http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Model test and numerical simulation on the bearing mechanism of tunnel-type anchorage
Li, Yujie,Luo, Rong,Zhang, Qihua,Xiao, Guoqiang,Zhou, Liming,Zhang, Yuting Techno-Press 2017 Geomechanics & engineering Vol.12 No.1
The bearing mechanism of tunnel-type anchorage (TTA) for suspension bridges is studied. Model tests are conducted using different shapes of plug bodies, which are circular column shape and circular truncated cone shape. The results show that the plug body of the latter shape possesses much larger bearing capacity, namely 4.48 times at elastic deformation stage and 4.54 times at failure stage compared to the former shape. Numerical simulation is then conducted to understand the mechanical and structural responses of plug body and surrounding rock mass. The mechanical parameters of the surrounding rock mass are firstly back-analyzed based on the monitoring data. The calculation laws of deformation and equivalent plastic strain show that the numerical simulation results are rational and provide subsequent mechanism analysis with an established basis. Afterwards, the bearing mechanism of TTA is studied. It is concluded that the plug body of circular truncated cone shape is able to take advantage of the material strength of the surrounding rock mass, which greatly enhances its bearing capacity. The ultimate bearing capacity of TTA, therefore, is concluded to be determined by the material strength of surrounding rock mass. Finally, recommendations for TTA design are proposed and discussed.
Shengbing Duan,Guoqiang Yuan,Yanli Zhao,Weijia Ni,Hongzhen Luo,Zhongping Shi,Fan Liu 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.5
Cephalosporin C (CPC) fermentation by Acremonium chrysogenum is an extremely high oxygen-consuming process and oxygen transfer rate in a bioreactor directly affects fermentation performance. In this study, fluid dynamics and oxygen transfer in a 7 L bioreactor with different impellers combinations were simulated by computational fluid dynamics (CFD) model. Based on the simulation results, two impeller combinations with higher oxygen transfer rate (KLa) were selected to conduct CPC fermentations, aiming at achieving high CPC concentration and low accumulation of major by-product, deacetoxycephalosporin (DAOC). It was found that an impeller combination with a higher KLa and moderate shear force is the prerequisite for efficient CPC production in a stirred bioreactor. The best impeller combination, which installed a six-bladed turbine and a four-pitched-blade turbine at bottom and upper layers but with a shortened impellers inter-distance, produced the highest CPC concentration of 35.77 g/L and lowest DAOC/CPC ratio of 0.5%.
Jian Zhang,Shuai Ma,Jiawen Zhu,Kejia Kang,Guoqiang Luo,Chuandong Wu,Qiang Shen,Lianmeng Zhang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2
In this work, W/HfC composite materials were synthesized using plasma activated sintering. The influence of the sinteringtemperature and HfC weight fraction on the relative density, microstructure and compression strength were investigated. The results demonstrated that the sintering temperature and the HfC content significantly affected the microstructure of W/HfC composites. Moreover, the grain size of the W/HC composites decreased and the mechanical properties were improvedremarkably due to the addition of HfC. The majority of HfC particles reacted with oxygen impurities to generate HfO2,whichpurified the grain boundaries and refined the grain size of the W matrix. The optimum content of HfC is 2 wt%, at which ahigh compressive strength of 1.98 GPa and a high strain of 34.7% were obtained.