• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1391-1393
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• 2008

In this paper, the long-term reliability for 1.25G transceiver in use of high speed optical access network is investigated. High temperature storage tests and accelerated life tests are used to long-term reliability. Accelerated aging test have been during 3,000 hour of the three accelerated aging conditions by caused high temperature stress. Mean life is assumed to follow the Arrhenius relationship and analysis from the failure data obtained in the accelerated aging conditions.

• 한국압력기기공학회 논문집
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• 제12권1호
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• pp.41-48
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• 2016

To investigate the effect of long-term thermal aging on the microstructural and mechanical characteristics of weldment made of nickel base alloy and its weld metal, an accelerated heat treatment was applied to simulate the process of long-term thermal aging in the operating condition of nuclear power plant. A representative nickel-based weldment with Alloy 600 and Alloy 182 was fabricated and heat-treated at $400^{\circ}C$ for 1,713 h and 3,427 h to simulate the thermal aging for the period equivalent to 15 and 30 years in operating pressurized water reactors, respectively. The microstructural and mechanical characteristics were analyzed by using optical microscopy, scanning electron microscopy and Vickers microhardness measurement. Changes were observed in precipitation behavior and microhardness of each specimen, and these changes were mainly attributed to the change in precipitated morphology and residual stress across the weld during the thermal aging process.

• 한국기계가공학회지
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• 제21권1호
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• pp.56-65
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• 2022

The electrochemical corrosion properties of austenitic AISI 304 steel subjected to a long-term-aging heat treatment were investigated. AISI 304 steel was aged at 700 ℃ for up to 10,000 h. The variation in the microstructure of the aged specimens was observed by optical microscopy and scanning electron microscopy. Electrochemical polarization experiments were performed to obtain the corrosion current density (Icorr) and corrosion potential (Ecorr). Analyses indicated that the metastable intermetallic carbide M₂₃C₆ formed near the γ/γ grain boundary and coarsened with increasing aging time; meanwhile, the δ-ferrite decomposed into the σ phase and into M₂₃C₆ carbide. As the aging time increased, the current density increased, but the corrosion potential of the austenitic specimen remained high (at least 0.04 ㎛/cm²). Because intergranular carbide was absent, the austenitic annealed specimen exhibited the highest pitting resistance. Consequently, the corrosion resistance of austenitic AISI 304 steel decreased as the aging heat treatment time increased.

• 대한물리치료과학회지
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• 제7권2호
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• pp.397-405
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• 2000

Recently, the problem of the elderly has become national and social issue throughout the world. And the ratio of elderly increase is expected to get accelerated more and more year after year. But the long-term care policy for the elderly in korea has not developed systematically yet. Therefore, in this study aims at searching the method for developing the long-term care policy of korea and the role of physical therapist for long-term care.

• 한국노년학
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• 제41권1호
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• pp.85-105
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• 2021

본 연구는 활동적 노화의 관점을 적용하여 장기요양시설에서의 돌봄 유형에 관한 다양한 인식유형을 분석하는 데 목적을 둔다. 이를 위해 Q방법론을 적용하였다. WHO의 활동적 노화를 위한 건강, 안전, 참여 세 영역에서 장기요양시설의 돌봄에 관한 다양한 생각을 파악하기 위해 심층면접을 진행하였다. 면접조사에는 장기요양시설 거주 노인, 거주 노인의 성인자녀, 지역사회 거주 노인, 서비스 제공자, 장기요양 전문가 등 35명이 참여하였다. 451개의 Q모집단 중 63개의 Q표본을 추출하였으며, 최종 자료분석에는 43개의 P표본 자료가 활용되었다. QUANL 프로그램을 활용하여 자료를 분석한 결과, 3개의 요인구조(4개 유형)가 적합하며 이는 전체 변량의 30.15%를 설명하는 것으로 나타났다. 현재 장기요양시설의 돌봄은 보호 중심 돌봄(1유형), 참여 중심 돌봄(2유형), 의료연계 중심 돌봄(3유형), 인간 중심 돌봄(4유형)으로 유형화할 수 있다. 본 연구결과를 바탕으로 장기요양시설에서 돌봄의 질적 변화를 위한 제도적, 실천적 함의를 제시하였다.

• 보건행정학회지
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• 제32권3호
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• pp.258-271
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• 2022

The rapidly aging trend of Korea is a major factor that threatens the sustainability of the long-term care insurance system. Therefore, looking at how Japan and Germany mitigated the financial burden when they managed similar long-term care insurance systems will provide important implications for improving the Korean system in the future. The study was conducted using the literature review method, and the "country" was set as a unit for the case analysis. The three countries selected are Korea, Japan, and Germany. Recently in Korea, the insurance premium rates of all subjects have been rapidly rising, which can exacerbate the issue of intergenerational equity. On the other hand, Japan has responded to the aggravating finances for long-term care insurance due to aging by raising coinsurance for selected groups like the wealthy elderly. Germany is selectively raising the insurance premium rates by additionally increasing the premium rate for childless recipients. A more preventive and quality-oriented care service plan can be promoted by referring to the recent changes in Japan and Germany. In addition, a more effective and selective increase in payment burden in Japan and Germany could be considered in response to a recent equity issue in Korea.

