• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.2
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• pp.24-30
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• 2011

The accelerated aging characteristics of electroconductive papers manufactured with a mixture of carbon fiber were investigated by heating in dry oven. By accelerated aging time, the tensile strength, tensile stretch of the papers were decreased more slowly with increase of carbon fiber content, but the electrical conductivity was more rapidly decreased in case of high carbon fiber content. The weight loss of papers by thermal analysis were reduced as increasing the carbon fiber content. These results were indicated that the electrical conductivity of carbon fiber was diminished easily by heat aging, but thermal characteristic of carbon fiber was much better than that of wood pulp.

• Molecules and Cells
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• v.42 no.3
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• pp.210-217
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• 2019

The maintenance of mitochondrial function is closely linked to the control of senescence. In our previous study, we uncovered a novel mechanism in which senescence amelioration in normal aging cells is mediated by the recovered mitochondrial function upon Ataxia telangiectasia mutated (ATM) inhibition. However, it remains elusive whether this mechanism is also applicable to senescence amelioration in accelerated aging cells. In this study, we examined the role of ATM inhibition on mitochondrial function in Hutchinson-Gilford progeria syndrome (HGPS) and Werner syndrome (WS) cells. We found that ATM inhibition induced mitochondrial functional recovery accompanied by metabolic reprogramming, which has been known to be a prerequisite for senescence alleviation in normal aging cells. Indeed, the induced mitochondrial metabolic reprogramming was coupled with senescence amelioration in accelerated aging cells. Furthermore, the therapeutic effect via ATM inhibition was observed in HGPS as evidenced by reduced progerin accumulation with concomitant decrease of abnormal nuclear morphology. Taken together, our data indicate that the mitochondrial functional recovery by ATM inhibition might represent a promising strategy to ameliorate the accelerated aging phenotypes and to treat age-related disease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.25-29
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• 2004

The responses of soybean seeds were evaluated to accelerated aging and gamma irradiation with regard to germination, seed leakage, seed leachate component and dry weight of hypocotyl and primary root of the germinating seed. Accelerated aging significantly reduced the final germination rate while gamma irradiation increased the final germination rate. Furthermore, the interactive effects occurred that the final germination rate of 5-day aged seeds increased considerably in response to 4 Gy of gamma irradiation. The extent to which the electrolyte was leaked from the seeds (conductivity) was significantly affected by accelerated aging and showed a close negative correlation with the germination rate. Gamma irradiation, however, did not significantly affect the electrical conductivity of seed leachate. The accelerated aging significantly increased the concentrations of the particular electrolytes leaked from the seeds while the gamma irradiation did not affect those concentrations. Of the electrolytes leaked from the seeds, Ca and Mg showed relatively lower concentrations while K showed greater concentrations than others. Moreover, N and P showed similar responses to aging treatment. Aging treatment significantly affected dry weight (DW) of hypocotyls and primary root. Also, gamma irradiation decreased DW of hypocotyls and primary root, particularly for 8 Gy associated with 5 days aging treatment. The data were discussed in terms of the relationships of seed vigor with aging treatment and gamma irradiation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.2
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• pp.62-67
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• 2002

This paper provides the results of accelerated aging test of 18kV ZnO lightning arresters to investigate the leakage current characteristics. It was impossible to establish the replacement criterion for field operating lightning arrester because conventional aging test was only focused on the aging of ZnO elements. In general, it is possible to replace the aged arresters before the failure in the field using the leakage current measurement because it must be increased by the aging. But we can not use the method because we don't know the characteristics of the installed lightning arresters. Therefore in this paper we applied operating voltage and accelerating cycle which consists of temperature and humidity to the arresters. Then we measured the variation of total and resistive leakage current and found out the characteristics of the acted lightning arresters.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.3
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• pp.225-235
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• 2002

The color stability of current prosthetic composites is unknown, even though the quality of composite materials has been improving. This study examined the intrinsic color stability of various current prosthetic resins (ceramic-polymers) after an accelerated aging process and the extrinsic color stability after immersion in a coffee solution. By comparing the amount of discoloration after aging with that without aging, the effect of the accelerated aging process on external discoloration could be evaluated. Three current prosthetic composites (Artglass, Targis, Sculpture), one light polymerized direct composite (Z100) and one dental porcelain control (Ceramco) were assessed. The color changes (${\Delta}$E) of all the specimens were determined using the CIE $L^{*}a^{*}b^{*}$ color order system with a reflected spectrophotometer. The results were as follows: 1. The prosthetic composite materials subjected to the accelerated aging test showed no significant difference in color changes (p >.05). 2. In the coffee solution immersion test after the aging process, the color changes of the Targis and Artglass groups were not different from that of the Z100 group, which showed the highest color change. 3. In the immersion only test, a significantly high color change was observed in the sculpture glazing group. 4. The aging process influenced on the color changes more in the Targis, Artglass and Z100 groups than in the Sculpture and Ceramco groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.406-412
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• 2014

