• Journal of Life Science
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• v.26 no.6
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• pp.646-650
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• 2016

The influence of chromosome number on cell growth and cell aging was investigated in various yeast strains that have many artificial chromosomes constructed using a chromosome manipulation technique. Host strain FY833 and the YKY18, YKY18R, YKY24, and YKY30 strains harboring 16 natural chromosomes, 18 chromosomes, 18 chromosomes containing rDNA chromosome, 24 chromosomes, and 30 chromosomes, respectively, were used, and the specific growth rate of each strain was compared. The specific growth rates in the YKY18 and YKY24 strains were indistinguishable from that in the host strain, while those of the YKY18R and YKY30 strains were reduced to approximately 25% and 40% of the host strain level, respectively. Subsequently, the replicative life span was examined to investigate the relationship between the number of chromosomes and cell aging, and the life span was decreased to approximately 14% and 45% of the host strain level in the YKY24 and YKY30 strains, respectively. Moreover, telomere length, well known as a senescence factor, was shorter and more diversified in the strain, showing decreased life span. Therefore, these results suggest the possibility that an increase in the number of chromosomes containing artificial chromosomes caused cell aging, and we expected these observations would be applied to improve industrial strain harboring of versatile and special artificial chromosomes.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.5
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• pp.49-55
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• 2013

To explore the paper materials for restoration of the Annals of the Joseon Dyansty, durability of the three type of the traditional Korean Papers were estimated in this study, through moist heat artificial aging test. Three types(D, F, and G) which showed the best preservation performance in dry heat and UV treatment in the previous study were selected and artificial accelerated aging treatment with moist-heat process was conducted; the viscosity change rate was D>G>F; folding endurance G>D>F; $L^*$ value F>D>G; $a^*$ and $b^*$ change rate D>G>F; brightness decrease rate D>G>F, suggesting paper F showed the least change rate in physical/optical properties. Also the CLSM image observation showed fair coherence among fibers and confirmed paper mulberry. And in FDI extraction from each sample, paper F showed the highest value. Overall, paper F (traditional glossy paper) showed the highest stability against thermal treatment. It confirms that paper F is suitable as restoration paper for tributary remains including the annals of the Joseon Dynasty for its steady strength/viscosity decrease rate and color change rate.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.10
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• pp.465-472
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• 2002

This paper presents a study on the aging and recovery of HTV (high temperature vulcanized) silicone rubber used for outdoor insulators. UV irradiation, corona discharge and water immersion were employed as factors of the artificial aging. The effects of changes derived from these stresses on the tracking and arc resistance of silicone rubber were examined. We have investigated the aging phenomena of HTV silicone rubber by the above stresses using the surface energy calculation with contact angle measurement, solvent-extraction, and surface/volume resistivity and so on. These results showed that UV irradiation and corona discharge lead to nearly the same surface oxidation, but the percentage change of mobile low molecular weight by these stresses was different. Furthermore, the oxidized layer induced under UV irradiation restricted the recovery of hydrophobic surface. Water immersion little lowered hydrophobicity level and leaded to a loss of tracking and arc resistance. The degradation mechanism based on our results was discussed.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.123-134
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• 2007

This study was carried out for evaluating correlation of aging level and deformation resistance of asphalt mixtures conditioned by artificial aging treatment. The specimens were made of the short-term aged loose asphalt mixture which was kept in a convection oven at $154^{\circ}C$ for 2 hours, and then were artificially aged at $110^{\circ}C$ for 24, 48, 72 and 96 hours for long-term aging. Deformation strength ($S_D$) and large molecular size ratio (LMS(%)) were measured after short-term and each long-term aging treatment to evaluate aging extents of each mixture with aging time using GPC(Gel-permeation chromatograph) test. It is shown that the $S_D$ and LMS(%) were increased with aging time increment, and that LMS(%) quantity and $S_D$ have relatively good correlation each other. This study found that the aged asphalt mixture had better resistance against rutting and it was possible to estimate rutting characteristics of asphalt mixtures by using LMS(%) without a binder recovery.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.518-521
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• 2003

A new measurement system was developed by fault diagnosis system for traction motor using current signal analysis. The motor current signature analysis method is used for traction motor fault diagnosis. The diagnosis system program is constructed by artificial neural networks algorithm, those results from the program are used to train neural networks. The trained neural networks have the ability to compute adaptive results for non-trained inputs, and to calculate very fast due to original parallel structure of neural networks with high accuracy within destined tolerance. This system suggested that available test for checking, the probable extent of aging, and the rate of which aging is taking place.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.261-268
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• 2022