• 한국병원경영학회지
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• 제20권4호
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• pp.50-61
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• 2015

Advances in healthcare technology and rapid economic growth lead to the increased life expectancy and consequently the size of elderly population. Korea is one of the countries that are rapidly aging. Thus, it is particularly important to prepare for the aging society. Recently, the number of healthcare institutions for the elderly citizens has increased. The purpose of selecting a hospital for the elderly is, in general, maintenance of health rather than improvement of health receiving proper treatment. Unlike choosing a hospital for treatment, customers of a long term care hospital have a different set of factors to consider. Especially, when choosing a long term care hospital, the influence of patient's family is greater than the patient. This study examines the factors they consider for long term care hospital. A total of 198 questionnaires were collected from the families of actual patients of long term care hospitals. Twelve questionnaires were found to be non-usable because of missing and unsatisfactory responses. Consequently, 186 questionnaires were used for the analyses. Findings of this study are as follows. First, seven factors have been identified to consider when choosing a long term care hospital for the elderly. They include convenience of facilities, costs variety of facility programs, service hours, reputation, accessibility, quality of medical staff, medical facilities, and facility size. Second, This study measured both importance and satisfaction with these attributes and analyzed the difference between them. Satisfaction was lower than importance in the categories of convenience of facilities, costs, and programs, and accessibility. On the other hand, satisfaction was higher in terms of service hours, reputation, and quality of medical staff. Finally, the current study found positive impact of accessibility and quality of medical staff on reuse intention of a long term care hospital.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.709-731
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• 2022

Loss of fracture resistance due to thermal aging degradation is a potential limiting factor affecting the long-term (80+ year) viability of nuclear reactors. To evaluate the effects of decades of aging in a practical time frame, accelerated aging must be employed prior to mechanical characterization. In this study, a variety of chemically and microstructurally diverse austenitic stainless steels were aged between 0 and 30,000 h at 290-400 ℃ to simulate 0-80+ years of operation. Over 600 static fracture tests were carried out between room temperature and 400 ℃. The results presented include selected J-R curves of each material as well as K_0.2mm fracture toughness values mapped against aging condition and ferrite content in order to display any trends related to those variables. Results regarding differences in processing, optimal ferrite content under light aging, and the relationship between test temperature and Mo content were observed. Overall, it was found that both the ferrite volume fraction and molybdenum content had significant effects on thermal degradation susceptibility. It was determined that materials with >25 vol% ferrite are unlikely to be viable for 80 years, particularly if they have high Mo contents (>2 wt%), while materials less than 15 vol% ferrite are viable regardless of Mo content.

• 한국식품영양학회지
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• 제32권4호
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• pp.349-354
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• 2019

In this study, 30 kinds of long-term and mature Korean soy sauce were collected and classified by the fermentation period, and the components related to taste and sensory characteristics were analyzed. A total of 4 kinds of organic acids were detected. The total organic acid content was in the range of 97.2~341.6 mg%, but did not show the tendency to increase or decrease in proportion to the aging period. The total free amino acid content was within the range of 3,001.0~3,834.7 mg% and showed a tendency to increase in proportion to the ripening period of the soy sauce. The contents of aspartic acid and glutamic acid subsequently increased in the long-term matured soy sauce. The ratio of essential amino acid to total amino acid was 31.6~35.7%, and the ratio of glutamic acid to total amino acid was 19.6~23.9%, respectively. The panel of 20~29-year-old indicated that the longer the aging period of soy sauce, the lower the preference while the panel of 30 or more years indicated that the longer the aging period of soy sauce, the higher the preference. This study was the first to investigate the quality of long-term matured soy sauce in more than one year.

• 한국지진공학회논문집
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• 제17권3호
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• pp.117-125
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• 2013

Seismic isolation has been considered and utilized in various industries as a way to prevent huge damage on to structures by large earthquakes in various industries. The laminated Laminated rubber bearings is are most frequently used in seismic isolation systems. The structural Structural safety could not be assured unless the performance of the rubber bearing is not guaranteed for the life time of the structure under the consideration that the bearing is a critical structural member to sustain vertical loads in the seismically isolated structure. However, there are few studies on the deterioration problems of rubber bearings during their service life. The long term performance of the rubber bearings was not considered in past designs of seismically isolated structures. This study evaluates the long term performance and creep characteristics of laminated natural rubber bearings that are used in seismically isolated buildings. For the this study, a set of accelerated thermal aging tests and creep tests are were performed on real specimens. The experimental results show that the natural rubber bearings would have a stable change rate of change for durability under severe environmental conditions for a long time.