• 열처리공학회지
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• 제36권5호
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• pp.285-297
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• 2023

The effects of aging treatment sequence, specifically pre-aging and post-aging, on the microstructure and mechanical properties of Al-Zn-Mg-Cu aluminum alloys has been studied in comparison to symmetrically rolled specimens. In symmetrically rolled specimens, a straight-band precipitation distribution was observed, whereas asymmetrically rolled specimens exhibited a curved-band microstructure of fine precipitates. Notably, the asymmetrically rolled specimens displayed higher strengths. In the case of post-aging, the aging process occurred after rolling, and the dislocations generated during rolling acted as nucleation sites for precipitates during aging. This resulted in the formation of fine precipitates, contributing to improved mechanical properties compared to symmetric rolling. To enhance strength of the Al-Zn-Mg-Cu aluminum alloys, asymmetric rolling proves to be more effective than symmetric rolling, with post-aging showing greater efficacy than pre-aging.

• 대한간호학회지
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• 제46권5호
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• pp.744-752
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• 2016

Purpose: This study was done to investigate factors influencing successful aging in middle-aged women. Methods: A convenience sample of 103 middle-aged women was selected from the community. Data were collected using a structured questionnaire and analyzed using descriptive statistics, two-sample t-test, one-way ANOVA, Kruskal Wallis test, Pearson correlations, Spearman correlations and multiple regression analysis with the SPSS/WIN 22.0 program. Results: Results of regression analysis showed that significant factors influencing successful aging were post-traumatic growth and social support. This regression model explained 48% of the variance in successful aging. Conclusion: Findings show that the concept 'post-traumatic growth' is an important factor influencing successful aging in middle-aged women. In addition, social support from friends/co-workers had greater influence on successful aging than social support from family. Thus, we need to consider the positive impact of post-traumatic growth and increase the chances of social participation in a successful aging program for middle-aged women.

• 센서학회지
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• 제18권6호
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• pp.441-448
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• 2009

Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

• 한국추진공학회지
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• 제24권4호
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• pp.66-72
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• 2020

본 논문은 알루미늄 함량 변화에 따른 추진제의 후경화에 대한 영향성, 화학적 노화도에 관하여 기술하였다. 동일 경화조건에서 알루미늄 함량이 18 wt%인 추진제가 2 wt%인 추진제 대비 후경화 기간이 길어지는 것으로 확인하였다. 반면 후경화가 포함된 화학적 노화도 분석에서는 알루미늄 함량이 18 wt%인 추진제가 2 wt%인 추진제 대비 화학적 노화가 천천히 진행되는 것을 확인하였다.

• Journal of Animal Science and Technology
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• 제63권4호
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• pp.766-777
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• 2021

Bezafibrate, a fibrate drug used as a lipid-lowering agent to treat hyperlipidemia, is a pan-agonist of peroxisome proliferator-activated receptor alpha. It can enhance mitochondrial fatty acid oxidation, oxidative phosphorylation, and mitochondrial biogenesis. After ovulation, oocytes may get arrested at the metaphase II (MII) stage until fertilization beyond optimal timing, which is termed as post-ovulatory aging. Post-ovulatory aging is a disease that degrades DNA, mitochondria, and oxidative system, and has a negative impact on embryo development and quality; however, the impact of bezafibrate during post-ovulatory aging has not been fully defined. In the present study, we assessed the ability of bezafibrate to prevent the progression of aging in in vitro conditions as well as the underlying mechanisms in pigs. An appropriate concentration of this drug (50 µM) was added, and then oxidative stress, reactive oxygen species downstream, mitochondrial biogenesis, and mitochondrial function were analyzed via immunofluorescence staining and real-time polymerase chain reaction. Bezafibrate significantly alleviated reactive oxygen species and ameliorated glutathione production simultaneously in oocytes and embryos. Moreover, it diminished H2A.X and attenuated CASPASE 3 expression produced by oxidative stress in oocytes and embryos. Furthermore, bezafibrate remarkably improved the mitochondrial function and blastocyst quality as well as markedly reduced the mitochondria/TOM20 ratio and mtDNA copy number. The elevated PARKIN level indicated that mitophagy was induced by bezafibrate treatment after post-ovulatory aging. Collectively, these results suggest that bezafibrate beneficially affects against porcine post-ovulatory oocyte aging in porcine by its antioxidant property and mitochondrial protection.

• 한국축산식품학회지
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• 제41권4호
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• pp.589-607
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• 2021

Meat proteolytic systems play a crucial role in meat tenderisation. Understanding the effects of processing technologies and post-mortem storage conditions on these systems is important due to their crucial role in determining the quality characteristics of meat and meat products. It has recently been proposed that tenderisation occurs due to the synergistic action of numerous endogenous proteolytic systems. There is strong evidence suggesting the importance of μ-calpain during the initial post-mortem aging phase, while m-calpain may have a role during long-term aging. The caspase proteolytic system is also a candidate for cell degradation in the initial stages of conversion of muscle to meat. The role of cathepsins, which are found in the lysosomes, in post-mortem aging is controversial. Lysosomes need to be ruptured, through aging, or other forms of processing to release cathepsins into the cytosol for participation in proteolysis. A combination of optimum storage conditions along with suitable processing may accelerate protease activity within meat, which can potentially lead to improved meat tenderness. Processing technologies such as high pressure, ultrasound, and shockwave processing have been reported to disrupt muscle structure, which can facilitate proteolysis and potentially enhance the aging process. This paper reviews the recent literature on the impacts of processing technologies along with post-mortem storage conditions on the activities of endogenous proteases in meat. The information provided in the review may be helpful in selecting optimum post-mortem meat storage and processing conditions to achieve improved muscle tenderness within shorter aging and cooking times.

