• Composites Research
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• v.17 no.1
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• pp.38-46
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• 2004

This paper aims to correlate the micro-mechanical behaviour of tow geometry with applied in-plane forces during deformation of dry woven carbon-fibre fabric. These in-plane forces lead to differences in tow reorganisation during deformation and so changes in the way in which 'lock-up' occurs. In this paper, deformation of micro-mechanical parameters such as tow interval, crimp angle, change in tow amplitude and wavelength are investigated. To observe the micro-deformation of the fabric structure, appropriate specimens from bias extension and biaxial tests are sectioned and observed under the microscope. It was found that different loading conditions cause geometric deferences in the tow architecture. The variation in deformed tow geometry with shear angle is fitted using a simple parametric model.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.47-51
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• 2006

As the recent announcement of the functional cosmetics law, the need of studies on efficacy evaluation of skin related cosmetics and medical supplies has grown. Especially to identify skin improvement, we have to compare the exact parts of the skin, however up to now it is compared only by image matching that is appeared to the human eye. This study proposes the automatical image matching system for improving the accuracy of evaluation a skin improvement. Firstly we define the feature of the skin pores and wrinkles, and extract anticipation region from skin images. And then, we calculate moments for each extracted regions and classify them as pores and wrinkles. After that, we calculate the vector by computing centroids between each regions. Through this process, we compare the vector similarities and perform the matching between existing image and reference image. To verify the efficiency of the algorithm several experiments are conducted.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.75-75
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• 2018

본 연구는 발효 옻나무와 구절초를 복합소재로 활용하여 화장품 소재로서의 개발 가능성을 확인하고자 항산화, 항주름 및 미백활성을 검증하였다. 구절초와 발효옻나무를 각각 및 각 비율별로 혼합하여 항산화 활성, 항주름 활성, 미백활성을 확인하였다. 구절초와 발효옻나무의 최적 혼합비율을 설정하기 위해 다양한 혼합비에서 선별하였으며, 구절초 1: 옻나무 9의 활성이 가장 효과적이었다. 혼합물의 DPPH, ABTS 라디칼 소거활성은 $1,000{\mu}g/ml$에서 각각 $95.78{\pm}3.24%$, $99.01{\pm}1.80%$로 나타났고, reducing power은 $1,000{\mu}g/ml$에서 $81.48{\pm}1.47%$로 확인되었다. Tyrosinase 저해활성은 $1,000{\mu}g/ml$에서 $16.74{\pm}1.85%$로, Collagenase 저해활성은 $20{\mu}g/ml$에서 $112.40{\pm}7.75%$로 나타났다. 미백 활성을 확인하기 위한 대조군으로 arbutin을 사용하였으며, B16 F10 세포를 통한 미백 활성은 혼합물 처리에 의해 tyrosinase, TRP-1, TRP-2, MITF protein 및 mRNA 발현을 유의성 있게 저해하였으며, arbutin과 유사한 효과를 나타냈다. 또한 wound healing assay를 통한 피부 장벽 손실 억제 효과를 확인하였다. 따라서 본 연구에서는 구절초와 발효옻나무의 혼합물의 높은 항산화, 항주름 및 미백활성을 통해 천연화장품의 소재로서의 높은 가치를 확인하였다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.350-356
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• 2011

Styela plicata of large (9.82~11.66 g) and small (0.93~2.21 g) sizes harvested at different times was extracted with 4 different solvents (methanol, ethanol, acetone, and water). DPPH radical scavenging and reducing power was the highest in acetone extracts of small ones (38.98% and 1.724, respectively) harvested in November. The lowest radical scavenging activity was found in water extracts of large ones (12.03% and 0.114) in December. On the other hand, large ones harvested in September showed significantly higher inhibition rate of DNA damage (water, 56.54%; methanol, 55.83%; ethanol, 48.63%) than others. Overall, the water extraction of S. plicata tended to show a higher antigenotoxic effect. In addition, water extracts of large S. plicata from November showed the highest angiotensin converting enzyme (ACE) inhibitory activity (64.38%), while that of small ones from December exhibited the lowest (51.33%). Overall the results indicate that antioxidant and antihypertensive activities S. plicata are variable depending on harvesting time, size, and extraction solvent.

• KSBB Journal
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• v.23 no.6
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• pp.529-534
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• 2008

The reactive oxygen species generated by ultraviolet rays causes various types of cutaneous damage, such as lipid peroxidation and denaturation of the extra-cellular matrix. The accumulation of such damage contributes to skin aging, especially the formation of wrinkles. This study was carried out to develop functional cosmatic by using Oriental herb supercritical extracts (OHSE) for prevention of skin. Effects of OHSE on anti-oxidation, collagenase inhibition and collagen synthesis in normal human fibroblast were investigated. OHSE showed antioxidative activity as high as vitamin C, trolox and DL-penicillamine. Also OHSE showed promotive effect on collagen synthesis and inhibitory effect on collagenase activity. From this results, we conclude that OHSE may have the potential to be conveniently used as an additive in cosmetics for prevention and improvement of skin aging.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.1
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• pp.60-69
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• 1996

