• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.55-60
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• 2018

The thermal property is one of the most important characteristics in the field of energetic materials. Because energy materials release decomposition heat, differential scanning calorimetry (DSC) is frequently used for thermal analysis. However, thermodynamic events, such as melting can interfere with DSC kinetic analysis. In this study, we use isothermal mode for DSC measurement to avoid thermodynamic issues. We also merge accelerating rate calorimetry(ARC) data with DSC data to obtain a robust prediction results for small scale samples and for large scale samples as well. For the thermal property prediction, advanced kinetics and technology solutions(AKTS) programs are used.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1320-1325
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• 2007

Retarding retrogradation of a Korean rice cake (Karedduk) added with carbohydrate materials after $0{\sim}30hrs$ of storage at $5^{\circ}C$ were investigated by Avrami equation using textural characteristics. Carbohydrate materials such as powdered sugar, trehalose, fructooligosaccharide (95%), isomalto, healtholigo, and galactooligo-saccharide (50%) were added in 0, 1, 5 or 10% levels on dry rice flour. In the amylogram, the breakdown (P-H) and consistency (C-H) for Karedduk added with carbohydrate materials were lower than those of the control. Decrease in the Avrami exponent (n) and increase in the time constant (1/k) of Karedduuk added with carbohydrate materials during storage determined by Avrami equation were important comparison factors to the control in terms of retrogradation rate analysis. The Aurami exponent (n) for control, fructooligosaccharide (95%) 10% and healtholigo 1% addition were 2.415, 1.977 and 3.297, respectively. The time constant (1/k) for fructooligosaccharide (95%) 5% and healtholigo 1% addition were lower than thecontrol. Lastly, Karedduk added with carbohydrate materials, except for fructooligosaccharide (95%) 5% and healtholigo 1% addition, was effective in retarding retrogradation.

• Journal of Korea Entertainment Industry Association
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• v.13 no.2
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• pp.169-176
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• 2019

The purpose of this study was to investigate attitudes toward aging and depression among elderly welfare facility users. For this purpose, a questionnaire-based survey was conducted with 280 elderly participants in the facilities of 15 institutions in Gyeonggi-do. In total, 258 data points were used for analysis. The measuring instruments used an attitude scale and depression scale for aging. The results of this study are as follows. First, there was no difference in attitude toward aging and depression among elderly welfare institution users by gender. Second, attitudes toward aging among elderly welfare facility users were also assessed according to final educational background. Positive attitudes in general (lack of depression) and positive attitudes toward aging were found to be higher with a higher rate of final academic completion. Third, attitudes toward aging were assessed according to experience with welfare facilities among the elderly, and it was found that depression has a significant impact on perceptions of physical change caused by aging. As a result, even when attitudes toward aging are generally negative, an elderly person cannot be judged to be depressed because this is highly related to final academic completion. Therapists working in welfare facilities for the elderly are more likely to have negative attitudes toward aging and depression when the number of facilities used is lower.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.75-82
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• 2020

In this study, extracts from the Green ball apple peel (GBE) and the newly bred green ball apple from Korea showed inhibition effects on photo-aging factor regulation associated with skin aging. To investigate the inhibition effect on photo-aging factor regulation in skin, GBE was treated with UVB to induce photo-aging related factors in CCD986sk fibroblast cells. Photo-aging factor regulation effects showed that GBE inhibited UVB-stimulated matrix metalloproteinase (MMP)-1 and MMP-9 protein synthesis in collagen type I alpha 2 chain (COL1A2), MMP-1, MMP-9, and tissue inhibitors of metalloproteinase (TIMP)-1 protein expression. The expression of COL1A2 and TIMP-1 protein was significantly increased. The mRNA expression levels of COL1A2, MMP-1, MMP-9, hyaluronan synthase (HAS)2, transforming growth factor (TGF)-β, and TIMP-1 were decreased by GBE. The expression of TIMP-1 and TGF-β, which are regulators involved in matrix metalloproteinase and type I procollagen expression, was found to increase with increasing expression of COL1A2. The expression of HAS2, which is involved in the production of hyaluronic acid, one of the structural proteins constituting the skin, was also confirmed. Therefore, GBE showed excellent efficacy against photo-aging factor regulation and could be used as functional material to prevent and treat skin aging.

• Food Engineering Progress
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• v.14 no.3
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• pp.235-242
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• 2010

This study was to investigate the combined effect of enzyme and trehalose addition on the retrogradation rate and quality changes in a Korean traditional rice cake, Backsulgi. As for the enzyme, a commercial maltogenic amylase, Novamyl, was used. From texture profile analysis and sensory tests, the optimum enzyme content for the preparation of Backsulgi was determined to be 0.1%. Backsulgi was prepared with the fixed content of Novamyl (0.1%) and different ratios (5, 10, 15%) of trehalose, and physicochemical and sensory properties were examined for 3 days of storage at ${25^{\circ}C}$. As trehalose content increased, the water activity of Backsulgi decreased. In Hunter's color value, L- and a-values of trehalose-added samples were significantly lower than those of control. In texture profile analysis, hardness of Backsulgi decreased with trehalose content. During storage, a increase in hardness and a decrease in cohesiveness were typically observed for all samples. However, those changes were significantly reduced with trehalose content. The retardation of retrogradation with the enzyme and trehalose addition was confirmed using calculated Avrami rate and time constants. These results revealed that combined treatments of 0.1% Novamyl and 10% trehalose could produce Backsulgi of better sensory quality with retarded retrogradation compared to separated treatment.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.129-132
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• 2002

