• 대한기계학회논문집A
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• 제28권4호
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• pp.460-466
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• 2004

Cast austenitic stainless steel is used for several components, such as primary coolant piping, elbow, pump casing and valve bodies in light water reactors. These components are subject to thermal aging at the reactor operating temperature. Thermal aging results in spinodal decomposition of the delta-ferrite leading to increased strength and decreased toughness. This study shows that ferrite content can be predicted by use of the artificial neural network. The neural network has trained teaming data of chemical components and ferrite contents using backpropagation learning process. The predicted results of the ferrite content using trained neural network are in good agreement with experimental ones.

• 열처리공학회지
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• 제14권6호
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• pp.323-329
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• 2001

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. The carbide morphologies were classified as acicular, pipe and globular type, and the number of carbides per unit area was measured for each type of carbides. The fine acicular carbides were found to diminish drastically in the initial stage of aging. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the magnetic property measurements such as saturation magnetization, coercivity and remanence. The saturation magnetization showed no distinct trend with aging time. However, the coercivity and remanence were observed to decrease rapidly in initial 920 hours of aging time and then decrease slowly afterwards.

• The Journal of Advanced Prosthodontics
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• 제8권1호
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• pp.30-36
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• 2016

PURPOSE. The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. MATERIALS AND METHODS. An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling $5^{\circ}C-55^{\circ}C$ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at $137^{\circ}C$, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. RESULTS. The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. CONCLUSION. The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns.

• 한국인공지능학회지
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• 제9권2호
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• pp.15-21
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• 2021

This paper conducted a feasibility study by applying an Internet of Things and Artificial intelligence-based management system for the elderly living alone in an aging society. The number of single-person families over the age of 50 is expected to increase, and problems such as health, safety, and loneliness may occur due to aging. Therefore, by establishing an IoT-based care system for the elderly living alone, a stable service was developed through securing a rapid response system for the elderly living alone and automatically reporting 119. The participants of the demonstration test were subjects under the jurisdiction of the "Seongnam Senior Complex," and the data collection rate between the IoT sensor and the emergency safety gateway was high. During the demonstration period, as a result of evaluating the satisfaction of the IoT-based care system for the elderly living alone, 90 points were achieved. We are currently in the COVID-19 situation. Therefore, the number of elderly living alone is continuously increasing, and the number of people who cannot benefit from care services will continue to occur. Also, even if the COVID-19 situation is over, the epidemic will happen again. So the care system is essential. The elderly care system developed in this way will provide safety management services based on artificial intelligence-based activity pattern analysis, improving the quality of in-house safety services.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.119-122
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• 2000

Recently polymer insulators are being used for outdoor high voltage applications. Polymer insulators for transmission line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. Polymer insulators are a relatively new technology, but their expected life is still unknown. Therefore these estimating technique are very important. Their life time is related to weathering and operating condition. Multi-aging test is requested because aging factor is occurred by multi-aging than unique aging. The aging test about polymer insulators have mainly carried out by IEC 61109. This paper presents multi-stress chamber experiments and tracking wheel test to examine the tracking and erosion performance of polymer insulator for transmission. Multi-stress testing is able to demonstrate deficiencies of polymer insulator materials and designs, including the nature of interfaces in insulation design. We have investigated IEC 61109 Annex C (5000h aging test) and CEA tracking wheel test as test methods of artificial accelerated aging. The aging degree of polymer insulator is estimated by leakage current, measurement of hydrophobicity degree, damage conditions of insulator surface, withstand voltage test etc.

• 대한화장품학회지
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• 제30권4호
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• pp.463-470
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• 2004

인공피부배양물(DA-3711)은 동아제약의 인공피부배양기술을 활용하여 개발되었으며, 노화된 피부상태를 개선시켜 줄 수 있는 천연의 세포외기질 단백질을 비롯하여 인체성장인자 등의 영양성분을 함유하고 있다 DA-3711의 항노화 효과는 in vitro와 in vivo에서 규명되었으며, 또한 인체 효능 연구 결과에서도 피부탄력을 개선시키고 주름을 감소시키는데 매우 효과적이었다. 즉, DA-3711을 이용한 새로운 주름개선제는 피부재생을 촉진시켜 항노화 및 주름개선 효능을 나타낸다.

• 융합정보논문지
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• 제11권2호
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• pp.16-24
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• 2021

본 논문은 고령화 사회로 진입함에 따라 급속히 늘어나는 고령자를 위하여, IoT와 인공지능 기술을 적극 활용하여 고령자로 하여금 행복한 노년을 영위할 수 있도록 도와주는 smart aging 서비스를 소개한다. 특히 고령화문제를 해결하려는 기존의 복지개념에서 탈피하여 긴급 상황에서 자신을 보호하고 감성을 만족시키어 활기찬 고령사회 구축으로의 패러다임 변화를 이끌어내는, 미래지향의 고령 친화적 wellbeing 지원 시스템을 제안한다. IoT(사물인터넷)와 AI(인공지능)를 도입하여 고령자의 생활정보로부터 생활상황 및 감성상태를 판단하여 긴급 상황 대응, 기분전환과 감성 위로 제공 및 모임을 추천한다. 제안 시스템은 맥박, 위험한 단어사용 및 외부소통 등의 정보를 입력하면 인공지능 기법을 이용하여 우울증의 정도를 판단해줌으로써, 기존 헬스케어 중심의 복지개념에서 탈피하여 고령자에게 감정적인 행복감을 제공하는 새로운 개념의 wellbeing 지원 시스템의 실현가능성을 보여주었다고 생각한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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• pp.93-96
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• 2007

In this paper, the testing equipment for evaluating aging characteristics of outdoor silicone rubber insulator resulting from the environmental aging effect with regards to sunlight(UV) was developed. Influence of sunlight effect aging is seriously increase due to destruction of ozone layer which is occurred by consumption of fossil fuel. For this purpose, silicone rubber was aged under the artificial sunlight by exposure of xenon lamp radiation in the accelerating aging chamber and various test and analysis were performed such as breakdown strength, contact angle. And FT-IR analysis has been followed.

• 펄프종이기술
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• 제40권2호
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• pp.43-56
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• 2008

The purpose of the experiment was to evaluate the material stability of the paper of the annals of Joseon Dynasty for the conservation purpose and the categories were as listed below : 1. Procuring traditional Hanji and semi-Hanji from different regional hanji paper mill. 2. Artificial accelerated aging treatment to examination its stability (UV irradiation, dry heat) 3. Analysis of optical, physical characteristic. The suitable Hanji for categories would be used as a reconstruction material for the waxel paper in the papers of the annals of Joseon Dynasty.

• 대한금속재료학회지
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• 제49권1호
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• pp.9-16
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• 2011

To develop a 6061 aluminum alloy with low residual stress and high tensile strength, a cryogenic treatment process was investigated. Compared to the conventional heat treatment process for precipitation hardening with artificial aging, the cryogenic treatment process has two additional steps. The first step is cryogenic quenching of the sample into liquid nitrogen, the second step is up-hill quenching of the sample into boiling water. The residual stress for the sample was measured by the $sin^2{\psi}$ method with X-ray diffraction. The 6061 aluminum alloy sample showed 67% relief in stress at the cryogenic treatment process with artificial aging at $175^{\circ}C$. From this study, it was found that the optimum cryogenic treatment process for a sample with low residual stress and high tensile strength is relatively low cooling speed in the cryogenic quenching step and a very high heating speed in the up-hill quenching step.