3-APPA는 생체내 물질 Υ-amino butyric acid와 유사한 구조를 갖는 물질로서 human fibroblasts 3-dimensional culture system 등의 in vitro 시험에서 collagen 합성촉진 효과, 세포증식 효과를 나타내며, hairless mouse를 이용한 동물시험에서도 collagen 합성이 증가되는 것으로 보고된 바 있다. 또한 피부 안정성에서도 우수한 결과를 보여줌으로서 화장품 분야에서 새로운 노화억제 물질로서 주목을 받게 되었다. 본 시험에서는 180명의 피검자를 대상으로 3개월간의 임상시험을 통하여 새로운 노화억제 물질인 3-APPA의 효능을 기존의 GABA 유사물질, aminopropane sulfonic acid와 비교하였다. 본 시험은 double-blind, randomized, vehicle-controlled clinical study로서 180명의 피검자를 APSA군, 3-APPA군, vehicle군으로 분류한 후 3개월간 매일 저녁 취침 전, 안면에 시험제품을 사용하도록 하였으며, 사용 전, 사용 1주후, 2주후, 6주후, 12주후 5회 설문지를 통하여 피부상태를 조사하였다. 각 설문내용은 피부 건조도, 피부 탄력도, 피부 주름량, 피부 윤기도, 피부 거칠기 정도에 대한 5개 질문으로 구성된 효능에 관한 질문과 흡수정도, 끈적임, 매끄러움, 보습력, 보습지속성, 전체적인 사용감에 대한 6개 질문으로 구성된 사용성에 관한 것이었다. 각 질문에 대하여는 매우 좋음 1점, 좋은 2점, 보통임 3점, 나쁨 4점, 매우 나쁨 5점 사이에서 답할 수 있도록 하였다. 시험 결과 APSA군은 6주와 12주후 피부 건조도, 피부 거칠기 항목에서 사용전에 비하여 유의한 차이를 나타내었다. 3-APPA군은 6주후 피부 건조도, 피부 거칠기, 피부 탄력도 항목에서 시료사용전에 비해 유의한 차이를 나타내었으며 12주후에는 피부 건조도, 피부 탄력도, 피부 윤기도, 피부 거칠기 항목에서 유의한 차이를 나타내었다. 12주후 APSA군은 피부 주름, 피부 탄력도 항목에서 vehicle 사용 피검자군에 비하여 유의적인 차이를 나타내었으나 3-APPA군은 피부 탄력도, 피부 주름량, 피부 윤기 항목에서 vehicle군에 비하여 유의적인 차이를 나타내었다. 결론적으로 3-APPA와 APSA 사이에 유의적인 차이가 있지는 않았으나 3-APPA군은 APSA군에 비하여 6주, 12주에서 사용전과 유의한 차이를 나타내는 항목이 많았으며 12주에서 vehicle과 유의적인 차이를 나타내는 항목도 많으므로 3-APPA가 APSA 보다 광범위한 피부노화 억제 효과를 갖는 물질이라고 할 수 있다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.2 s.43
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• pp.37-65
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• 2003

Nowadays, we find out new anti-wrinkle-care-ingredients by in vitro searching methods using many kind of cell-culture-models for investigation of the effective anti-wrinkle-care-ingredients. But, theses new ingredients don't have effect on the human-model for anti-wrinkle, not likely on in vitro. In other words, there are so many differences between the effects on in vitro models and the clinical human models, practically. But, we actually have difficulty in putting all of the new anti-wrinkle-care-ingredients to the test on human models directly. To solve this problem, we have investigated that by using the artificial skin-culture-model or the animal model, In this lecture I will review the detail of assessment method far evaluation of anti-wrinkle agents in vitro and animal model and discuss the pros and cons of each method. Then I will present the results of Preclinical Screening trials, And especially animal model may be a good candidate for evaluation of anti-wrinkle agents.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.247-254
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• 2017

Optical Coherence Tomography (OCT) is a non-invasive imaging method that utilizes the optical scattering and interference for visualizing the surface as well as cross-sectional structures of tissue. OCT has been used for diagnosing diseases in early stage in various medical fields, but an application in cosmetics is still at early stage. In this study, OCT was adopted to evaluate skin texture and wrinkle. Results showed similar patterns of evaluation with PRIMOS in the assessment using replica. In addition, OCT produced smaller errors at different angles compared to the PRIMOS in the assessment using 3-dimensional models of wrinkles. The resolution of the image was also high enough to differentiate the images of before and after the application of makeup products. Possible use of OCT in the evaluation of fine wrinkle assessment was studied in this research. Further development of methods is necessary to provide more evidences of the effectiveness.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.3
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• pp.213-219
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• 2008

Microscale heat transfer and microfluidics have become increasingly important to overcome some very complex engineering challenges. The use of very small passages to gain heat transfer enhancement is a well documented method for achieving high heat flux dissipation. In this study, the performance evaluation of micro-channel plated heat exchangers with straight, V-shaped and Y-shaped channels has been experimentally carried out under the counterflow condition. It is found that the mixing effect in V-shaped and Y-shaped channels enhances the heat transfer but pressure drop does not increase seriously in the range of low Reynolds number.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.198-201
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• 2004

This paper aims to investigate the micro-mechanical behaviour of tow geometry with forming pressures and densities of foams during the curing process of plain weave carbon fibre fabric prepregs onto polymer foams. In order to find out and compare deformation patterns between different forming conditions, tow parameters such as amplitude and crimp angle etc. are investigated. From the observation results, geometric difference in the tow architecture with respect to forming conditions and foam characteristics were found. To observe the micro-deformation of the fabric structure, appropriate specimens from carbon fibre-foam sandwich structures are sectioned and observed under the microscope.