• 한국안전학회지
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• 제35권5호
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• pp.22-29
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• 2020

In this study, combustion and smoke release characteristics of a non-class 1E cable for nuclear power plants were investigated according to aging period. The aging was reproduced through an accelerated aging method for interval of 10 years :10, 20, 30 and 40 year, which was applied the Arrhenius equation. The cable was subjected to accelerated aging. In order to understand combustion and smoke release characteristics, the cone calorimeter test was performed according to the standard code of KS F ISO 5660-1. Heat release rate, mass loss rate, average rate of heat emission and smoke production rate were examined through cone calorimeter test. Fire performance index, fire growth index and smoke factor were derived from test results for the comparison of quantitative fire risk. When comparing the fire performance index and the fire growth index, the early fire risk tends to decrease as aging progresses, which might be attributed from the fact that the volatile substances of cables were evaporated. However, when comparing the heat release rate, average rate of heat emission and mass loss rate, which represent the mid and late periods of the fire risk, the values of accelerated aging cables were much higher than those of non-aged cable, which signifies the unstable formation of the char layer resulted in the change in the performance of flame retardants. In addition, the results from the smoke characteristics show that the accelerated aging cables were lager than the non-aged cables in terms of overall fire risk. These results can be used as baseline data when assessing fire risk of cables and establishing fire safety code for nuclear power plants.

• 한국식품영양과학회지
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• 제30권1호
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• pp.70-74
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• 2001

도축 후 장시간 냉장한 돼지 지육(생체중량 105~110 kg, B등급)에서 목심부위를 취하여 $1^{\circ}C$에서 1, 8 및 15일 숙성한 것과, 육의 중성 온도가 70, 75 및 $80^{\circ}C$가 되도록 가열한 것에 대하여 이화학적.관능적 특성을 조사하였다. 숙성기간이 길어짐에 따라 생육의 pH와 $L^{*}$(lightness)값이 높아지고, VBN 함량과 육즙 손실량이 많아진 반면 $a^{*}$(redness)값과 전단력 값은 낮아졌다. 숙성기간이 걸어짐에 따라 가열육의 경도, 저작성 및 전단력값은 낮아지고 가열감량이 적어졌으며, 연도, 다즙성 및 맛이 좋아졌으나 가열육 향기의 차이는 없고, 탄력성과 종합적인 기호성은 숙성 8일째의 것이 가장 우수하였다. 중심온도를 높게 가열할수록 경도, 저작성 및 전단력값은 높아지고 가열감량이 많으며 연도와 다즙성이 나빠졌다. 그리고 탄력성, 가열육의 향기 및 종합적인 기호성은 중심온도가 $75^{\circ}C$ 되도록 가열한 것이 가장 우수하였다.

• Applied Biological Chemistry
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• 제29권1호
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• pp.16-21
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• 1986

전분질원을 달리하여 담금한 고추장 숙성과정중의 유리당은 다음과 같다. Glucose는 숙성 전 기간을 통하여 존재하였고 경시적으로 타 유리당보다 월등히 높은 함량을 보였다. 찹쌀 고추장이 glucose 함량이 높았고 고구마 고추장이 가장 낮았다. Fructose도 숙성 전 기간을 통하여 존재하였고 함량은 1개월까지 증가 하였으나 그 이후 급격히 감소하였으며 고구마, 밀가루, 보리쌀, 찹쌀 고추장의 순으로 함량이 높았다. Maltose는 담금 직후에만 존재하였고 함량은 3.50% 미만이었다. Sucrose는 찹쌀 고추장과 밀가루 고추장에서 담금 직후에만 검출되었으나 함량은 0.4% 미만이었다. 보리쌀 고추장에서는 rhamnose도 미량 검출되 었다.

• 성인간호학회지
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• 제25권4호
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• pp.464-472
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• 2013

Purpose: The purpose of this study was to identify aging anxiety and influencing factors of middle-aged adults. Methods: Descriptive correlation design was used. Three hundred and three middle-aged adults participated in the study and completed the questionnaires in the period from September 11 to October 15 of 2011. The data was analyzed using independent t-test, one-way ANOVA, Scheff$\acute{e}$ test, Pearson correlation coefficients, and hierarchial multiple regression analysis. Results: Aging anxiety of middle-aged adults was higher than a moderate level. Socio-demographic variables such as age, religion, education, economic level, perceived health status and experience of living with older adults influenced significantly on aging anxiety. In contrast, general self-efficacy, aging knowledge and attitude toward older adults were negatively correlated with aging anxiety. Hierarchial multiple regression analysis incorporating these variables showed an explanation rate of aging anxiety at 21%. And religion, perceived health status, attitude toward older adults, and general self-efficacy were statistically significant among variables that influence on aging anxiety. Conclusion: The findings of this study suggest that senior preparation programs that can enhance self-efficacy, induce positive attitude on older adults and promote health should be implemented to reduce aging anxiety of middle-aged adults.