• 한국심리학회지 : 문화 및 사회문제
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• 제22권2호
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• pp.137-163
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• 2016

본 연구의 목적은 계획된 행동 이론(Theory of Planned Behavior; Ajzen, 1991)에 입각하여 중고령 근로자의 활동적 노년과 생산적 노년을 고찰하는 것으로, 노년기 행동에 대한 참여 과정에 대한 동기화 과정을 비교하였다. 이러한 동기화 요소로 활동적 노년과 생산적 노년 각각에 대한 태도, 주관적 규범, 행동 통제감을 연구하였으며, 이 세 요소가 노후준비라는 행동의도에 영향을 주는지 검증하였다. 또한, 노후준비의 세부요소가 활동적 노년과 생산적 노년 각각에 미치는 영향이 어떻게 다른지를 함께 검증하였다. 50~69세의 중고령 근로자 192명에게 설문조사를 통해 자료를 수집하였다. 분석 결과, 활동적 노년에 대해서는 주로 태도와 행동 통제감이 노후준비를 통해서 활동적 노년에 영향을 미치는 것으로 나타났다. 반면 생산적 노년에 대해서는 규범과 행동 통제감이 노후준비를 매개로 생산적 노년에 영향을 미치는 것으로 나타났다. 세부적인 분석 결과, 활동적 노년에 대해서는 사회적 노후준비를 매개 변인으로 했을 때 간접효과가 유의미했으며, 생산적 노년에 대해서는 정서적 및 사회적 노후준비를 매개변인으로 했을 때 간접효과가 유의미한 것으로 나타났다. 연구 결과를 바탕으로 중고령 근로자의 활동적 노년과 생산적 노년에 대한 시사점을 제시하였다.

• 식품보건융합연구
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• 제4권3호
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• pp.12-21
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• 2018

This research was conducted at agric physical lab, Department of Animal science, Faculty of Agriculture to determines the effects of marinating spent layer meat with basil leaf paste on drip loss and sensory attributes under different post mortem conditions. In the light of this, the poultry industry is obliged to continuously grow for a steady supply of quality poultry meat. Marinating the spent layer hen's meat with fresh basil leaves (Ocimum basilicum) in addition to subjecting the meat to 0, 6, 12, and at 24 hours post mortem aging before cooking increased it's organoleptic attributes which was readily acceptable to consumers. Marination of meat with herbs or spices like basil leaves paste had enhanced consumer's preference for taste, texture aroma, colour and overall acceptance. Marination improved consumer acceptance of spent layer meat irrespective of parts and post mortem aging. However, the majority of the respondents preferred meat marinated and subjected to 12 hours of post mortem aging. It is recommended that more quantity of marinate should be added further studies should in order to determine more effect of fresh basil leaves rough paste. And more hours of postmortem aging should be increased in order to determine more effect of fresh basil leaves rough paste marinate.

• 한국추진공학회지
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• 제23권3호
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• pp.51-57
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• 2019

HTPB 고체 추진제 기계적 물성의 후경화 효과에 대하여 시편 시험을 통하여 평가하였다. 후경화 반응 완료 후 시편 가속노화 시험을 실시하여 Arrhenius 식의 계수를 획득하였다. 확인을 위하여 원통형 모사 충전체를 설계, 제작하여 가속노화 시험을 수행하였으며, 시험 후 추진제 표면 부위, 중앙 부위, 접착 부위에 대하여 시편을 채취하여 노화 물성을 평가하였다. 측정된 결과에 대하여, 획득된 가속노화 식으로 예측하여 비교하였다. 그 결과 JANNAF 시편 시험을 통한 가속노화 식은 추진제 재료의 노화를 잘 예측하였으나 접착 부위에서는 실제 측정 결과와 차이를 나타내었다. 따라서 실기형 추진기관에서 노화 시료를 채취하는 경우 시험 목적에 부합하도록 시편 채취 부위를 선정해야 한다.

• 한국재료학회지
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• 제4권5호
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• pp.524-534
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• 1994

소량의 misch metal과 Zr을 함유한 CuZnAI형상기억 합금의 변태온도에 미치는 열사이클 및 기계적 성질 변화에 대하여 고찰하였다. 합금원소 첨가에 따라 결정립에 매우 미세화 되었으며 용체화 처리후 100~$350^{\circ}C$구간에서 경도값 변화를 조사하기 위하여 post quench aging과 step quench aging처리한 결과 $200^{\circ}C$와 $250^{\circ}C$에서 최고의 경도값을 나타냈다. $M_f$온도이하에서 인당시험한 결과 파단강도와 연실율은 결저립이 미세할수록 증가하는 경향을 보였다. 또한 파단강도는 as quenching처리한 경우보다 post quench aging처리한 경우에 보다더 증가하였다. $\beta$-상에서의 시효는 $M_s$온도를 강하시켰으며 마르텐사이트상에서의 시효는 $A_s$ 온도를 증가시켰다. post quench aging 에 따른 $A_s$의 변화는 $\beta$에서의 회복율에 기여하였으며 변태온도 ($A_s-M_s$)히스테리시스는 열사이클에 의하여 증가하는 경향을 보였다.