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Dynamic Analysis of Rockfall Impacts on Geogrid Reinforced Soil and EPS Absorption Cushions
Chaojun Ouyang,Yang Liu,Dongpo Wang,Siming He 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.1
In order to efficiently reduce the impact of rockfall, a novel shed tunnel protection system combined with geogrid reinforced soil and Expanded Polystyrene (EPS) geofoam was proposed. Transient dynamic procedures of rockfall impact were computationally analyzed by finite element methods to investigate the effects of various factors such as geogrid strength, number of geogrid layers, and height of EPS and soil cushions. A three-layered cushion system with geogrid reinforced soil and EPS can efficiently absorb the energy from rockfalls. The number and the strength of geogrid layers, as well as the height of the EPS layer have a great influence on reducing impact force and deflection of the rock-shed structure.
( Dan Li ),( Dongwei Fu ),( Yue Zhang ),( Xueling Ma ),( Liguo Gao ),( Xiaohua Wang ),( Dongpo Zhou ),( Kai Zhao ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8
The content of taxol in the bark of yews is very low, and this is not affordable from the environmental point of view. Thus, it is a necessity to look for alternative sources of taxol production to solve its supply. Currently, a large portion of the taxol in the market comes from chemical semi-synthesis, but the semi-synthetic precursors such as baccatin III and 10- deacetyl-baccatin III are extracted from needles and twigs of yew trees. Taxol-producing fungi as a renewable resource is a very promising way to increase the scale of taxol production. Our group has obtained a taxol-producing endophytic fungus, Aspergillus niger subsp. taxi HD86-9, to examine if A. niger can produce the taxanes. Six compounds from the fermentation broth of strain HD86-9 were isolated and identified by <sup>1</sup>H NMR, <sup>13</sup>C NMR, and ESI-MS. The results showed that the six compounds included four taxane diterpenoids (taxol, cephalomannine, baccatin III, and 10-deacetyl-baccatin III) and two non-taxane compounds (β-sitosterol and flavonoid isovitexin). The study verified that the taxanes can be produced by the A. niger, which is very important to taxol production via chemical semi-synthesis. Additionally, the finding is potentially very significant to solve the taxol semi-synthetic precursors extracted from needles and twigs of yew trees, and the precursor production can be easily increased through the culture condition optimization, genetic breeding, and metabolic engineering of the A. niger.