• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.811-814
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• 2014

Bio-oil instability, or aging, is a significant problem for the long-term storage of fast pyrolysis oils. We investigated bio-oil aging at the molecular level using Fourier-transform ion cyclotron resonance mass spectrometry. Petroleomic analysis suggests that bio-oil aging is resulted from the oligomerization of phenolic lignin products whereas 'sugaric' cellulose/hemicellulose products have negligible effect.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.713-716
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• 2002

Aging effect on the cardiovascular circulation is simulated by lumped parameter model. Aging phenomena can be hemodynamically explained as (1) the increase of flow resistance induced by remodeling of artery vessels and increased viscosity of blood and (2) the reduction of the vessel capacitance caused by arteriosclerosis. Appropriate physiological parameters are evaluated from the clinical data of adults and old men. Simulation results well explain the hypertension with aging of cardiovascular system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.173-174
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• 2008

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.224-227
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• 2002

The relationship between the discharge aging time and the superficial layer thickness of MgO thin film was investigated in an AC PDP. The discharge characteristics of an AC PDP with the various aging time were evaluated by discharge aging experiments. We find the presence of a superficial lay which is related to the discharge characteristics during aging process. The superficial layer of MgO thin film was observed by Transmission Electron Microscope (TEM). It was found that the superficial layer thickness of MgO was dependent on discharge aging time.

• Animal cells and systems
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• v.4 no.3
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• pp.231-237
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• 2000

The effects of microgravity and hypergravity on aging are still poorly documented, particularly in mammals. However, there is a growing interest for the use of the fruit fly, Drosophila melanogaster, and this species may be now considered as a model organism in gravitational biology studies dealing with aging.

• Journal of the Korean Geographical Society
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• v.47 no.3
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• pp.359-374
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• 2012

This paper intends to examine spatial patterns and regional variations of aging population in Korea based on census data for 163 areas during 1980~2010. It briefly investigates general characteristics of aging population in Korea from previous studies and clarifies spatial patterns of aging process at regional level with reference of population growth rate at different time periods. Cities in Korea are classified into several stages including aging society, aged society and super-aged society according to the percentages of aging population out of total population every five years. At the regional scale, the stage of aging society was revealed from 1980, while the stage of aged society was shown from 1995 and super-aged society was entered from 2000 in Korea. Eighty cities in the analysis were shown at the stage of super-aged society in 2010. The portions of aging population are highly related to city size and population growth rate. For instance, the cities both in small size and with low population growth rate are revealing high percentage of aging population. As of 2010, most rural areas are staged into super-aged society, while most cities within Seoul metropolitan area and mid-sized cities are kept in the stage of aging society. At regional scale, there are no significant statistical correlations between total fertility rate and aging population.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.194-206
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• 2018

The purpose of this research is to take a look at the factors that influence the successful aging of the elderly with disability as the aging population grows. For this purpose, psychological and social concepts were defined for successful aging of the elderly with disability. It was also verified that the effects of emotional & social preparation for aging on successful aging of the elderly with disability and mediating effects of social support. The subjects of this study are 506 elderly people with disability who are over the age of 50. They were originally extracted from the 4th main survey and 3rd, 4th additional survey of Korean Retirement and Income Study. For data analysis purposes, SPSS 23.0 and SPSS PROCESS macro v2.16 were used. The results of this study are as followed. Firstly, emotional & social preparation for aging turned out to have a significant direct influence on successful aging the elderly with disability. Secondly, emotional & social preparation for aging has a indirect effect on successful aging through social support. On the basis of the results, this study provided the social welfare policy and practical suggestions to enhance the preparation for aging and social support.

• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.47-56
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• 2018

The purpose of this research is to take a look at the factors that influence the successful aging as the aging population grows. For this purpose, psychological and social concepts were defined for successful aging of the elderly with disability. It was also verified that the effects of emotional & social preparation for aging on successful aging and mediating effects of social support. The subjects of this study are 3,910 who are over the age of 65. They were originally extracted from the 4th main survey and 3rd, 4th additional survey of Korean Retirement and Income Study. For data analysis purposes, SPSS 25.0 and SPSS PROCESS macro v2.16 were used. The results of this study are as followed. Firstly, emotional & social preparation for aging turned out to have a significant direct influence on successful aging. Secondly, emotional & social preparation for aging has a indirect effect on successful aging through social support. On the basis of the results, this study provided the social welfare policy and practical suggestions to enhance the preparation for aging and social support.

• Journal of the Korean Society for Heat Treatment
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• v.32 no.5
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• pp.212-223
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• 2019

This study is to investigate the relationship between microstructural factors and tensile properties after aging heat treatment of the 15-5PH stainless steel at the temperature range of $450^{\circ}C$, $500^{\circ}C$ and $550^{\circ}C$ for various time. For the aging time of 2 hours, hardness showed maximum at $450^{\circ}C$ and then decreased with increasing aging temperature. While, hardness decreased gradually during aging $450^{\circ}C$, $500^{\circ}C$ and $550^{\circ}C$ from 1 hour to 5 hours but the hardness nearly unchanged until the 100 hours after 5 hours aging. When aging at $450^{\circ}C$, Cu atoms preferentially aggregated at the prior austenite grain boundaries and martensite lath boundaries, and Cu concentration at those boundaries was nearly unchanged even after aging for 100 hours. Therefore it was suggested that the coherency is still maintained after 100 hours aging at $450^{\circ}C$. Aging at $500^{\circ}C$ and $550^{\circ}C$ results in an increase in the concentration of Ni at the martensite lath boundaries and prior austenite grain boundaries, resulting in the formation of reversed austenite. Especially, when aged at $550^{\circ}C$ for 100 hours, the concentration of Ni remarkably increased at those boundaries, and thus the microstructure of herring bone shape was appeared. Considering the migration of Ni atom to the lath boundaries and prior austenite grain boundaries, Ni atoms contributed greatly to the formation of reversed austenite. On the other hand, it was found that Cu atoms hardly moving to those boundaries may not be contributed to the formation of reversed austenite. When aging at $450^{\circ}C$, the coarsening of the precipitated Cu atoms proceeded very slowly with increasing aging time, therefore the decrease in strengths were small but the reduction area was considerably increased due to the softening of the matrix. At the aging temperature of $500^{\circ}C$ and $550^{\circ}C$, the strengths decreased and the elongation and reduction area increased due to the appearance of the reversed austenite. Especially, the increase of reduction area was remarkable.

• Journal of the Korean institute of surface engineering
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• v.46 no.6
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• pp.235-241
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• 2013

In this study, the effects of alloying elements and thermal aging on the contact resistance of electroplated gold alloy layers were investigated by surface analysis using X-ray photoelectron spectroscopy (XPS). The contact resistance of Au-Ag alloy was lower than that of Au-Ni or Au-Co alloy after thermal aging. The XPS results show that nickel and oxygen present as nickel oxides such as NiO and $Ni_2O_3$ on the surface of gold layers after thermal aging. The increase in the contact resistance after thermal aging is attributable to the nickel oxide layer formed on the surface of the gold layers. The content of nickel diffused from the underlayer during the thermal aging was high in the order of Au-Co, Au-Ni and Au-Ag alloy because the area of grain boundary was large in the order of Au-Ag, Au-Ni and Au-Co alloy.