• Nuclear Engineering and Technology
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• 제36권5호
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• pp.475-484
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• 2004

Extending the lifetime of a nuclear power plant [(hereafter referred to simply as NPP)] is one of the most important concerns in the global nuclear industry. Cables are one of the long-life items that have not been considered for replacement during the design life of a NPP. To extend the cable life beyond the design life, it is first necessary to prove that the design life is too conservative compared with actual aging. Condition monitoring is useful means of evaluating the aging condition of cable. In order to simulate natural aging in a nuclear power plant. a study on accelerated aging must first be conducted. In this paper, evaluations of mechanical aging degradation for a neoprene cable jacket were performed after accelerated aging under tcontinuous and intermittent heating conditions. Contrary to general expectations, intermittent heating to the neoprene cable jacket showed low aging degradation, 50% break-elongation, and 60% indenter modulus, compared with continuous heating. With a plant maintenance period of 1 month after every 12 or 18 months operation, we can easily deduce that the life time of the cable jacket of neoprene can be extended much longer than extimated through the general EQ test. which adopts continuous accelerated aging for determining cable life. Therefore, a systematic approach that considers the actual environment conditions of the nuclear power plant is required for determining cable life.

• 한국세라믹학회지
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• 제46권2호
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• pp.219-223
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• 2009

Effects of MgO or $R_2O_3$(R:Dy, Ho, Yb) on the capacitance aging behavior of multilayer ceramic capacitors (MLCCs) based on $BaTiO_3$ dielectrics under DC electrical fields has been studied. At a DC field of 1 $V{/\mu}m$, the capacitance of MLCC specimens dropped immediately in a very short period (<10 s, the first stage) and then decreased continuously with time (the second stage). Mn doping significantly increased the aging rate in the second stage. The addition of MgO or $R_2O_3$ notably decreased the second stage aging rate of Mn-doped specimens. Yb doping gives rise to the lowest aging rate in the second stage, which is due to the larger population of defect dipoles associated with oxygen vacancies.

• 전력전자학회논문지
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• 제24권5호
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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.

• 한국생활과학회지
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• 제16권3호
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• pp.479-490
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• 2007

This study examines undergraduate students' intimacy toward the grandmother and their attitudes toward the elderly and aging. The study also identifies the variances that influence undergraduate students' intimacy toward the grandmother. The subjects were 397 undergraduates. Statistical analysis was conducted to examine frequency, percentage, mean, standard deviation, Cronbach's ${\alpha}$, t-test, Duncan test, ANOVA, and stepwise multiple regression. The results of this study were as follows; 1) The undergraduates' attitudes were mid-range, but their intimacy level toward their grandmother was high. 2) The undergraduates' intimacy level toward the grandmother differed significantly according to gender, experience of cohabitation, the presence of her, and religion, and it showed a significant correlation with attitudes toward the elderly and aging traits, period of cohabitation, and frequent contact with the grandmother. The undergraduates' intimacy level toward grandmother-in-low, however, was significantly different according to the religion. There was also had a significant correlation with the undergraduate students' attitudes toward the elderly and aging traits. 3) The variables that affect the undergraduates' intimacy level toward the grandmother were attitude, frequency of contact with the grandmother, gender, period of cohabitation, experience of cohabitation, and the presence of the grandmother, which explained about 35% of total variance. Attitudes toward the elderly and aging traits were very important variables for undergraduates' intimacy with their grandmother. The undergraduates' intimacy toward grandmother-in-low was affected by the variables of attitude, religion, experience of volunteer, frequency of contact with the grandmother, gender, and the presence of grandmother, which explained about 24% of the total variance. Attitude toward the elderly and aging traits were the most important variables for undergraduates' intimacy with their grandmother-in-low.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.82-87
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• 2016

This study investigates effects of an aging period on arsenic (As) chemical forms in soils and phytotoxicity using artificially As-contaminated soils with a range of As concentrations (0-300 mg/kg) and aging periods (0 and 3 months). A sequential extraction procedure showed that the increasing As concentration in soils increased the ratio of non-specifically and specifically bound As, which are known to be bioavailable. This resulted in increasing As uptake by tomatoes with increasing As concentration (R²=0.87 for exponential fitting); however, the seed germination was not sensitive to the As concentrations of the soil samples. The seed germination was also statistically similar in the soils with 75 and 150 mg-As/kg regardless of the aging period. The time taken until the seed germination (i.e., lag phase), on the other hand, decreased from 10 d to 3 d with aging for 3 months. This can be attributed to the decreased amount of bioavailable As with aging. Overall, this study shows that when the toxic effects of the As-contaminated soils are assessed using tomato plants, it is better to use more sensitive methods than seed germination such as the As accumulation or the lag phase for seed germination.

• 한국콘텐츠학회논문지
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• 제17권9호
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• pp.396-405
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• 2017

본 연구의 목적은 위계적 APC(Hierarchical Age-Period-Cohort)모형과 2006~2016년 한국복지패널자료를 활용하여 베이비부머세대를 포함한 중장년 노년층(32~76세)의 가계부채규모 결정요인을 연령(Age), 기간(Period), 코호트(Cohort)로 구분하여 분석하는데 있다. 연구 분석에 사용된 대상자는 총 86,056명이다. 연구결과에 의하면 가계부채에 영향을 미치는 요인으로 연령효과와 기간효과는 통계적으로 유의하게 나타났으나, 베이비부머세대를 포함하는 특정시기 출생연도별 코호트(Cohort)효과는 통계적으로 유의하지 않았다. 연령이 한 단위 증가하면 가계부채도 353만원 증가하였지만 가계부채 증가폭은 연령증가에 따라 점차 감소하였다. 또한 연령이외의 개인단위변수로 경제활동여부, 건강상태 등이 가계부채규모에 영향을 미치는 요인으로 작용했다. 미취업자일수록, 건강상태가 좋지 않을수록 가계부채가 증가하는 것으로 나타났다.