentration $1.0{times}10^{-3}$ Mol/l of LD-490 dye. However, the efficiencies were decreased with the decrease of dye concentrations. The maximum output energy was obtained at 50 Torr Ar pressure, when the input voltage was 15 kV. As a convert dye, BBQ, was added to LD-490 with the rate of 1:1, the output energy was increased, whereas the thereshold energy was decreased as 1.17 kJ.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.180-186
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• 2018

We report the discovery of Li-rich $Li_{1+x}[(Ni_{0.225}Co_{0.15}Mn_{0.625})_{1-y}V_y]O_2$ as a cathode material for rechargeable lithium-ion batteries in which a small amount of tetravalent vanadium ($V^{4+}$) is selectively and completely incorporated into the manganese sites in the lattice structure. The unwanted oxidation of vanadium to form a $V_2O_5-like$ secondary phase during high-temperature crystallization is prevented by uniformly dispersing the vanadium ions in coprecipitated $[(Ni_{0.225}Co_{0.15}Mn_{0.625})_{1-y}V_y](OH)_2$ particles. Upon doping with $V^{4+}$ ions, the initial discharge capacity (>$275mA\;h\;g^{-1}$), capacity retention, and voltage decay characteristics of the Li-rich layered oxides are improved significantly in comparison with those of the conventional undoped counterpart.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1132-1136
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• 2004

In this paper, we intend to make FFS mode cell with LC alignment used non-rubbing method, ion beam alignment method on the a-C:H thin film, to analyze electro-optical characteristics in this cell. We studied on the suitable inorganic thin film for FFS-LCD and the aligning capabilities of nematic liquid crystal (NLC) using the new alignment material of a-C:H thin film as working gas at rf bias condition. A high pretilt angle of about 5$^{\circ}$ by ion beam(IB) exposure on the a-C:H thin film surface was measured. An excellent voltage-transmittance (V-T) and response time curve of the ion-beam-aligned FFS-LCD was observed with oblique ion beam exposure on the DLC thin films.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.72-75
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• 2001

The solar energy is purity and infinity. Solar power converter were used to convert the electrical energy from the solar arrays to a stable and reliable power source. So much country research this solar energy system. The photovoltaic system is construct many solar cell array, In this paper, new implementation solar system was showed buck converter that V-I curve produced. This system can be used to study the short-term and long-term performances of solar cell and efficiency. This system is a far more cost effective and reliable replacement for field and outdoor flight testing. Study of buck converter, analysis and control shun t$\cdot$series connection characteristics of solar cell array.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1414-1417
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• 1996

The purpose of this study Is to research and develop $V_{6}O_{13}$ composite cathode for lithium thin film battery. $V_{6}O_{13}$ represents a class of cathode active material used in Li rechargeable batteries. In this study, we investigated cyclic voltammetry and charge/discharge characteristics of $V_6O_{13}$/SPE/Li cells. Cyclic voltammogram of $V_{6}O_{13}$/SPE/Li cell at scan rate 1mV/sec showed reduction peaks of 2.25V and 2.4V and oxidation peaks of 2.4V and 2.2V. The discharge curve of $V_{6}O_{13}$/SPE/Li cell showed 4 potential plateaus. The discharge capacity was decreased in the beginning of charge/discharge cycling. After 8th cycling, the discharge capacity was stable. The discharge capacity of 1st cycle and 15th cycle was 290mAh/g and 147mAh/g at $25^{\circ}C$, respectively.