• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.1
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• pp.45-53
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• 2006

Thermal insulation is used in a variety of applications to protect temperature sensitive products from thermal damage. Several factors affect the performance of insulation packages. Among these factors, the thermal resistance of the insulating wall is the most important factor to determine the performance of the insulating package. In many cases, insulating wall consists of multi-layered structure and the heat transfer through this structure is a very complex process. In this study, an one-dimensional mathematical model, which includes all of the heat transfer principles covering conduction, convection and radiation in multi-layered structure, were developed. Based on this model, several heat transfer phenomena occurred in the air space between the layer of the insulating wall were investigated. From the simulation results, it was observed that the heat transfer through the air space between the layer were dominated by conduction and radiation and the low emissivity of the surface of each solid layer of the wall can dramatically increase the thermal resistance of the wall. For practical use, an equation was derived for the calculation of the thermal resistance of a multi-layered wall.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.8
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• pp.411-416
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• 2006

A new method on the evaluation of insulation oil was proposed. Terahertz time-domain spectroscopy (THz-TDS) was applied to investigate the properties of the insulating oil. For the diagnostics of oil degradation, three kinds of oils have been analyzed by THz-TDS. The degraded oil showed different optical and electrical constants compared with a new one. Generally, the power absorption coefficient, the refractive index, the dielectric constant and loss $tan{\delta}$ of the oil increase as the aging of insulating oil proceed. And the characteristics of two kind of insulation oil, 1-4 and 7-4, was compared in terahertz spectral region. Difference in refractive index and complex dielectric constant has been observed between the samples. The results of this study suggest that THz-TDS is a promising new means for evaluating degradation and identification of insulating oil.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1637-1639
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• 2001

Air arc interruption used in low rated voltage breaker, ACB and MCCB, have used the arc chamber composed of metal plates and insulating laminates which supposed these mechanically. and geometry and materials of arc chamber are very different by breaker manufacturer. These breakers have required to be smaller and to interrupt higher current by user. therefore the arc chamber geometry and material in breaker have been small, complex and various. The purpose of this study is to examine the effects of insulating laminates and contact materials on air arc interruption. Contacts were surrounded by a rectangle chamber of insulating laminates. Contact concoctions were composed of AgW, AgCdO that have used in low rated voltage breaker, and insulating laminates were polyester, epoxy. We found strong dependance of arc voltage on insulating material. The ablated vapor on polyester increased arc voltage that was useful in air arc interruption.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.938-940
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• 1998

In order to improve insulating character and ability of insulating system of power apparatus, the interfacial and complex structure is widely used. However, the interface or complex structure of insulation materials is reported as a weak point which causes breakdown. As the interface of insulation system degrades its electrical property and eventually causes a failure, the datailed phenomenon analysis is reported. The object of this paper is to evaluate dielectric property of PET film with the interface. The $tan{\delta}$ increased with the existence of semiconducting layer and showed prominent decrease as a function of temperature. Also, the $tan{\delta}$ showed prominent increase as a function of frequency. The dielectric properties of interfacial were affected by the interface characteristics.

• Electrical & Electronic Materials
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• v.7 no.5
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• pp.383-388
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• 1994

Deep levels in semi-insulating GaAs were observed by thermally stimulated current(TSC) measurement In the temperature ranges of 100-300K Tl(E$\_$c/-0.18eV), T2(E$\_$c/-0.20eV), T3(E$\_$c/-0.31eV), T4(E$\_$c/-0.40eV), and T5(E$\_$c/-O.43eV) traps have been observed. The TI, T2, and T5 traps seem to be related to the V$\_$As/, V$\_$Ga/-complex, and As$\_$Ga/$\^$++/ respectively. T4 trap is considered with respect to V$\_$Ga/-V$\_$As/ complex.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.426-433
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• 1995

Effect of boron in GaAs have been investigated by photo induced current transient spectroscopy(PICTS). The starting material was undoped liquid encapsulated Czochralski(LEC) semi insulating GaAs and boron ion implantation at 150keV energy was conducted with dose of 10$\^$12/ and 10$\^$13/ions/cm$\^$2/. In ion implanted samples, the peaks related arsenic vacancy(V$\_$As/) were decreased but complex lattice defect was increased with annealing temperature. U band was observed at ion implanted(10$\^$13/ ions/cm$\^$2/) and thermally treated(550.deg. C) sample. More negative peak was detected after annealing at temperature between 600 and 700.deg. C. The measurement of dark current showed that the formation of B$\_$GA/-V$\_$As/, complex defect and complex lattice defect by ion implantation were a reasonable explanation for the decrease in dark current.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.469-472
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• 2000

a crack with electrically impermeable surfaces in an electrostrictive material subjected to uniform electric loading is analysed. A strip yield zone model is employed to investigate the effect of electric yielding on stress intensity factor. complete forms of electric fields and elastic fields for the crack are derived by using complex function theory. /the stress intensity factors are obtained based on the strip yield zone model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.62-63
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• 2016

In addition to the waterproof sheet waterproof objectives that apply to the building roof it is being constructed, including a complex such as insulation performance, root-resistance. However, thermal insulation of the composite waterproofing sheet is an insulating effect a wide variety depending on the specific construction -specific, material and even the effect is this part of the test to the generation when insignificant compared to each other a number of roof insulation effect of the insulation composite waterproof sheet that is currently in effect analysis.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.5
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• pp.174-182
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• 2020

The printed electronics field using ink-jet printing technology is in the spotlight as a next-generation technology, especially ink-jet 3D printing, which can simultaneously discharge and precisely control various ink materials, has been actively researched in recent years. In this study, complex structure of an insulating layer and a conductive layer was fabricated with photo-curable silica ink and PVP-added Cu nano ink using ink-jet 3D printing technology. A precise photocured silica insulating layer was designed by optimizing the printing conditions and the rheological properties of the ink, and the resistance of the insulating layer was 2.43 × 10¹³ Ω·cm. On the photo-cured silica insulating layer, a Cu conductive layer was printed by controlling droplet distance. The sintering of the PVP-added nano Cu ink was performed using an IPL flash sintering process, and electrical and mechanical properties were confirmed according to the annealing temperature and applied voltage. Finally, it was confirmed that the resistance of the PVP-added Cu conductive layer was very low as 29 μΩ·cm under 100℃ annealing temperature and 700 V of IPL applied voltage, and the adhesion to the photo-cured silica insulating layer was very good.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.357-361
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• 1999

GOD electrochemically immobilized in PPy/GOD complex have an effect on redox properties of the complex. In the cyclicvoltammetry, GOD shows the redox reaction at the potential below -0.6Y vs. Ag/AgCI. That leads to new peaks in the cyclicvoltammograms in additional to typical PPy peaks. The pH of electrolyte solution during potential swing decreased to 4.4, and then increased to 10. That suggests the redox of GOD for the cycling. As the concentration of GOD was increased, the anodic wave of the new peaks was strong as much as increased. GOD obstructs the diffusion of electrolyte anion because of its net chain. Insulating property of GOD is cause that it made the faradic impedance of complex large in charge transfer. It suggests that increase of the concentration of GOD be against electrochemical coupling. Therefore, the concentration of GOD and electrochemical coupling should be dealt with each other. The apparent Michaelis-lenten constant ( K\`$_{M}$ ) was determined by 30.7 mmol d $m^{-3}$ fur the PPy/GOD complex. The value is of the same order of magnitude as that for soluble glucose oxidase from Aspergillus Niger.r.