• Journal of the Korea Institute of Building Construction
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• v.21 no.5
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• pp.507-518
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• 2021

The application of an adhesive calcium carbonate-based hybrid insulation board with quasi-combustibility in the external thermal insulation composite system(ETICS) ensures effective thermal performance and fire safety. This study aimed to conduct a mechanical test of the quasi-non-combustible hybrid insulation board as well as its constituent materials to obtain the basic data for the structural design of the adhesive ETICS. Test specimens were fabricated based on domestic and foreign test standards to examine and evaluate their tensile, compressive, flexural, and shear strengths. The strength characteristics of the quasi-non-combustible hybrid insulation board were identified from the test results, which verified that the minimum required physical properties suggested by the current KS M ISO 4898 were met. Furthermore, the quasi-non-combustible ETICS used in this study was found to be suitable for use as an external insulation system for walls unless subjected to continuous gravity load, such as a heavy exterior finish.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.84-93
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• 2007

The pole transformer is one of the most important facility to insure the stability of electric power supply. which distributes electricity to customers directly. However there are a lot of defects which are caused by manufacturing fails(in 3 years) or deterioration (in 13 years), so we need a more improved transformer which insures quality. This thesis talks about the development of the new-type transformer using the hybrid insulation that is durable thermally, mechanically, and electrically. It would show how to lay out and produce the transformer using the hybrid insulation. And finally we are sure that we could increase the utilization rate of a transformer by 160% as compared with its own capacity through the overload test. Also, we carried out the examination about the short-circuit and insulation with a 100[kVA] model transformer, so that we expound the analysis of magnetic-mechanical forces intensity and the measure for improving short-circuit efficiency.

• Advanced Composite Materials
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• v.17 no.1
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• pp.25-40
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• 2008

The research and development in soundproof materials for preventing noise have attracted great attention due to their social impact. Noise insulation materials are especially important in the field of soundproofing. Since the insulation ability of most materials follows a mass rule, the heavy weight materials like concrete, lead and steel board are mainly used in the current noise insulation materials. To overcome some weak points in these materials, fiber reinforced composite materials with lightweight and other high performance characteristics are now being used. In this paper, innovative insulation sheet materials with carbon and/or glass fabrics and nano-silica hybrid PU resin are developed. The parameters related to sound performance, such as materials and fabric texture in base fabric, hybrid method of resin, size of silica particle and so on, are investigated. At the same time, the wave analysis code (PZFlex) is used to simulate some of experimental results. As a result, it is found that both bundle density and fabric texture in the base fabrics play an important role on the soundproof performance. Compared with the effect of base fabrics, the transmission loss in sheet materials increased more than 10 dB even though the thickness of the sample was only about 0.7 mm. The results show different values of transmission loss factor when the diameters of silica particles in coating materials changed. It is understood that the effect of the soundproof performance is different due to the change of hybrid method and the size of silica particles. Fillers occupying appropriate positions and with optimum size may achieve a better effect in soundproof performance. The effect of the particle content on the soundproof performance is confirmed, but there is a limit for the addition of the fillers. The optimization of silica content for the improvement of the sound insulation effect is important. It is observed that nano-particles will have better effect on the high soundproof performance. The sound insulation effect has been understood through a comparison between the experimental and analytical results. It is confirmed that the time-domain finite wave analysis (PZFlex) is effective for the prediction and design of soundproof performance materials. Both experimental and analytical results indicate that the developed materials have advantages in lightweight, flexibility, other mechanical properties and excellent soundproof performance.

• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.163-167
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• 2016

Inverter surge resistant enameled wire was prepared with an organic/inorganic hybrid nanocomposite, and the effect of ambient temperature on the insulation lifetime of the enameled wire in the form of twisted pair was studied by a withstanding voltage tester. The organic polymer was Polyesterimide-polyamideimide (EI/AI) and the inorganic material was a Nano-sized silica (average particle size : 15 nm). The enamel thickness was 50 μm and the ambient temperature was 100, 150, 200, and 250, respectively. Transmission electron microscopy (TEM) observation showed that Nano-sized Silica were evenly dispersed in EI/AI. There were many air gaps in a twisted pair, therefore, when voltage was applied to the twisted pair, enamel erosion took place in the air gap area because of partial discharge accordi, ng to Paschen’s law. As ambient temperature increased, insulation lifetime decreased according to Arrhenius relationship, which was explained by the increasing mobility of polymer chains in EI or AI. And insulation breakdown voltage value at 10 kHz was 1,864.5 sec (31.1 min), which is 1.9 times higher than at 20 kHz, 981.6 sec (16.4 min).

