• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.109-112
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• 2002

The structural and optical features of Porous Silicon(PS) were investigated; the porous silicon was prepared by electrochemical etching of silicon wafers in HF solution. The morphologies and Photoluminescece(PL) features of the PS were investigated in terms of etching time, current density and aging conditions. The average pore diameter and pore depth were determined by current density and etching time, respectively. As-prepared PS exhibited the maximum PL peak at the wavelength of ∼ 450 nm. The degree of deviation from as-prepared PS during aging treatment seemed to depend on the microstructure as well as morphology of the PS. It is found that etching current density played an important role on the microstructural features of the PS.

• Journal of the Korea Construction Safety Engineering Association
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• s.55
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• pp.10-17
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• 2012

Aging society may approached to our society during snatch very, and enter in super aging society for more span. Investment that we which live 21th century are many in people's quality of life elevation meantime did not consist, but stand in visual point that must improve many portions forward. For front, repletions for many equipments that consider aged on our society must consist, and much researches may have to be gone for this. According to traffic accident result, percentage of older pedestrian deaths was 46.5% as much in Korea. In particular, the crossing accidents by 59% or more of the older pedestrian traffic safety measures that target is an urgent situation. Therefore, in this study was to identify the domestic status and problem on no-sidewalk region for older pedestrians. In addition, side walk the installation and maintenance plan presented to prepare for aging society.

• BMB Reports
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• v.50 no.4
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• pp.160-161
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• 2017

Proper maintenance of biological components is crucial for longevity and healthy aging. Although the role of homeostatic maintenance systems for DNA and protein in longevity is established, it remains largely unknown for RNA. In our recent work, we show that nonsense-mediated mRNA decay (NMD) promotes longevity in the roundworm C. elegans by enhancing RNA quality control. We find that the activity of NMD decreases during aging, raising the possibility that RNA quality declines in old animals. We then show that key components of NMD complex are required for prolonged lifespan in C. elegans. In addition, animals with reduced insulin/insulin-like growth factor-1 (IGF-1) signaling (IIS), a representative longevity model, display increased NMD activity. Thus, up-regulation of NMD appears to play crucial roles in longevity conferred by reduced IIS via enhancing mRNA quality control. As both IIS and NMD pathways are evolutionarily conserved, mammals including humans may be equipped with similar RNA quality control systems to achieve longevity.

• Journal of Korea Foundry Society
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• v.30 no.4
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• pp.142-146
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• 2010

To elucidate the characteristics of cavitation erosion of super duplex stainless steel, a cavitation erosion test, an optical microstructure, a hardness test, and a transmission electron microscope (TEM) analysis were conducted. As aging time at $475^{\circ}C$ increased, the hardness of ferrite phase increased whereas that of austenite phase was nearly constant. The reason why the cavitation erosion resistance increased with an increase of aging time was due to the formation of W-rich phases (${\alpha}$') of a nanometer scale with the high hardness that were precipitated within ${\alpha}$-grains and at ${\alpha}$-grain boundaries during aging, compared with that of the solution annealed alloy.

• Journal of Power System Engineering
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• v.18 no.3
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• pp.14-19
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• 2014

The purpose of the study is to investigate the effect of additive catalyst according to the thermal aging of vanadia SCR catalysts. At a fresh condition, the $3V_2O_5-5WO_5-92TiO_2$ SCR showed the highest NOx conversion rate of about 30%, the performance of 5 kinds of SCR to which additive catalysts were added was not improved due to the insignificant effect of acid site control. For catalysts aged for 12h at $700^{\circ}C$, the SCR to which 3wt% Zeolite was added decreased in NOx conversion rate by 2.5% on average compared to the fresh SCR, it showed higher thermal durability than other additive catalyst. For 3Zeolite with high performance of NOx conversion rate during thermal aging, the Zeolite with stronger durability at a high temperature than other 5 kinds of SCR catalysts decreased the sintering of catalysts.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.1
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• pp.10-16
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• 1998

The softening behavior of squeeze cast Mg-Li-Al and Mg-Li-Al-Zr alloys have been investigated. The highest hardness values of Mg-Li-Al and Mg-Li-Al-Zr alloys were obtained after solution treatment at $400^{\circ}C$ for 1 hour. The hardness value, however, decreased as the aging temperature and time increased. Microstructural and calorometric analyses showed that quenched-microstructure changed from primary (${\alpha}$ and ${\beta}$)+secondary ${\alpha}$ to primary(${\alpha}$ and ${\beta}$)+secondary ${\alpha}+{\theta}$ after aging. The softening during aging was due to the coarsening of ${\theta}$ precipitates.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.216-219
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• 2007

Effects of aging treatment of doped-MgO electron emission layer on luminance efficiency of ac-PDP were investigated in this study. Morphological and luminance efficiency with aging treatment were examined, especially with emphasis on the effects of doping elements. The results indicate that the luminance efficiency of test panels depends on the type of doping elements used for MgO and that may be due to the redeposition of MgO during glow discharge.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1105-1111
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• 2007

Because forest fire can give a serious damage to overhead conductors, the thorough understanding about aging behavior of burned conductor is very important in maintaining the transmission line safely. Therefore, a systematic investigation was carried out by heating method. As the heating temperature increases, drastic change of tensile strength of Al wire due to the softening of Al wire occurred. When Al wire is exposed to the flame(about $800\;^{\circ}C$) during only 13 seconds, the remained tensile strength of Al wire showed under 90 %. The detailed results will be given in the text.

• YAKHAK HOEJI
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• v.21 no.2
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• pp.101-109
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• 1977

The effect of humidity on the aging process of hydrous aluminum oxide prepared by the reaction of aluminum chloride and sodium bicarbonate solution at pH 7.8, which was then kept in various atmosphere under relative humidity at 37.deg. was observed by the measurements of acid consuming capacity, X-ray diffraction and IR absorption. The humidity was one of the important factors influencing the aging process of hydrous aluminum oxide during storage. The higer the humidity, the more was accelerated age, crystalize and loss in acid reactivity. Depending on the humidity, the aging product was different, especially, in the case of up to the relative humidity of 72%, it forming bayerite. On the other hand, the hydrous aluminum oxide aged below the relative humidity of 50% was still amorphous even after 120 days storage. When hydrous aluminum oxide was aged under higher humidity, definite IR absorption bands develop as the hydroxys become part of an ordered structure, and it showed their characteristic absorption band around 1630 and 1060 cm$^{-1}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.534-535
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• 2007

Because forest fire can give a serious damage to overhead conductors, the thorough understanding about aging behavior of burned conductor is very important in maintaining the transmission line safely. Therefore, a systematic investigation was carried out by heating method. As the heating temperature increases, drastic change of tensile strength of Al wire due to the softening of Al wire occurred. When Al wire is exposed to the flame(about $800^{\circ}C$) during only 13 seconds, the remained tensile strength of Al wire showed under 90%. The detailed results will be given in the text.