• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.555-557
• /
• 2000

원자력 발전소에서 사용되어지는 케이블은 전원 및 제어신호를 안정하게 전달하는 역할을 하며, 비상상태 발생시에는 원자로를 안전하게 shut-down시키는 통로 역할을 하므로 매우 중요하다. 케이블 상태 감시시 절연 및 피복재료는 종류 및 배합내용이 다양하기 때문에 종래의 자료로부터 전선과 케이블의 열화 또는 수명을 추정하기가 극히 어려우며 방사선에 노출이 되는 케이블의 경우 노화현상의 진행이 빠르고 방사선 열화로 수명이 단축되므로 국내 실정을 감안한 독자적인 검증방법 도출, 규제기술 기반 구축 필요 및 규제의 합리화와 효율화 필요성이 대두되고 있다. 기존에 사용해온 케이블 진단 방법에는 절연 파괴 강도 측정을 통한 노화진단, 산화 방지능력 측정을 통한 노화진단, 자켓 및 절연체의 판단, 연신율에 의한 노화진단, 케이블 Indenter에 의한 노화진단, 온도 및 방사선 등의 특정상태에 대한 평가, 유사한 환경조건에 대한 주기적 검토 등이 있다. 기존의 국내외 케이블 상태 감시방법을 조사 연구하므로서 케이블 열화에 대비한 수명관리 규제 기술 및 상태감시 (Condition Monitoring : CM) 기술의 평가 기준을 결정 하고자 한다.

• The Korean Journal of Food And Nutrition
• /
• v.16 no.2
• /
• pp.105-110
• /
• 2003

The effect of varietal differences of rice starches by amylose content and gel consistency on the retrogradation behavior was studied. The gel consistency test, which is designed to detect differences in the texture of cooked rice of varieties that have a similar amylose content, had been turned out to be useful in this study. Both Suwon 232 and San Li Cun had higher amylose content, but were greatly different in gel consistency values. The results showed that setback viscosity of rice flour measured in a Brabender amylograph was significantly affected by amylose content as well as gel consistency. Increase in the rigidity modulus (E) of rice starch gels during storage determined by using Texture analyzer indicated that amylose content was an important factor in terms of hardness development The study of Avrami kinetics of retrogradation showed that time constant of rice starch gels was influenced by amylose content, but not by gel consistency.

• 건강소식
• /
• v.30 no.7 s.332
• /
• pp.24-25
• /
• 2006

노인의 피부는 노화로 말미암아 여러 가지 문제가 생길 수 있따. 그러나 적절하게 관리하지 못하여 여러 가지 피부 질환으로 고생하게 되는 경우가 많다. 노인에게 올 수 있는 피부 문제를 알고 대처하는 것이 중요하다. 흔히 노인들은 외모의 변화를 심각하게 고민하지만, 생명과 관련이 없는 현상이기 때문에 무관심하게 되고, 적절한 관리를 받을 기회를 놓쳐 심각한 피부 질환으로 진행되기도 한다. 노인들은 피부의 변화와 주름을 창피하거나 부끄럽게 생각하지 말고, 자신의 삶의 일부를 나타내는 행복의 선으로 받아들여야 한다. 또한 이를 성형수술이나 화장으로 감추려 하지 말고 적절한 관리를 통해 가능하다면 피부 노화가 느리게 올 수 있도록 관리하는 것이 중요하다. 노인에게서 흔한 피부 질환은 피부 소양증, 대상포진, 피부 건조증, 피부암 등이 있다.

• Journal of Life Science
• /
• v.29 no.7
• /
• pp.817-823
• /
• 2019

Immune system provides defense integrity of body against external invaders. In order to accomplish the important defending role immune system is composed of many different components which are regenerated continuously during lifespan. The key components are professional killing cells such as macrophage, neutrophil, natural killer cell, and cytotoxic T cell and professional blocking molecule, antibody, which is produced by plasma cell, the terminal differentiated B cell. Immune response is orchestrated harmoniously by all these components mediated through antigen presenting cells such as dendritic cells. Immune responses can be divided into two ways: innate immune response and adaptive immune response depending on induction mechanism. Aging is a broad spectrum of physiological changes. Likewise other physiological changes, the immune components and responses are wane as aging is progressing. Immune responses become decline and dysregulating, which is called immunosenescense. Immune components of both innate and adaptive immune response are affected as aging progresses leading to increased vulnerability to infectious diseases. Numbers of immune cells and amounts of soluble immune factors were decreased in aged animal models and human and also functional and structural alterations in immune system were reduced and declined. Cellular intrinsic changes were discovered as well. Recent researches focusing on aging have been enormously growing. Many advanced tools were developed to bisect aging process in multi-directions including immune system area. This review will provide a broad overview of aging-associated changes of key components of immunity.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1996.05a
• /
• pp.41-47
• /
• 1996

데토네이션 현상은 화학반응면이 음속 이상으로 진행하는 경우로 연소와는 다른 분야로 취급된다. 국내에서는 발파나 무기에 응용되고 있지만 이 분야의 선진국에서는 산업의 여러 분야에 적용되며 이 분야에 많은 기초연구가 행해져 왔다. 본 연구는 이러한 데토네이션 현상을 콘크리이트나 금속의 절단이나 노화된 구조물의 해체에 응용하는 것에 관한 내용으로 고체폭약에 비해 위험하여 취급이 어려운 액체 폭약을 보다 안전하고 현상변화가 자유로운 액체의 잇점을 살려 절단에 있어 최대의 효율을 내는 형상을 단지 케이스의 가공만으로 가능하므로 경제적이다.

