• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.4
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• pp.238-243
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• 2015

The vegetable insulating oils are substitute for the mineral oil in power transformer. Vegetable insulating oils has higher flash/fire point and biodegradability than conventional mineral oils. In this paper, we investigated the dissolved gas analysis of vegetable oils. In the experiment, I had to accelerated aging under the same conditions mineral oil and vegetable oils. Accelerated aging proceeded to about 100% of the life of oil-filled transformer. In addition, we performed gas analysis of insulating oil of accelerated aging progress. The experiment results of the five gases was measured with the exception of Hydrogen and Acetylene. The mineral oil and vegetable oils gas is generated in a similar tendency depending on the accelerated aging. As a result, vegetable oils, can be dissolved gas analysis by method such as mineral oil.

• Journal of the Korean institute of surface engineering
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• v.35 no.2
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• pp.113-121
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• 2002

We have investigated insulating properties of $SiO_2$ interlayer for the thin film strain gauge, which were prepared by RF magnetron sputtering method in various deposition conditions, such as Ar pressure, gas flow rates and sputtering gases. SEM, AFM and FT-IR techniques were used to analyze its structures and composition. As the Ar pressure and the flow rate increased, the insulating interlayer showed low insulating resistance due to its porous structure and defects. Oxygen deficiency in $SiO_2$ was decreased as fabricated by hydrogen reactive sputtering. We could enhance the surface mobility of sputtered adatoms by using Ar/$H_2$ sputtering gas and obtain a good surface roughness and insulating property. The optimum insulating resistance of 9.22 G$\Omega$ was obtained in Ar/30% $H_2$ mixed gas, flow rate 10sccm, and 1mTorr.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.388-389
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• 2007

Objective of the study is development of 23kV insulating jackets for protection of workers from electrical shock. The breakdown voltage of Ethylene-VinylAcetate copolymers(EVA) films in insulating oil were measured. Insulating jackets were made by the high frequency welding machine, and withstanding voltage test of these were measured. For breakdown voltage at AC 30kV, the number of EVA film with $105{\pm}5{\mu}m$ thickness was 4$\sim$5pieces. When AC 30kV during 3 minutes supplied on the insulating jackets, those were keep on the good quality.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.449-452
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• 2004

The life of power transformer is basically dependent on the aging deterioration of insulating paper. Analysis of insulating paper for its DP value or tensile strength requires removal of a few strips of paper but direct measurement of this properties is not practical for in-service transformers. For this reason furfural analysis by HPLC has gained increasing favor as a means of estimating degradation of insulating papers in power transformers and this paper reports on the analysis of data on the concentration of furfural in oil samples from about 50 power transformers and the case study. The data showed that furfural content can estimate more accurately aging characteristics compared to concentration of CO, $CO_2$. We expect that these results can be useful to predict the aging characteristics and life diagnosis of power transformers and further the study must be continued.

• Textile Coloration and Finishing
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• v.35 no.4
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• pp.274-283
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• 2023

Conductive polymers are polymers that conduct electricity like metal conductors. Unlike typical organic polymers, they are polymers that have the electrical, magnetic, and optical properties of metals or semiconductors. For Example, these conductive polymers include Polypyrrole (PPy), Polyaniline (PANI), and Polythiophene (PT). On the other hand, Insulating polymers do not conduct electricity well while providing insulation, which is the opposite of conductivity. With the exception of conductive polymers, most polymers are non-conductors. Insulating polymers include polyimide (PI), polystyrene (PS), and poly(vinyl alcohol) (PVOH, PVA, or PVAl). Although many different polymers exist, we have simply illustrated the properties and recent developments of conductive and insulating polymers, which have opposite properties.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.642-649
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• 2021