The influence of rainfall during the ripening stage on pre-harvest sprouting, seed viability, and seed quality was investigated in two Korean rice cultivars, Shindongjin and Hopum. When the rainfall was artificially treated in a greenhouse, HP started to pre-harvest sprouting at three days of rainfall treatment (DRT), but Shindongjin did not show pre-harvest sprouting at 40 DAH treatment and just 0.3~0.8% at 50 DAH, which was much lower than 15.3~25.8% of Hopum in the same treatment. After harvest, the seed germination of Hopum decreased about 10~25% compared to non-treated seeds, but that of Shindongjin decreased much little rate than that of Hopum. The seed longevity tested by accelerated aging decreased with prolonged rainfall period in both cultivars, but the varietal difference was clear; Shindongjin could withstand longer accelerated aging than Hopum. Shindongjin maintained its germination (>50%) ability after 15 days of accelerated aging regardless of the rainfall treatment period and time, but Hopum dropped below 50% germination ability after only 5 days of accelerated aging. In conclusion, rainfall during the ripening stage induced not only pre-harvest sprouting, but also reduced seed quality and longevity during storage, which varied between two cultivars.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.984-989
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• 2011

Electrical insulation is one of the most important part in a high voltage apparatus. Recently, researchers are interested in the environmental friendly vegetable oil from environmental viewpoint. Accelerated aging transformer insulating material in vegetable oil was compared to that of mineral oil. Accelerated aging oil samples produced in the oven at $140^{\circ}C$ for 500, 1000, 1500, 2000hours. And Real transformer insulation oils samples of vegetable oil and mineral oil were aged by thermal cycles repeating from $30^{\circ}C$ to $120^{\circ}C$. Samples were analyzed at 42, 63, 93, 143, 190, 240, 300 cycles. The mineral and vegetable insulating oils were investigated for breakdown voltage, water content, total acid number, viscosity, volume resistivity, insulating paper and oil permittivity, and dissolved gas analyses. The breakdown voltage of the vegetable insulating oil is higher than that found for the mineral oil; the accelerated aging progress decreased the breakdown voltage. The vegetable oil had a higher water saturation than the mineral oil; the vegetable oil has the superior water characteristics and breakdown voltage. And high viscosity of vegetable oil, care has to be taken, especially when designing the cooling system for a large transformer.

• Transactions of the Society of Information Storage Systems
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• v.10 no.1
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• pp.7-13
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• 2014

The Blu-ray Disc Recordable(BD-R) is one of strong candidates for archival application among optical media formats, because of its large capability. However, the well-defined accelerated aging test conditions and evaluation criteria have not yet been fully confirmed for BD-R. In this study, the data stability and degradation aspect of BD-R were analyzed by the random-symbol error rate(R-SER) measurement after the accelerated aging test. And a reasonable test condition of accelerated aging for BD-R and the appropriate evaluation criterion using R-SER measurement were discussed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2088-2092
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• 2011

The accelerated thermal aging of CSPE(chloro sulfonate polyethylene) of test cables were carried out for the period equal to 10, 20 and 30 years in air at $100^{\circ}C$, respectively. The CSPE cables(TAIHAN electric wire Co. Ltd) which installed in nuclear power plant for three years were used as starting materials. Condition monitering methods of the accelerated thermal aging of CSPE cables were estimated through indenter modulus and OIT(oxidation induction time) of IEC 62582, and those were newly estimated through volume electrical resistivity, ultrasound reflection time, density, FE-SEM(field emission scanning electron microscopy), XPS(x-ray photoelectron spectroscopy), EDS(energy dispersive spectroscopy), and WD-XRF(wavelength dispersive x-ray fluorescence). A new condition monitoring methods of the accelerated thermal aging of CSPE cables were generally coincident with trend of indenter modulus expect EDS, XPS and XRF. A volume electrical resistivity among new condition monitoring methods of the accelerated thermal aging of CSPE cables is excellent. It is considered that life-time of CSPE cable can be predicted through volume electrical resistivity, if CSPE jacket was aged for period such as more than 20 years.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.279-280
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• 2008

Accelerated aging tests were conducted under laboratory conditions on two generator stator bars. Electrical stress is applied in No. 1 model stator bar. Electrical and thermal stresses are applied in No. 2 model stator bar. As aging times increased from 0 to 4780h, diagnostic tests were performed on No. 1 and No. 2 model stator bars. Diagnostic tests included AC current, dissipation factor(tan$\delta$) and partial discharge magnitude. The ${\Delta}tan{\delta}$ and $\Deta$I of No. 1 and No. 2 model stator bars increased with increased in aging time.