• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.99-100
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• 2005

Reliability of the thyristor has a major effects on the high power systems such as HVDC, SVC and FACTs, etc. Therefore, analyzing method for thyristor aging is important to improve the stability of thyristor and high power systems. In this paper, we explain the analyzing method for examine the thyristor aging effect. And also, the thyristor aging experiments were performed to investigate the characteristic degradation due to the aging.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.5
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• pp.356-364
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• 2019

In this study, major problems, such as licensing problems due to civil complaints, deterioration of facility period, and damage of modules, are exposed to many problems in domestic businesses. Particularly, the photovoltaic (PV) modules applied to early PV systems have been repaired and replaced over the past two decades, and a new module-based aging detection method is needed to expand the maintenance market and stabilize and repair power supplies. PV modules in a PV system use a string that is configured in series to generate high voltage. However, even if only one module of the solar modules connected in series ages, the power generation efficiency of the aged string is reduced. Therefore, we propose a topology that can measure the instantaneous PV characteristic curve to determine the aging module in the solar string and the aging judgment algorithm using the measured PV characteristic curve.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1465-1468
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• 1997

In this study we investigated the aging characteristic such as leakage current, dielectric loss, contact angle, of EPDM for outdoor use by thermal treatment. And also observed the color change of surface, changing of chemical ingredient of the marterials by optical microscope. SEMI, FTIR and EDX at the section and surface. The test result show that leakage current is increased with thermal aging time. contact angle and dielectric loss is slightly decreased. Moreover, micro-void or crack in bulk is severely increased with aging time. However, the result affect to the tan $\delta$ at bulk of EPDM. It seems that carrier sources are removed by degassing with heat treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1035-1042
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• 1998

After the 1990's, a computer-aided partial discharge(PD) measurement system was referred in part of aging diagnosis using digital signal processing as the new technology has been studied. The PD patterns and relevant information for pattern recognition are discussed in PD research area, because discharge quantity(q), the number of discharge pulse(n) and the applied boltage phase($\varphi$) was combined with the system information of the aging state. This paper investigates the discharge phase and quantity, as well as the number of discharge(n) with regard to discharge signals generated in power cable. therefore, according to characteristic analysis on the distribution of $\varphi$, q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.932-934
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• 2006

A relationship between discharge delay time and the aging method were investigated: A-Y (Address electrode - Scan electrode) aging and conventional X-Y(Common electrode - Scan electrode) aging with the variation of sustain voltage beyond self-erasing discharge. Although A-Y aging decreases discharge delay time, it has several drawbacks like non-uniformity of discharge, degradation of luminous efficiency and a color temperature. In a conventional aging condition which is carried out near the mid-margin voltage, discharge delay time is short in low voltage and high frequency condition. As an alternative to conventional voltage aging, high voltage aging is suggested which is carried out at self-erasing sustain voltage region. High voltage aging shows lower discharge delay time and fast aging speed than conventional voltage aging.

• Journal of Korean Academy of Nursing
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• v.18 no.3
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• pp.269-280
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• 1988

Although everyone grows old, perception about the aging process and aging as measured physiologically vary widely. Perecptions of aging have psychologically influence on physical aging. This study was to examine the relationships between, self-concept, perception of aging, and physical aging in the elderly and to contribute to the theory development which may direct nursing intervention to promote well-being of the aged. Subjects were 70 women residents of a nursing home for the elderly in Seoul. Data collection was done from May 15 to June 15, 1988 using interview schedules and mechanical instruments. The instruments were selected items from the Health Self Concept Scale developed by Jacox and Stewart for self concept, and Secord and Jourad's Body Cathexis Scale and Osgood's Semantic Differential Scale for perception of aging. Physical aging was measured by mechanical instruments, inspection, questions, and palpation. The data were analysed for mean, 1-test, ANOVA, and Pearson Correlation Coefficient using an S.P.S.S computerized program. The results of the analysis were as follows. 1. The mean level of self concept for the subject group was 16.97(SD＝$\pm$6.17)in a range from 6-30. The mean level of perception of aging was 39.6. (SD＝$\pm$6.51) in a range from 13-65. The mean level of physical aging was 14.09(SD＝$\pm$2.05)in a range from 8-40. 2. Relationships among self - concept, perception of aging, and physical aging. 1) There was a positive relationship between self-concept and perception of aging(r＝0.4461, p＝0.000). 2) There was a negative relationship between physical aging and perception of aging(r＝-0.2975, p＝0.006). 3) There was a tendancy toward a negative relationship between physical aging and self -concept, but not a significant relationship (r＝-0.1033, p＝0.197). 3. 1) No general charcteristic variables were related to self concept. 2) The general characteristic variable related to the level of perception of aging was religion (t＝4. 17, p＝0.001). 3) The general characteristic variable related to the level of physical aging was age (F＝12.008, p＝0.000). There was a significant relationship between self - cencept and perception of aging, and between physical aging and perception of aging. Therefore nursing intervention should focus on promoting a positive perception of aging and strengthening self- concept during the physical aging process.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.1-7
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• 2009

Traffic accident by aging drivers is expected to be on the rise rapidly as the number of aging drivers is rising along with the aging trend being progressed. In this study, traffic accident features depending on the classification of aging population and non aging one was evaluated. As a result of this evaluation, effect factors influencing over the aging population was found to be expressed differently from that of the non aging one. Odds ratio between the aging population and non aging one was evaluated through logit model and a model with potential accident probability of the aged drivers was developed. Accident risk of the aged drivers under the condition of curved road, cutting section and moistured road was revealed to be higher than that of the non aging population.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.104-108
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• 2009

The insulation aging characteristics and structural analysis test were performed to analyze the correlations among the insulation deterioration, diagnostic results and the breakdown strength for the underground power cables. From the results of the degree of crosslinking test, hot-oil test etc., it could be confirmed that there were no manufacturing defects in the power cables under test. From the results of the water tree test and chemical structural analysis, it could be confirmed that the aging status of cable under test were very poor, especially for B-Phase and the degree of aging was increased in the orders of A, C and B-phase. From the above results, it could be concluded that the insulation aging characteristic analysis results were well consistent with the diagnostic and breakdown test results, and also confirmed that the diagnostic system under consideration was successful to discriminate the bad cables which is likely to cause cable system failure.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.320-328
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• 2017

In order to analyze the influence on derailment safety according to the aging of primary rubber springs widely applied to railway vehicles, characteristic tests were carried out on aged primary rubber spring samples. To analyze the effect of primary rubber spring aging on derailment safety, a vehicle dynamic analysis was carried out. The results of the vertical characteristics test for the rubber spring specimens with 17 years of service life revealed that the displacement restoration function was degraded due to rubber aging and the spring stiffness significantly increased. The results of the running dynamic analysis simulating the twist track running in accordance with the EN14363 standard, compared with the normal vehicle model (Case 1), showed that the derailment coefficient and the wheel unloading of the vehicle model (Case 2) using the aging primary spring characteristic increased, and the derailment safety was degraded. IN particular, it was found that the derailment safety due to the reduction of the wheel load is weak in the transient section where a steep slope change occurs.

• 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.