Recently, the number of elderly living alone suffering from loneliness and depression is also increasing significantly due to the rapid aging of the population and nuclear families. In this paper, we propose a smart aging system that increases life satisfaction by providing the elderly with the optimal service tailored to the elderly with the help of IT according to their residential environment and health status. It is possible to provide an advanced customized support system for the elderly by fully utilizing IoT, AI, and Metaverse techniques not only for the elderly who want to live an active life in society but also for the elderly who need care in a nursing hospital. The proposed system provides human satisfaction by providing social connection in real space and virtual space in accordance with the residential environment and health status to the elderly suffering from loneliness in hospital (hospital care) facilities and at home. This paper proposes a new path for future-oriented welfare policy for the elderly by providing a user-customized smart aging system by combining AI and Metaverse technology with a rapidly changing social environment.

• Journal of Korea Foundry Society
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• v.36 no.3
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• pp.88-94
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• 2016

We investigated the effect of heat treatment on an ADC12 alloy produced using diecasting. The heat treatment used in this study was a typical T6 process: a solid solution treatment followed by an artificial aging treatment. As-cast specimens were solid-solution-treated at $500^{\circ}C$ and $530^{\circ}C$ for 1-16 hr, and aged at $160^{\circ}C$ and $180^{\circ}C$ for 1-8 hr. Microstructural changes in the alloy during the heat treatment were observed. Changes in mechanical properties of the alloy were measured using a micro-Vickers hardness tester. Finally, we determined the optimal heat treatment conditions for the diecast ADC12 alloy.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.5
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• pp.64-70
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• 2013

In this study, the effect of soxhlet extraction on dewaxing of the aged beeswax-treated paper was examined. To do this, soxhlet extraction of the aged beeswax-treated paper performed with different reflux conditions and then measured the dewaxing efficiency and change in the various properties such as tensile strength, folding endurance, color and brightness. Also, an artificial aging test was executed in order to investigate the effect of soxhlet extraction on the preservability of the dewaxed paper. As the result of FT-IR analysis, a peak area of CH and COOH group, which are main band of beeswax, was decreased or removed after soxhlet extraction. The decreasing rate of each peaks were increased depending on reflux time. After dewaxing, the physical property such as MIT type folding endurance and tensile strength was decreased. And $L^*$ value and brightness were increased while $a^*$ and $b^*$ value were decreased due to the remove of color compounds in beeswax. The more color deviation (${\Delta}E$) is expected with higher reflux times. As the result of artificial aging, preservability of two dewaxed papers except of DP_SE(C) sample was higher than that of untreated paper i.e. beeswax-treated paper.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.322-327
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• 1995

Experiments were conducted to know the relationships between seed quality and leakage of sugars from differently-aged seeds of rape, Chinese cabbage and radish. Seeds were artificially aged at 90% relative humidity and 45$^{\circ}C$ to get different seed qualities. Significant amounts of total sugars were leaked from the dead seeds of all crops during the 8~24 hours soaking period, while high quality seeds leaked negligible amounts of total sugars. High quality seeds of all crops contained lots of sucrose and glucose and some stachyose, raffinose and fructose. During the artificial aging of seeds stachyose, raffinose, and sucrose decreased, while glucose and fructose increased.

• 보존과학연구
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• s.28
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• pp.5-19
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• 2007

The annals of Joseon Dynasty is the most valuable resource containing the record of Korean history and has been known as one of the UNESCO's Memory of the World Register. There was a period that the annals of Joseon Dynasty was used with beeswax to control pests. It is considered as the prior reason of damage on the annals of Joseon Dynasty. Therefore, in this study we examined the restoration paper(Hanji) as the solution of damage in the waxed volume of the annals of Joseon Dynasty. FT-IR spectrometer was used to examine traditional paper inside and outside of Korea and accelerated artificial aging paper. As a result of FT-IR analysis, spectrum did not showed its big difference in all paper used in this study. However, there was a different spectrum in paper which was made with not Broussonetia kazinoki, but Echinochloa crus-galli var. frumentacea and Dioscorea batatas. Among traditional papers in various countries, spectrum of Korean paper showed the most similarity from the annals of Joseon Dynasty. In comparison between accelerated artificial aging paper and waxed volume, we could identify the change of spectrum affected by the damage.