대체 에너지(태양광, 풍력등)의 전력저장 시스템으로 널리 사용되는 겔형(Gel Type) 밀폐형 연(鉛)축전지의 노화 특성 평가 및 충전회로에 관하여 연구하였다. 납 합금을 이용한 기판 주조 기술과 전해액(Gel) 배합기술이 축전기 성능과 수명을 좌우하며 또한 배터리 충전 시스템에 따른 온도 상승이 치명적인 영향을 미치게 된다. 따라서 본 연구에서는 적외선 열화상 장치를 이용한 내부 열원 추적에 의해 노화정도를 측정하며 축전지 수명시험을 통해 입수한 데이터와 비교 평가하고자 한다. 현재 실험실 충방전 수명시험을 마치고 (주)코윈텍이 부안 해창 공원에 설치한 30kW급 풍력발전 시스템에 적용하여 Field Test를 시험중이다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.215.1-215
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• 2003

Bacillus polymyxa No. 26이 생산하는 생전분 당화형 $\beta$-amylase를 쌀가루 반죽시 첨가하여 45$^{\circ}C$에 5시간 둔 후 증자하여 제조한 절편을 4$^{\circ}C$ 저온실에 40시간 동안 저장하면서 기계적 검사와 관능검사에 의하여 물성과 맛을 측정하고 효소 무 첨가의 경우와 비교하여 노화억제 효과를 조사하였다. 기계적 검사시 효소 무 첨가구의 경우는 40시간까지도 굳지 않아 노화되지 않았으며, 경도, 점착성, 씹힘성에서도 큰 차이를 보였다. 관능검사시에도 경도, 촉촉함성, 단맛에 있어서 효소 첨가효과가 크게 나타났으며 떡의 제조 시 효소의 이용으로 설탕첨가를 생략할 수 있고 소화성과 맛을 좋게하므로서 품질을 향상시킬 수 있었다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.288-289
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• 2003

피부 표면 굴곡의 측정은 피부의 광노화의 정량화 , 피부관련 약품 및 기능성 화장품의 효과 평가, 피부 질환 진단 등에 반드시 필요하다. 기존에 사용되던 측정법으로는 스타일러스 (Stylus)법, 그림자(Shadowing)법, Laser Profilometry법 등이 있으나 이 방법들은 해상도 및 속도, 가격 등에 있어서 일반적으로 사용되기에는 부적합하다. 본 연구에서는 이 단점들을 극복하고 더 나은 굴곡 측정을 위해서 높은 횡·종축 해상도를 얻을 수 있는 저 결맞음 간섭계 (Low Coherence Interferometry, LCI)를 이용하여 피부 표면의 굴곡을 측정하였다.(중략)

• Elastomers and Composites
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• v.47 no.1
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• pp.9-17
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• 2012

Herein, life time prediction based on the deterioration of physical properties of chloroprene rubber (CR)aged by heat and seawater was performed. CR samples were experienced an accelerated test at $80^{\circ}C$, $100^{\circ}C$, $120^{\circ}C$ for heat aging, and $40^{\circ}C$, $60^{\circ}C$, $80^{\circ}C$ for seawater aging for 20,000 hrs. The change in tensile strength, maximum elongation,hardness was measured. As a result, the decrease in elongation was a major factor causing failure. The life time estimated using an Arrhenius model was 125 years at $23^{\circ}C$ for thermal aging and 9 years at $23^{\circ}C$ for seawater aging. SEM and elemental analysis reveal that cracks were generated and the content of oxygen was increased for CR agined by seawater. FT-IR spectrum shows the new C-O and C = O bonds were generated by the chemical reaction with seawater. Also, the glass transtion temperature was increased and the thermal decomposition was decreased by seawater aging.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.91-102
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• 1997

In order to evaluate the effects of aging on the ignition performance, pyrotechnic igniters were separated from twelve-year-old, fifteen-year-old, and sixteen-year-old live rocket motors. The characteristic values of the ignition material were measured, and the firing tests of the igniters were performed. The moisture content, the outer dimension, the crush strength, the thermal decomposition characteristics, and the heat of formation the B/$KNO_3$ ignition pellet were measured. The crush strength was increased and the heat of formation was reduced as aged, but no change was detected for other characteristic values. The burning test results of the igniter pellet in the closed bomb and the inert motor showed that the burning rate of the ignition pellet was increased by 10%, and the integration of pressure $P_t$ of the p-t curve was reduced by 15% for aged samples. It was inferred that the burning rate was increased as the crack was appeared in the pellet and $P_t$ could be proportionally decreased with the heat of explosion.