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.249-253
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• 2009

This paper dealt with the insulation evaluation by a measurement of partial discharge(PD) on traction motors used in a hybrid vehicle. The PD method has been accepted as an effective and a non-destructive. technique to evaluate insulation performance of low-voltage electric and electronic devices. In this paper, the PD measurement system which was manufactured with a coupling network, a low noise amplifier, and an associated electronics is described. The PD measurement system has the frequency bandwidth of $1[MHz]{\sim}30[MHz]$ at -3 [dB] and the stable sensitivity of 19 [mV/pC] for the traction motor. From the experimental results, discharge inception voltage (DIV) and apparent charge (q) were $1,100[V_{rms}]$ and 105 [pC] for the used motor, and $1,400[V_{rms}]$ and 84 [pC] for the new one. By comparing the DIV and q, we could evaluate the insulation condition for the traction motors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1721-1726
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• 2016

4-types of coils were prepared by coating with polyamideimide (PAI) organic/inorganic hybrid. One type was made with original PAI vanish and the other 3-types were made of double layers, that was to say, high flexural PAI layer and high anti-corona PAI/nanosilica (15 wt%) layer. Drying temperature (T/D) were $220^{\circ}C$, $240^{\circ}C$, and $260^{\circ}C$, respectively and rectangular type coil for high-voltage rotating machine was used. DC and AC electrical breakdown tests were carried out in order to study the insulation properties according to T/D temperature and coil curvature (5, 15, and $25mm{\Phi}$). As the curvature increased, electrical breakdown voltage decreased and as T/D temperature decreased, electrical breakdown voltage increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.133-134
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• 2019

As part of recent low-energy policies, thermal insulation standards for buildings are being tightened every year. The importance of external insulation methods is increasing due to the strengthening of insulation standards. Among the main materials used in the external insulation method, dry bit material is a finishing material composed of an organic binder and aggregate. When the fire occurs, the ignition of the surface part causes a direct fire on the thermal insulation material at the rear side when heat energy is concentrated. Therefore, it is important that the finishing material in dry insulation using a dry bit has a low fire spreading property in case of a fire and does not have a sustained combustion. The purpose of this study was to evaluate the fire spreadability by changing the internal fillers while using alkoxide-based acrylic emulsions, hybrid acrylic emulsions, and general acrylic emulsions in order to suppress the fire spreading properties of exterior finish materials.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.37-40
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• 2001

This paper describes a study for the development of light weight transformer with hybrid insulation system consists of A class insulation material and H class insulation material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.78-83
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• 2001

In this work, the surface of inorganic fillers were modified with some functional groups such as stearic acid, aliphatic long chain, vinylsilane and aminosilane to control the interaction between inorganic fillers and polymer matrix. Ethylene-vinyl acetate copolymers (EVA) with various amount of vinyl-acetate content and copolyether-ester elastomer were used as polymer matrix. The addition of inorganic fillers increases flame retardancy, but results in steep drop of electrical and mechanical properties, which may be caused by the defect in the interface between organic/inorganic hybrid composites. The hybrid composites are found to show better mechanical properties and higher volume resistivities as inorganic fillers are well dispersed and have good adhesion with polymer matrix. Also, the most effective type of functional group coated on fillers depends on the chemical structure of polymer.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.597-601
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• 2009

Green car such as a hybrid electrical vehicle and fuel cell vehicle is developed as a commercial target. UN/ECE/WP29 is developing GTR of HFCV and establishing the regulation and standard of electrical safety by ELSA. The regulation and standard about Electrical safety of vehicle are prescribed in ISO, UN/ECE, FMVSS, Japanese Attachment and so on, in case of insulation resistance is referred to keep more than 100/Vdc, 500/Vac. However, accurate method to measure insulation resistance agreeable to structure of vehicle does not exist now, it is actually that correctness of measurement drops according to the feature of battery and fuel cell stack. In this paper, the method to measure insulation resistance for protection against electrical shock by direct contact or indirect contact in Green Car will be indicated by making a comparison between the insulation measurement in standard of electrical safety and the experiment results for HEV and HFCV.