• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1177-1182
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• 2003

The porous sensing materials for BaTiO$_3$ gas sensors were fabricated by adding the graphite powders. The crystalline structure and microstructure of the porous BaTiO$_3$-based ceramics were studied. All the sintered bodies showed a tetragonal perovskite structure. The porosity increased with increasing graphite contents. This is mainly due to an enhanced evolution of CO and $CO_2$ gases resulting from the exothermic reactions of graphite and oxygen during the sintering. It was found that the discrepancy in the resistivities measured in air and CO atmospheres at high temperatures (>∼20$0^{\circ}C$) became remarkable with increasing temperature. The sensitivity of CO gas increased with porosity, since the reactions between CO gas and $O_2$$^{[-10]}$ and between CO gas and $O^{[-10]}$ are active due to the formation of many reaction sites. The porous BaTiO$_3$-based ceramics could be promising as a sensing material for CO gas sensors.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.154-157
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• 2013

We report an unusual case of ectopic pancreas that appeared on radiologic images as a lobulated, submucosal mass enclosed by fat component in the gastric lower body. Although, ectopic pancreas including fat component is extremely rare, in the setting of gastric submucosal mass with containing perilesional fat, these findings should be considered in ectopic pancreas as part of the differential diagnosis.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.25-35
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• 1999

LTCC (Low Temperature Cofired Ceramic) or LTCC-M (Low Temperature Cofired ceramic on Metal) technology is one of MCM-C (Multichip Module on Ceramic) technologies and becomes to be widely used in consumer, RF and automotive electronics. As green sheets for LTCC are cofired below $1000^{\circ}C$ in comparison with those for HTCC (High Temperature Cofired Ceramic), high conductivity metal traces such as gold, silver and copper can be used. The dimensional stability in LTCC-M technology enables embedded passives to be integrated inside modules, which enhances the electrical performance and increases the reliability of the modules. Coefficient of thermal expansion and dielectric constant can be controlled by changing composition and heating profile for cofiring. In this technical review, LTCC and LTCC-M technologies are introduced and advantages of those technologies are explained.

• Journal of Energy Engineering
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• v.28 no.2
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• pp.55-62
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• 2019

The purpose of this research is to find the optimum combustion conditions for the celadon using a gas kiln. It is clearly defined by the amount of CO gas in the kiln that it is fired in the commonly used oxidation and reduction atmosphere. As a result, while celadon was fired at $1250^{\circ}C$, oxidation happened when the amount of CO was 0~4,500 PPM, a neutral condition happened when the of CO was 4,500~25,000PPM and a reducing process was happened when the of CO was more that 25,000PPM. To reduce gas and firing time while keeping uniformly the firing temperature and firing condition of the gas kiln, you can partially block the gas corridor and adjust it as a damper. This adjustment reduces gas consumption by 40% and shortens the firing time by 1 hour.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.753-764
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• 2020

In this study, the plastic zone and internal earth pressure of the tunnel were calculated using the following three methods: metal plasticity to analyze the deformation of metal during plastic processing, Terzaghi's earth pressure theory from the geotechnical perspective and modified Terzaghi's earth pressure theory, and slip line theory using Mohr-Coulomb yield conditions. All three methods are two-dimensional mathematical analysis models for analyzing the plane strain conditions of isotropic materials. Using the theory of metallurgical plastics, the plastic zone and the internal earth pressure of the ground were obtained by assuming that the internal pressure acts on the tunnel, so different results were derived that did not match the actual tunnel site, where only gravity was applied. An analysis of the plasticity zone and earth pressure via the slip-line method showed that a failure line is formed in a log-spiral, which was found to be similar to the real failure line by comparing the results of previous studies. The earth pressure was calculated using a theoretical method. Terzaghi's earth pressure was calculated to be larger than the earth pressure considering the dilatancy effect.

• The Journal of the Korean bone and joint tumor society
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• v.19 no.2
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• pp.92-96
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• 2013

Heterotopic ossification is an abnormal bone formation after surgery or without any reason. Large joint, such as hip and knee joint, is a known most common site. Operation itself and postoperative early range of motion exercise are risk factors. We present a case of heterotopic ossification mimics neurogenic tumor after high tibial osteotomy.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.537-539
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• 2009

A 47-year old woman was admitted to our hospital for removal of a known mass that was located on the suprasternal notch; specifically, the mass was located on the supero-anterior mediastinuum. The mass was removed by a cervical incision and the histopathologic diagnosis of the resected specimen was hererotopic thyroid tissue with nodular hyperplasia. Mediastinal hererotopic thyroid tissue is a rare malady, so we report here diastinal hererotopic thyroid tissue and we review the relevant medical literature.

• Journal of the KSME
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• v.29 no.3
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• pp.270-278
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• 1989

최근 탄소성체의 소성불안정 현상과 소성 변형집중화에 의한 연성파괴 거동의 해석에 유력한 수단으로 인식되고 있는 대변형 탄소성유한 요소법의 정식화에 대하여 소개하였다. 또한 이 유한요소법에 의한 각종 소성불안정 현상의 해석에 있어서 구성관계식의 선택은 매우 중요한 의미를 갖고 있어 자주 이용되고 있는 대표적인 구성식의 특성에 대해서 논하였다.

• Journal of the KSME
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• v.57 no.6
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• pp.42-46
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• 2017

이 글에서는 거시소재와 나노소재의 소성 거동이 상이한 이유에 대해 간략히 논하고, 전산역학을 이용한 금속나노소재의 소성 변형 메커니즘 연구를 면심입방 소재의 예를 통해 소개하고자 한다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.40-45
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• 2002

일반적으로 마모 손상된 원자력 발전소의 증기발생기의 전열관은 소성변형의 불안정에 의하여 파열이 발생된다. 이에 본 연구예서는 증기발생기 전열관에 평면형(flat type), 원주형(circumferential type)의 마모가 존재한다고 가정하고 소성 불안정(plastic instability) 해석에 기초하여 파열압력을 구하였다 또한 실험 결과와 비교하여 본 연구 해석 결과와 잘 일치함을 보였다.(중략)