• Korean Journal of Food Science and Technology
• /
• v.8 no.3
• /
• pp.185-190
• /
• 1976

• Journal of the Korean Society of Propulsion Engineers
• /
• v.9 no.4
• /
• pp.23-30
• /
• 2005

The Hygrothermal aging of the laminates of $Avimid^(R)$ K3B/IM7 in $80^{\circ}C$ water was studied as a function of immersion time prior to forming microcracks. The factors causing the $80^{\circ}C$ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses or the interfacial damage between the fiber and the matrix. The times to saturation in $80^{\circ}C$ water for the laminates and for the neat resin were 100 hours and 500 hours. After 500 hours aging of the neat resin, the glass transition temperature was changed less than 1% by DSC test, and the weight gain was 1.55% increase with the diffusion coefficient $7\times10^{-6}m/s^2$ and the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the ${[+45/0/-45/90]}_s$ K3B/IM7 laminates in $80^{\circ}C$ water, the weight gain was 0.41% increase with the diffusion coefficient $1\times10^{-6}m/s^2$. In 100 hours, the loss of the fracture toughness of the laminates was 43.8% of the original toughness by the microcracking fracture toughness criterion. Therefore, the main factor to degrade the microcracking toughness of the laminates could be the degradation of the matrix fracture toughness.

• Korean Journal of Cognitive Science
• /
• v.24 no.1
• /
• pp.1-24
• /
• 2013

The elderly population continues to increase in Korea and there has been a growing interest in understanding normal aging. In response to this public interest, the present paper reviewed human aging research focusing on recently published neuroimaging studies. For the first half of the paper, I reviewed the effects of aging on the brain and cognition. In normal aging, structural changes in the brain include atrophy and volume reduction in the prefrontal and temporal cortices. Functional changes are exhibited in the form of overactivation of the brain. Moreover, age-related cognitive decline is particularly observed in inhibition and memory, which are also associated with the age-related structural changes in the brain. For the second half of the paper, I introduced physical exercise studies showing that exercise played a protective role in the age-related neurocognitive decline. More specifically, engaging in physical exercise (particularly, aerobic exercise) for a relatively long period of time (e. g., > 6 mon.) protected older adults from volume loss in the prefrontal cortex and the hippocampus, and induced better inhibition and memory. These exercise-induced benefits appear to be associated with changes in neuronal levels, indicating that the aging brain is still plastic and this plasticity can be enhanced by physical exercise.

• Applied Microscopy
• /
• v.38 no.2
• /
• pp.107-115
• /
• 2008

The filtration barrier of kidney consists of endothelial cell, glomerular capillary, glomerular basement membrane, mesangial matrix, and podocyte. In aged rats, the morphological changes were shown in various parts, including the glomerulus. These changes were thickening of basement membrane and mesangial matrix, crescent formation of glomerular capillary, deformity of foot processes, glomerular sclerosis and obsolescence. But these glomerular morphologies are partial images or few serial images analysis. In this study, we examined the morphological alteration of glomerulus in the young and aged rats by light microscopy, transmission electron microscopy and three dimensional reconstruction. We were found in aged rat glomerulus, expansion of urinary space and mesangial matrix, thickening and degrading of glomerular basement membrane, decreasing in podocyte foot processes, fragmentation of podocytic nucleus membrane. These observations indicate that may provide useful data for investigating the pathogenesis of age-related dysfunction of kidney.

• Composites Research
• /
• v.22 no.6
• /
• pp.39-44
• /
• 2009

The effect of exposure times on the aging characteristics of carbon fiber/epoxy composite ring specimen was evaluated using an accelerating aging tester. Combined exposure conditions, such as temperature, moisture, and ultraviolet, were applied up to 3000 hours. Tensile properties and flexural properties including the effect of curvature were evaluated on the specimens subject to various exposure times through a material testing system. Their aging surfaces were observed through a scanning electron microscope. According to the results, tensile modulus was little affected by the exposure times. However, tensile strength, at the early stage of the exposure times, increased due to physical aging and curing reaction, but tensile strength slightly decreased due to degradation as the exposure times increased. The flexural modulus and flexural strength increased at the early stage of the exposure times, but slightly decreased as the exposure times increased. Aging surfaces of the specimens examined using the scanning electron microscope revealed a different morphology in various exposure times and provided useful information for identifying the degradation in mechanical properties of the composite subject to various exposure times.