• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.56-63
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• 2001

The thermal stability conditions are investigated for superconducting magnet systems cooled conductively by cryocooler without liquid cryogens. The worst scenario in the systems is that the heat generation in the resistive state exceeds the refrigeration. causing a rise in the temperature of the magnet winding and leading to the burnout. It is shown by an analytical solution that in the continuous resistive state, the temperature may increase indefinitely or a stable steady-state may be reached, depending upon the relative size of the magnet with respect to the refrigeration capacity of the cryocooler. The stability criteria include the temperature-dependent Properties of the magnet materials and the refrigeration characteristics of the cryocooler. A useful graphical scheme is Presented and discussed to demonstrate the physical importance of the results.

• 한국세라믹학회지
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• 제31권8호
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• pp.886-892
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• 1994

Structural and electrical properties of BaTiO3 thin films deposited on Pt/SiO2/Si substrates by RF magnetron sputtering method have been investigated. Crystallization behavior and electrical properties were studied for the films deposited under various sputtering gas compositions (Ar+O2 gas mixture) and substrate temperatures. All the films deposited above 50$0^{\circ}C$ were all crystallized and their preferred orientation changed from (001) to (111) with the addition of oxygen gas. The dielectric constant of films deposited in pure argon was about 110 and showed little dependence on the substrate temperature. But that was increased as the ratio of O2/Ar increased and its substrate temperature dependence was discernible. The highest dielectric constant reached to 550. In addition, the films deposited in mixed gas showed stable dielectric properties against the frequency and temperature.

• 한국안전학회지
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• 제18권1호
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• pp.14-18
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• 2003

The structural development of air-water bubble plumes has been measured under different condition on air flow rate in a cylindrical bath. The time-averaged structure of plumes has been measured with an oscilloscope and an electro-conductivity probe. The temperature of bubbles was also obtained by a thermal-infrared camera. Gas volume fraction and bubble frequency were high since bubbles concentrated on the nozzle. In general, their axial and radial values tended to decrease with increasing distance. Bubble temperature reached water temperature within a short time. The present study showed that thermal equilibrium between bubbles and water was completed before bubbles flow became stable.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권3호
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• pp.105-108
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• 2003

In this work, a Voltage-to-Frequency Converter(VFC) in which the output frequency is proportional to the input voltage is proposed. To obtain the temperature stable characteristics of the VFC circuit is designed by BiCMOS technology. The output frequency range is 24KHz to 65KHz and the difference between simulated and calculated values is less than about 5% for this range of output frequency. The temperature variation of sample output frequencies is less than $\pm$0.5% in the temperature range $-25^{\circ}C$ to 75$^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.566-569
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• 2002

The $(Sr_{0.9}Ca_{0.1})TiO_3$(SCT) thin films are deposited on Pt-coated electrode (Pt/TiN/$SiO_2$/Si) using RF sputtering method. The maximum dielectric constant of SCT thin film is obtained by annealing at $600[^{\circ}C]$. The temperature properties of the dielectric loss have a value within 0.02 in temperature ranges of $-80{\sim}+90[^{\circ}C]$. The capacitance characteristics had a stable value within ${\pm}4[%]$. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films is observed above 200[kHz].

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기설비전문위원
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• pp.97-99
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• 2004

Liquid-immersed pole transformers have utilized an insulation system consisting of natural cellulose-based materials and mineral oil for many years. If the transformers are installed with the abruptly changing load over limitation, its insulation materials are apt to unexpected aging with high temperature. Therefore we have been conscious of developing a transformer that is more thermally stable then conventional types. To measure temperature distribution in the winding of conventional and newly designed transformers, temperature sensors were installed fordirect reading of oil and conductor temperatures at transformers. And we conducted accelerating aging test for these transformers. The measuring data had made use of the design to hybrid insulation system. Also we could find the possibility of this insulation system to apply in pole mounted transformers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.585-588
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• 2001

Thin. Boron-doped conducting diamond films are expected to be excellent electrodes for industrial electrolysis. Boron-doped conducting diamond films were used as anode for generating ozone gas by electrolysis of acidic solution. In this work, we have studied ozone generating system using Boron-doped Diamond electrode. Electrochemical cell and ozone generating system were designed for decreasing the temperature of the system. which was elevated during the reaction. by circulation of electrolyte in the system. In order to determine the ozone generation properties of diamond electrode. experimental conditions, electrolyte concentration, temperature, flow rate and reaction time were varied diversely. As a result, we could confirm that ozone gas was generated successfully and the performance of diamond electrode was stable while $PbO_2$ electrode was disintegrated. Actually we are found that ozone amount increased by lowering the temperature of electrolyte.

• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1019-1023
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• 2005

We have examined the electrical and optical characteristics of the plasma display panel produced by vacuum in-line sealing technology. In the MgO layer deposited at room temperature, after sealing at the panel temperature of $430^{\circ}C$, the luminous efficiency decreased compared with that of the panel before sealing. Moreover, firing and sustain voltage of the sealed panel increased compared with that of the panel before sealing. This was resulted from that the MgO protective layer was cracked by the softening of the dielectric layer during the sealing process. In order to avoid the MgO crack during the vacuum in-line sealing, thermally stable MgO layer or lower temperature sealing is required.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.225-228
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• 2008

The electricity supply and demand to be stable to a system link increase of the variance power supply and operation are requested in jeju Island electricity system. A short-term Load forecasting which uses the characteristic of the Load is essential consequently. We use the interrelationship of the electricity Load and change of a summertime temperature and data refining in the paper. We presented a short-term Load forecasting algorithm of jeju Island and used the correlation coefficient to the criteria of the refining. We used each temperature area data to be refined and forecasted a short-term Load to an exponential smoothing method.

• 한국분무공학회지
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• 제3권4호
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• pp.16-24
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• 1998

The fuel injection type, in the gasoline engines of atomization of fuel droplet and its distribution hae influenced directly on the decision of engine performance and harmful emission. In this paper, atomization characteristics of fuel spray is investigated with microscopic visualization system. Particle motion analysis system is used to measure the SMD from fuel spray of air-assisted injector by initial factors such as temperature of ambient air and air-assisted pressure. As air-assist pressure and ambientair temperature increase, the SMD is decreased, and its variation is more stable.