• Geomechanics and Engineering
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• v.19 no.5
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• pp.421-434
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• 2019

It is of great significance to study the mechanical properties and failure mechanism of the defected rock for geological engineering. The defected sandstone modeling with power-law distribution of pre-cracks was built in this paper by Particle Flow Code software. Then the mechanical properties of sandstone and the corresponding failure process were meticulously analyzed by changing the power-law index (PLI) and the number of pre-cracks (NPC). The results show that (1) With the increase of the PLI, the proportion of prefabricated long cracks gradually decreases. (2) When the NPC is the same, the uniaxial compressive strength (UCS) of sandstone increases with the PLI; while when the PLI is the same, the UCS decreases with the NPC. (3) The damage model of rock strength is established based on the Mori-Tanaka method, which can be used to better describe the strength evolution of damaged rock. (4) The failure mode of the specimen is closely related to the total length of the pre-crack. As the total length of the pre-crack increases, the failure intensity of the specimen gradually becomes weaker. In addition, for the specimens with the total pre-crack length between 0.2-0.55 m, significant lateral expansion occurred during their failure process. (5) For the specimens with smaller PLI in the pre-peak loading process, the concentration of the force field inside is more serious than that of the specimens with larger PLI.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.159-164
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• 2015

To identify new anti-inflammatory and whitening material, this study investigated the whitening and anti-inflammatory effects of the lyophilized powder from 6 oriental plant extracts (OPE; Citrus junos Tanaka, Mori cortex Radicis, Schisandra chinensis Baillon, Coix lachrymajobi var. mayuen, Angelica gigas NAKAI, and Sophora japonica L.) fermented with Streptococcus thermophilus by assessment of cytotoxicity on human dermal fibroblast, inhibitory effect of nitric oxide (NO) prodction, tyrosinase activity and melanin formation. The OPE was fermented with Streptococcus thermophilus at $37^{\circ}C$ for 2 days and the lyophilized powder was manufactured by freezing-dryer. OPE didn't show cytotoxicity at concentration of $500{\mu}g/mL$ using a cytopathic effect reduction method. OPE also exhibited inhibitory effect on nitric oxide (NO) prodction by Griess reagent system. Furthermore, OPE showed inhibitory effect on tyrosinase activity with dose dependent manner, and exhibited significant inhibition of melanin formation by measurement of melanin from culture media (p < 0.05). From these results, 6 OPE extracts showed anti-inflammatory and whitening effect and may be used as an active ingredient for cosmetics.