• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.234-236
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• 2003

The cryogenic system for inductive superconducting fault current limiter (SFCL) has been investigated recently. In this investigation, the sub-cooled nitrogen cryogenic system was adopted to enhance the performance of DC reactor for 6.6㎸/200A inductive SFCL. In sub-cooled nitrogen state at 64K, the critical current value and the thermal conductivity are larger than those of saturated nitrogen state at 77K and the electrical insulation capacitance should be remarkably enhanced. The solenoid type of 84mH superconducting DC reactor was fabricated and cooled down to 64K by using sub-cooled cooling method with GM-cryocooler and rotary pump. The fabrication techniques of cryogenic system and some experimental results such as cooling down characteristic are introduced in this study. Moreover, the sub-cooled nitrogen cryogenic system was detailedly introduced in this paper.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.425-428
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• 1999

In this paper, the electrical properties of Pt/YMnO$_3$/Si(100) structures with difference rapid thermal annealing (RTA) treatment were investigated. YMnO$_3$films were obtained without buffer layers, introducing oxygen. A typical value of the dielectric constant was about 20 derived from 1MHz capacitance-voltage (C-V) measurement and the resistivity of the film at the field of 150kV/cm was about 1.34$\times$10$^{12}$ $\Omega$ . cm. The minimum interface state density around midgap was estimated to be about 5$\times$10$^{11}$ cm$^2$. eV.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.143-146
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• 1999

In this study, Ultra-thin films of (N-ducosyl quinolinium)-TCNQ(1:2) complex were prepared on the hydrophilic substrate by Langmuir-Blodgett(LB) technique. By measure of UV-vis spectra and capacitance, deposition status was confirmed together with the thickness of natural oxidized aluminum film inside a device and dielectric constant of (N-docosyl quinolinium)-TCNQ(1:2) complex. The electrical properties of (N-docosyl 7uin7linium)-TCNQ(1:2) complex were investigated at room temperature. The conductivity of this film measured by the direction uf either vertical or horizontal axis is results in a quite different value.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.938-940
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• 2004

With increased emphasis on non-conventional energy system and autonomous power generation, development of improved and appropriate generating system has assumed signification. This paper describes the performance analysis of 2-phase self-excited induction generators. The minimum capacitance of self-excited capacitor connected auxiliary winding is determined the suitable value using circuit equations of auxiliary winding. For the steady state analysis, the equivalent circuit of 2-phase induction generators is used as circuit modeling using the double-revolving field theory. The validity of designed generator system will be confirmed by experimental and computed results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1366-1367
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• 2006

Embedded capacitor technology is one of the effective packaging technologies for further miniaturization and higher performance of electric package systems. So we used the 3D EM simulator for embedded capacitor design in 8-layed PCB(Printed Circuit Board). The designed capacitors value are 2 pF, 5pF, 10 pF, respectly. we investigated characteristics of capacitance - frequency and SRF(Self Resonance Frequency) as changing the rate of hight and width of upper pad of embedded capacitors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.218-220
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• 1996

This paper was evaluated dielectric characteristics and temperature dependency in the XLPE with and without void. Each dielectric loss was $3.5{\times}10^{-4}$(%) and a little decreased with temperature's increase. Capacitance presented a contant value. According as the study is obtained results, loss in the XLPE increased in proportion to square of applied voltage. As a result of the study, it was knowed that dielectric characteristics had a great deal to do with degradation in the high voltage dielectric materials.

• 한국진공학회지
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• 제8권3A호
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• pp.218-223
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• 1999

We investigated the interfacial reactions between the $Y_2O_3$ film deposited by ICB processing and p-type (100) Si substrates upon annealing treatments in $O_2$ and Ar gas ambients. we also investigated the evolution of surface morphology of ICB deposited $Y_2O_3$ films upon annealing treatments. We observed that the root-mean-square(RMS) value of surface roughness measured by AFM increased with annealing time at $800^{\circ}C$ in $O_2$ ambient, while the change of surface roughness was not observed in Ar ambient. We also found the growth of $SiO_2$ layer and the formation of yttium silicate layer. From the capacitance values $(C_{acc})$ measured by C-V measurements, the relative didldctric constant of $Y_2O_3$ film in metal-insulator-semiconductor(MIS) structure was estimated to be about 9.

• Tribology and Lubricants
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• 제22권2호
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• pp.99-104
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• 2006

The dielectric constants of fresh engine oils were obtained according to various types of oil, temperatures and frequencies. Through analyzing the characteristics of dielectric constant, the related correlation between the changes in dielectric constant of oil and the degree of oil deterioration is going to be found. The dielectric constant was calculated by cross capacitances measured by a sensor tube. Before finding the correlation, as a prerequisites study, the best condition measuring the dielectric constant was found. In general, it was found that the value of dielectric constant became stable below $60^{\circ}C$ regardless frequency variation. Further, above 6kHz, the dielectric constant became stable even if temperature had been above $100^{\circ}C$.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.129-139
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• 2018

The effects of N doping concentration and dopant moieties on the electrochemical properties of nanoporous graphene and their dependence on annealing temperature are investigated. Four types of N moieties - amide, amine, graphitic-N, and oxidized-N - are obtained, which transformed into pyridinic-N and pyrrolic-N upon annealing. The diffusion coefficient (D') of the ions in the electrode is the maximum at $400^{\circ}C$ because of a high level of N doping, whereas the second highest D0 value is obtained at $700^{\circ}C$ owing to a high level of reduction and N doping. The highest specific capacitance is obtained for the sample annealed at $400^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1049-1055
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• 1999

Electrochemical oxidation of silicon (p-type Si(100)) at room temperature in ethylene glycol and in aqueous solutions has been performed by applying constant low current densities for the preparation of thin SiO2 layers. In-situ ac impedance spectroscopic methods have been employed to characterize the interfaces of electrolyte/oxide/semiconductor and to estimate the thickness of the oxide layer. The thicknesses of SiO2 layers calculated from the capacitive impedance were in the range of 25-100Å depending on the experimental conditions. The anodic polarization resistance parallel with the oxide layer capacitance increased continuously to a very large value in ethylene glycol solution. However, it decreased above 4 V in aqueous solutions, where oxygen evolved through the oxidation of water. Interstitially dissolved oxygen molecules in SiO2 layer at above the oxygen evolution potential were expected to facilitate the formation of SiO2 at the interfaces. Thin SiO2 films grew efficiently at a controlled rate during the application of low anodization currents in aqueous solutions.