Energy saving standard for buildings are strengthened, the application of exterior insulation finishing system and thickness of insulation materials are increasing. Most buildings with exterior insulation finishing system is applied organic insulating material. Organic insulating material have workability, economic feasibility, reduction in construction cost, and excellent thermal insulation performance. However, Organic insulating material is very vulnerable to heat, so when a fire occurs, rapid fire spread and toxic gas are generated, causing many casualties. Inorganic insulating material can be non-combustible performance, but it is heavy and has low thermal insulation performance. Mineral wool has higher thermal insulation performance than other types of inorganic insulating material, but mineral wool is disadvantageous to workability and vulnerable to moisture. Glass bubble are highly resistant to water and chemically stable substances. In addition, the density of the glass bubble is very low and the particles are spherical, fluidity is improved by the ball bearing effect. Glass bubbles can be used with cement-based ino rganic insulating material to impro ve the weight and thermal insulatio n perfo rmance o f cement-based inorganic insulation. This study produced a inorganic insulating materials were manufactured using cement-based materials and glass bubble. In order to evaluate the insulation performance and flame retardant performance of cement-based super light-weight inorganic insulating materials using with glass bubble, insulation performance or flame retardant and non-combustible performance were evaluated after manufacturing insulating materials using micro cement and two types of glass bubbles. From the test result, Increasing the mixing ratio of glass bubbles improved the insulation performance of cement-based super light-weight inorganic insulating materials, and when the mixing ratio of glass bubbles was 10%, it sho wed sufficient flame retardant and no n-co mbustible perfo rmance.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.1-7
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• 2006

A major failure mode for wafer level chip size package (WLCSP) is thermo-mechanical fatigue of solder joints. The mechanical strains and stresses generated by the coefficient of thermal expansion (CTE) mismatch between the die and printed circuit board (PCB) are usually the driving force for fatigue crack initiation and propagation to failure. In a WLCSP process peripheral or central bond pads from the die are redistributed into an area away using an insulating polymer layer and a redistribution metal layer, and the insulating polymer layer affects solder joints reliability by absorption of stresses generated by CTE mismatch. In this study, several insulating polymer materials were applied to WLCSP to investigate the effect of insulating material. It was found that the effect of property of insulating material on WLCSP reliability was altered with a solder ball layout of package.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.332-335
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• 2012

A molded transformer is maintenance-free, which makes it unnecessary to replace the insulating material, like in an oil-filled transformer, because the epoxy, which is a molded insulating resin, does not suffer variations in its insulating performance for heat cycles over a long time, as compared to insulating oil. In spite of these advantages, a molded transformer may still be accessed by the user, which is not good in regards to reliability or noise compared to the oil transformers. In particular, a distrust exists regarding reliability due to the long-term insulating performance. These properties have been studied in regards to the improvement of epoxy composites and molded transformer insulation. There have nevertheless been insufficient investigations into the insulation properties of epoxy composites. In this study, it is a researching of the epoxy for insulating material. In order to prepare the specimens, a main resin, a hardener, an accelerator, and a nano/micro filler were used. Varying amounts of TiO2 and ZnO nano fillers were added to the epoxy mixture along with a fixed amount of micro silica. This paper presents the DC insulation breakdown test, thermal expansion coefficient, and thermal conductivity results for the manufactured specimens. From these results, it has been found that the insulating performance of nano/micro epoxy composites is improved as compared to plain molded transformer insulation, and that nano/micro epoxy composites contribute to the reliability and compactness of molded transformers.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1235-1238
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• 1995

Electrical property of polymeric insulating plays a key role in the trend of making power apparatus high voltage, and reliability and safety of apparatus in the long term depend on it. There is a recent trend of applying polymeric material to insulating material for outdoor, and particularly it is expected that it may be used partly as a pin insulator. Using as an alternate of insulating material for outdoor, however, it has still many problems to be solved in the field of material such as resistances of environment and tracking. It has been given attention to that the silicon rubbers and the epoxy have recently been used. but the the reliability in the viewpoint of material property becomes an issue. The polymeric materials such as EPDM, Epoxy and PVC have also been used as an insulating materials for outdoor. In this point of view, we studied each tracking phenomenon with test material such as rubber for pin, PVC for powercable used as an insulating material for outdoor, and Epoxy etc. The characteristics of anti tracking shows EPDM>Epoxy>PVC in order in the results. We also know that there is an close relationship between properties of tracking and thermegravimetry.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.357-360
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• 2006

In this study, we studied the physical properties and application of PF foam as heat insulating materials. In the experimental results, the density of PF foam showed $0.030g/cm^3$ and the thermal conductivity showed $0.026kcal/m.h.^{\circ}C$. Also, thermal resistance of the prepared PF foam was volatilized about 71.7 wt% when the temperature was $500^{\circ}C$ (1 h). And the chemical structure of PF foam have a closed cell type in the important properties as heat insulating materials. Therefore, it was confirmed that the prepared PF foam had excellent performance as heat insulating materials.