• 펄프종이기술
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• 제46권6호
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• pp.87-93
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• 2014

Optical brightening agents (OBA) is generally used to improve the optical property of printing paper in the paper industry. However, effects of OBA addition on paper preservability has been not fully understood yet. Therefore, this study was aimed to investigate effects of a OBA on the aging characteristics of paper. The OBA treatment of three different types was performed by dipping a filter paper into each a OBA solutions of different concentrations. The filter papers applied with a OBA were artificially aged at 80oC and 65% RH, and their optical and mechanical properties were evaluated. It was found that application of OBAs influenced the aging characteristics of paper. Especially, after aging, the optical and mechanical properties of the filter paper treated with the tetra-type OBA were more significantly decreased than those of the non-treated filter paper. The more the concentration of the tetra-type OBA increased, the more decreasing rate of optical and mechanical properties of the filter paper. While, in case of di-type OBA and hexa-type OBA, paper optical and mechanical properties were slightly decreased or not changed with a OBA treatment.

• 통합자연과학논문집
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• 제16권2호
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• pp.61-67
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• 2023

Human body ages differently due to environmental, genetic and pathological factors. DNA methylation patterns also differs depending on various factors such as aging and several other diseases. The aging clock model, which uses these differences to predict age, analyzes DNA methylation patterns, recognizes age-specific patterns, predicts age, and grasps the speed and degree of aging. Aging occurs in everyone and causes various problems such as deterioration of physical ability and complications. Alzheimer's disease is a disease associated with aging and the most common brain degenerative disease. This disease causes various cognitive functions disabilities such as dementia and impaired judgment to motor functions, making daily life impossible. It has been reported that the incidence and progression of this disease increase with aging, and that increased phosphorylation of Aβ and tau proteins, which are overexpressed in this disease and accelerates epigenetic aging. It has also been reported that DNA methylation is significantly increased in the hippocampus and entorhinal cortex of Alzheimer's disease patients. Therefore, we calculated the biological age using the Epi clock, a pan-tissue aging clock model, and confirmed that the epigenetic age of patients suffering from Alzheimer's disease is lower than their actual age. Also, it was confirmed to slow down aging.

• BMB Reports
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• 제44권5호
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• pp.291-297
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• 2011

Aging is one of the most complicated biological processes in all species. A number of different model organisms from yeast to monkeys have been studied to understand the aging process. Until recently, many different age-related genes and age-regulating cellular pathways, such as insulin/IGF-1-like signal, mitochondrial dysfunction, Sir2 pathway, have been identified through classical genetic studies. Parallel to genetic approaches, genome-wide approaches have provided valuable insights for the understanding of molecular mechanisms occurring during aging. Gene expression profiling analysis can measure the transcriptional alteration of multiple genes in a genome simultaneously and is widely used to elucidate the mechanisms of complex biological pathways. Here, current global gene expression profiling studies on normal aging and age-related genetic/environmental interventions in widely-used model organisms are briefly reviewed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1948-1950
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• 2000

Polymeric composite insulators have been in use for outdoor insulation. However, our knowledge about their long-term performance in an outdoor environment is still very limited. Especially, these insulators are subjected to the environmental stress such as ultraviolet radiation, electrical stress, mechanical load, etc.. Hence, in this paper, we simulated the factors having influence on aging of polymer insulators using the combined aging test chamber. In order to evaluate an aging characteristics with time, we measured leakage current on these insulators to make out the degree of aging.

• KIEAE Journal
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• 제12권4호
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• pp.47-57
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• 2012

The purpose of this study is to develop an aging friendly guideline aging friendly outdoor exercise environment in Universal design aspect. The aim for this guideline is to suggest a creative method to cope with forthcoming aging society and meet the various demands of all park users. Documentary survey and field survey were used to extract notion of universal design and aging friendly design; based from the extracted notions three types of exercise environment were suggested, Small scale, Medium scale and Large scale. The significant of this guideline is as fallow: First, negative aspects of aging friendly design can be eliminated by adopting universal design; therefore the guideline can have social integration aspect. Second, reflected needs of residents can be suggested on the guideline; and it was extracted from documentary survey, PPP UD checklist and field survey. Third, classifying universal design and aging friendly design in one guideline can enhance ability to manage various composition of population. Fourth, by studying young child and old people's likeness and parallel resemblance, design guideline for forthcoming aging society can be suggested. Fifth, from three developed exercise environments, the guideline can be applied into different conditions of location. Sixth, canopy type design model can be very useful for old people.

