• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.587-594
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• 2013

The hypoglycemic and hypolipidemic effects from Wa-song (Orostachys japonicus) extracts with mixtures of medicinal herbs (such as Baekbokyung, Changchul and Sa-in) were evaluated in the streptozotocin (STZ)-induced diabetic rats. Thirty-five Sprague-Dawley rats were assigned to five groups; normal, diabetic control (D-control), a group fed a medicinal herbs mixture (D-MH), and a group fed composites of O. japonicus with mixtures of medicinal herbs (1:1, D-MHOA and 3:1, D-MHOB). All were fed on their diet for 4 weeks. After 4 weeks, the body weight of all experimental groups increased compared to the diabetic control group, with the D-MHOB group having a significantly higher increase. Fasting glucose levels in all experimental groups (compared to the D-control group) significantly decreased after 2 weeks, but between 2~3 weeks, the levels in the D-MH group were similar to the D-MHOA group. After 4 weeks, the fasting glucose level of the D-MHOB group was the lowest compared to the other groups. In a test of oral glucose tolerance, blood glucose levels were highest 60 minutes after feeding glucose; however this level improved significantly in the groups fed an experimental diet compared to the D-control group. Glycosylated hemoglobin levels were 1.9 times higher in the D-control group than the normal (3.9%), but levels in the experimental groups were significantly decreased in D-MHOA and D-MHOB groups compared to the D-MH group. In the high amounts of O. japonicus to medicinal herbs mixture, total lipids and cholesterol significantly decreased in the serum, while HDL-C levels increased. GPT activity was significantly lower in the D-MHOB group compared to the other groups. Lipid peroxide levels decreased in the D-MHOA and D-MHOB groups compared to the D-MH group. Antioxidant activity was higher depending on the dose of O. japonicus. Overall, O. japonicus exhibited effective hypoglycemic and hypolipidemic actions enhanced by a combination of medicinal herbs.

• Composites Research
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• v.15 no.4
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• pp.23-31
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• 2002

The two dimensional size effect of specimen gauge section ($length{\;}{\times}{\;}width$) was investigated on the compressive behavior of a T300/924 $\textrm{[}45/-45/0/90\textrm{]}_{3s}$, carbon fiber-epoxy laminate. A modified ICSTM compression test fixture was used together with an anti-buckling device to test 3mm thick specimens with a $30mm{\;}{\times}{\;}30mm,{\;}50mm{\;}{\times}{\;}50mm,{\;}70mm{\;}{\times}{\;}70mm{\;}and{\;}90mm{\;}{\times}{\;}90mm$ gauge length by width section. In all cases failure was sudden and occurred mainly within the gauge length. Post failure examination suggests that $0^{\circ}$ fiber microbuckling is the critical damage mechanism that causes final failure. This is the matrix dominated failure mode and its triggering depends very much on initial fiber waviness. It is suggested that manufacturing process and quality may play a significant role in determining the compressive strength. When the anti-buckling device was used on specimens, it was showed that the compressive strength with the device was slightly greater than that without the device due to surface friction between the specimen and the device by pretoque in bolts of the device. In the analysis result on influence of the anti-buckling device using the finite element method, it was found that the compressive strength with the anti-buckling device by loaded bolts was about 7% higher than actual compressive strength. Additionally, compressive tests on specimen with an open hole were performed. The local stress concentration arising from the hole dominates the strength of the laminate rather than the stresses in the bulk of the material. It is observed that the remote failure stress decreases with increasing hole size and specimen width but is generally well above the value one might predict from the elastic stress concentration factor. This suggests that the material is not ideally brittle and some stress relief occurs around the hole. X-ray radiography reveals that damage in the form of fiber microbuckling and delamination initiates at the edge of the hole at approximately 80% of the failure load and extends stably under increasing load before becoming unstable at a critical length of 2-3mm (depends on specimen geometry). This damage growth and failure are analysed by a linear cohesive zone model. Using the independently measured laminate parameters of unnotched compressive strength and in-plane fracture toughness the model predicts successfully the notched strength as a function of hole size and width.

• Elastomers and Composites
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• v.22 no.3
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• pp.204-212
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• 1987

The purpose of this study is to investigate the reinforced effect between MGF treated silane coupling agents and rubber matrix under the configuration chemical bonds, also the effect of triazine thiol compounds. For this study, vulcanizates were prepared with fifteen different compounding formulas. Their vulcanization characteristics, physical properties were examined by means of the ODR(Oscillating Dist Rheometer), the tensile tester, the benzene swelling test. The results of this study obtained are as follows: 1. In the ODR test, the MA vulcanizate was the fastest one in terms of having reached to optimum cure time($t_{90}$) and, with the same formula, when MGF vulcanizates, the shortest optimum cure times has appeared. 2. The SA, SC vulcanizates were the best the other in the physical properties such as 100%modulus, 200%modulus, 300%modulus, tensile strength. The SB vulcanizate, with higher density of crosslinking than other vulcanizates. The vulcanizates, which were filled with MGF treated with silane coupling agents we were the higher density of crosslinking than vulcanizates filled with MGF only. 3. In aging properties, the silica vulcanizates appeared to be better than the other vulcanizates. The aging Properties of treated MGF vulcanizates were similar to the silica vulcanizates. The(CR+APS+silica) and(CR+APS+MCF) were easily crosslinked by exposure to the air, and the physical properties have been improved.