• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.05d
• /
• pp.38-42
• /
• 2003

The use of VPI impregnated mica tape as high voltage insulation for large rotating electric machines requires a careful balance of processes and materials to obtain the desired electrical, mechanical and thermal characteristics. The stator insulation systems such as epoxy bonded high voltage mica tape have been produced for many years. One such system employing an epoxy and anhydride impregnating resin developed by Hyundai Heavy Industries, Co. (hereafter, HHI), to satisfy customer requests for an epoxy bonded insulation system. HHI applies the following electrical and thermal evaluations such as dielectric breakdown, voltage endurance, dissipation factor vs. temperature, isothermal weight loss, and so on. A detailed laboratory evaluation can describe specific physical limitations for an insulation system and permit development of long-term operation guidelines that permit full utilization of the proposed system. HHI has found these evaluations very helpful in qualifying insulation system for the repair of both large motors and generators.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.10a
• /
• pp.1447-1448
• /
• 2004

As the plants are classified as a bulk facility by the Agency's safeguards criteria, the Material Balance Evaluation is a good tool to timely detect diversion that will be accomplished through the creation of defects as small as bias defects. Through all evaluations made by the Agency, it Is strongly recommended to report SRD based on both weight and enrichment, maintain the reliable MUF declaration and improve the gamma spectrometry measurement procedure. These recommendations have been now applied and are going on.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1994.05a
• /
• pp.50-56
• /
• 1994

Partial discharge on organic insulation surfaces are an important sauce of aging. Furthermore the modern PD measurement technigues are rapid developed as quality control and diagnostic tests to determine the fitness for use of HV equipment employing sol id electrical insulation. This paper deals with theory of conventional PD measurement and new tendency of technical development on PD measurements und evaluations. Finally the Measuring system used for diagnosing the surface aging on the organic insulation at High Voltage Laboratory of Technical University of Darmstadt in Germany is presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07a
• /
• pp.433-436
• /
• 2004

In this paper, we studied on the electrical safety evaluations of transformer insulation cover. In order to take preventive measures against an electric shock disaster in 22.9kV transformer installation, we put the insulation cover on a transformer charging parts. It needs to be designed so that the insulation covers have superior properties such as, arc-resistance, weather-resistance and heat-resistance, because they are used until the damage and destruction occur. To establish the protection cover to reduce the electrical shock, we analyzed damage mechanism and risk factors which happened by structural fault of an insulation cover in this paper. Also, based on the experimental results, we are planing to suggest new improved insulation cover models.

• Korean Journal of Logic
• /
• v.8 no.2
• /
• pp.85-107
• /
• 2005

Kleene first investigated a three-valued system which follows the evaluations of the Lukasiewicz infinite-valued logic ${\L}C$ with respect to negation, conjunction, and disjunction, and treats $\rightarrow$ as material-like implication in the sense that A $\rightarrow$ B is defined as ${\sim}A{\vee}B$ in its evaluation. Diense and Rescher extended it to many-valued logic and infinite-valued logic, respectively. This paper investigates a variant of the infinite-valued Kleene-Diense logic KD, which we shall call strong Kleene-Diense logic (sKD): sKD has the same evaluations as KD except that sKD takes a variant of Kleene-Diense implication. Following the idea of Dunn [2], we provide algebraic completeness for sKD together with its deduction theorem.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.829-834
• /
• 2002

Recently, research and development for a number of repairing material like an epoxy-based material and polymer-cementitious material as well as anti-washout underwater concrete have been carried out. But, the study on tile materials for the concrete structure exposed to a wetted condition is at a standstill and there are not any suitable reference data at a repairing work for the concrete structure at a splash as well as a structure under severe moisture condition. In this study, the material, called as “ceramic metal”, with an excellent mobility and plasticity as well as with a high bond strength and durability of freezing-thawing resistant properties under any environmental conditions was developed. And, the experimental evaluations for the utility wert widely performed.

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3581-3590
• /
• 2023

High-temperature design evaluations were conducted on Type 316L stainless steel piping for a 700 ℃ large-capacity thermal energy storage verification test loop (TESET) under construction at KAERI. The hot leg piping with sodium coolant at 700 ℃ connects the main components of the loop heater, hot storage tank, and air-to-sodium heat exchanger. Currently, the design rules of ASME B31.1 and RCC-MRx provide design procedures for high-temperature piping in the creep range for Type 316L stainless steel. However, the design material properties around 700 ℃ are not available in those rules. Therefore, a number of material tests, including creep tests at various temperatures, were conducted to determine the insufficient material properties and relevant design coefficients so that high-temperature design on the 700 ℃ piping may be possible. It was shown that Type 316L stainless steel can be used in a 700 ℃ high-temperature piping system of Generation IV reactor systems or a renewable energy systems, such as thermal energy storage systems, for a limited operation time.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.1101-1104
• /
• 2001

The special purposed materials, such as ceramics and stainless steel, are widely used in the various industrial area. They have properties of the higher strength of material, the wear-resistance, and the corrosion proof. But ceramics is a difficult-to-grind material which possesses the higher level of a strength and a brittleness. In this study, the theoretical investigation of a grinding force and of a surface roughness was conducted. The evaluations of grinding characteristics on the hardened-brittle and difficult-to-grind materials were experimentally carried out.

• Journal of the Korean Ceramic Society
• /
• v.36 no.6
• /
• pp.571-576
• /
• 1999

This paper describes both electromagnetic properties and electromagnetic-wave absorbind (EMA) characteristics of the radar absorbing coating materials in the microwave frequencies. The coating materials are prepared by mixing ferrite powder with epoxy resin polymers. The electromagnetic property and the EMA characteristics of the coating materials are measured in the frequency ranges between 0.2 GHz and 15GHz using the S-parameter method. The results show that the typical coating material has ({{{{ {μ }`_{r } ^{' } }} of about 2 and ({{{{ { ε}`_{r } ^{' } }} of about 4. And the coating materials have a little EMA characteristics in the frequency from 4 to 6 GHz and more improved EMA characteristics around 12 GHz And it is desirable for improvement of the EMA characteristics of the coating materials to properly select electromagnetic properties of constitutional materials inthe interesting frequency ranges.

• The Journal of the Korean dental association
• /
• v.49 no.3
• /
• pp.159-169
• /
• 2011

The author have been conducting research on the development of biomaterials using human teeth since 1993, and we recently reported the results of several of our advanced studies. Based on previous studies, new bone graft material using autogenous tooth(AutoBT) was developed. The author performed implant placement combined with GBR and sinus bone graft using AutoBT during the period of June 2009 to September 2009. During the postsurgical healing period, clinical and radiological evaluations were performed. For patients who consented to histological testing, tissue samples were obtained and histological examination was performed two months and four months after GBR and four months after sinus bone graft. Serious complications pertinent to bone graft materials were not observed, and it was shown that the level of the crestal bone in the vicinity of implants was relatively well maintained. In histologic examination after two months and four months, favorable new bone formation was observed.