• 대한인간공학회지
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• 제33권6호
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• pp.465-475
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• 2014

Objective: The aim of this study is to investigate the effect of workload on musculoskeletal degeneration. Background: It is important that workers maintain a health body for a long time as a measure of aging workers. In order do so, it is necessary to find out if workload can effect on musculoskeletal degeneration. Method: Epidemiological studies on workload or occupation and disc degeneration, osteoarthritis of knee were identified through database and bibliography searches. Results: Epidemiological studies showed that workload certainly effect on musculoskeletal degeneration. But we couldn't know which of individual factors and occupational factors further contribute to the musculoskeletal degeneration. And we could find that studies on workload and genetic factors were very few. In addition, there was also very few studies that it was possible interaction between individual factors as obesity and occupational factors as heavy manual lifting. Conclusion: Our reviews suggest that it need to conduct study between workload and genetic factors for musculoskeletal degeneration. This further study can identify attributable risk of workload for musculoskeletal degeneration, and contribute to the measure of aging workers. Application: This paper can help to establish research plan for the measure of aging workers.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.824-829
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• 2007

Mechanical and thermal analysis properties of carbon fiber/epoxy composite for train carbody were evaluated by varying with environmental factors such as ultraviolet, temperature, and moisture. Accelerated environmental aging tester was utilized for this study. Testing temperature was set to $80^{\circ}C$ and ultraviolet was obtained through xenon-arc lamp. To consider moisture, water sprayed on specimen for 18 minutes every 2 hour. All the specimens were made of CF1263/Epoxy composite. Mechanical properties such as tensile, bending, and shear properties were evaluated through a material testing system. Also, thermal analysis properties such as storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured through dynamic mechanical analyzer. Finally surfaces of the composite exposed to environmental factors were examined using a scanning electron microscope. From experimental results, those properties of CF1263/Epoxy composite were shown to be slightly decreased due to environmental factors.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.333-338
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• 2003

Polymeric composite structures used in ground transportation applications such as the carbody of tilting train may be exposed to a ground environmental conditions during long-term missions. In this study, the degradation of mechanical and physical properties of graphite/epoxy composite and glass fabric/phenol composite under ground environmental conditions was investigated. Accelerated environmental conditions of ultraviolet radiation, temperature, and moisture were considered. Several types of specimens were used to investigate the effects of environmental conditions on mechanical properties of the composites. Also, storage shear modulus, loss shear modulus, and tan 8 were measured as a function of exposure times through a dynamic mechanical analyzer. Finally, composite surfaces exposed to environmental conditions were examined using a scanning electron microscope.

• 자원ㆍ환경경제연구
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• 제21권2호
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• pp.341-369
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• 2012

국내의 심각한 저출산 문제와 평균수명의 연장으로 인하여 고령화가 다른 어떤 나라들보다도 빠르게 진행되고 있기 때문에 고령화 문제를 심각하게 다루고 다양한 사회적 파급효과를 분석하여 대응할 필요가 있다. 따라서 본 연구에서는 고령화가 가정용 전력수요에 미치는 영향을 분석하였다. 1965년~2010년까지 46년간의 연도별 시계열 자료를 분석한 연구 결과에 의하면 가정용 전력수요는 전력가격, 소득 수준, 고령화에 유의하게 반응하고 있는 것으로 분석되었고, 특히 고령화가 가정용 전력수요에 미치는 영향은 단기적으로 더욱 크게 나타났다. 이러한 결과는 고령화가 전력수요에 복합적인 영향을 미치는데 단기적으로 수요를 감소시키는 요인이 더욱 강력하게 영향을 주는 반면, 수요를 증가시키는 요인은 장기적으로 서서히 나타나기 때문일 것이다. 그러나 장기적으로도 고령화는 가정용 전력수요를 감소시키는 것으로 나타났고, 정부가 예측한 속도로 고령화가 진행될 경우 가정용 전력수요는 연간 3%보다 낮은 수준으로 증가할 것으로 예상된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.469-472
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• 2004

There have been numerous accelerated aging laboratory tests for evaluating suitability of polymeric materials and devices. Aging test for materials and its full scale device has been conducted, but poor correlation of aging test such as service experience were observed. Service experience plays a key role in the utility section of composite insulators. A meaningful and reliable accelerated aging test is needed for evaluating composite insulator. During the service these insulators are subjected to aging stress such as humidity, pollution, and electrical field, and erosion and tracking of the weathershed occurs. This paper presents the criteria of reliability evaluation and evaluation facilities for 22.9 kV suspension composite insulator. We adopt the criteria of reliability evaluation consist of two test methods. One is CEA tracking wheel test for examining the tracking and erosion performance of composite insulator. The other is multi-stress aging test for examining effects of environmental factors such as UV, temperature, humidity, etc on composite insulator.