The effect of Gd content ranging from 6.5 wt.%to 8.5 wt.%on microstructure evolution and dynamic mechanical behavior of Mg−xGd−3Y−0.5Zr alloys was investigated by optical microscopy,X-ray diffraction,scanning electron...The effect of Gd content ranging from 6.5 wt.%to 8.5 wt.%on microstructure evolution and dynamic mechanical behavior of Mg−xGd−3Y−0.5Zr alloys was investigated by optical microscopy,X-ray diffraction,scanning electron microscopy and split Hopkinson pressure bar.The microstructure of as-cast Mg−xGd−3Y−0.5Zr alloys indicates that the addition of Gd can promote grain refinement in the casting.Due to the rapid cooling rate during solidification,a large amount of non-equilibrium eutectic phase Mg_(24)(Gd,Y)_(5) appears at the grain boundary of as-cast Mg−xGd−3Y−0.5Zr alloys.After solution treatment at 520℃ for 6 h,the Mg_(24)(Gd,Y)_(5) phase dissolves into the matrix,and the rare earth hydrides(REH)phase appears.The stress−strain curves validate that the solution-treated Mg−xGd−3Y−0.5Zr alloys with optimal Gd contents maintain excellent dynamic properties at different strain rates.It was concluded that the variation of Gd content and the agglomeration of residual REH particles and dynamically precipitated fine particles are key factors affecting dynamic mechanical properties of Mg−xGd−3Y−0.5Zr alloys.展开更多
The adsorption and leaching of chalcopyrite by two extreme thermophilic archaea(A.brierleyi and S.metallicus)and their mixture were studied.The results revealed that the chalcopyrite leaching rate of S.metallicus was ...The adsorption and leaching of chalcopyrite by two extreme thermophilic archaea(A.brierleyi and S.metallicus)and their mixture were studied.The results revealed that the chalcopyrite leaching rate of S.metallicus was slightly higher than that of A.brierleyi;the mixed system showed the highest rate.Community structure analysis during the leaching process showed that S.metallicus was maintained in a predominant state.However,the proportion of A.brierleyi in the community increased during leaching.Copper concentrations,which increased faster in the mixed system than in the single-organism systems during later stages,was related to the change of A.brierleyi in the community.Langmuir parameter analysis revealed no competitive adsorption between these two thermophilic archaea.Furthermore,qPCR(quantitative polymerase chain reaction)confirmed that adsorption was promoted between A.brierleyi and S.metallicus during mixed leaching.These findings can improve our understanding of the adsorption behaviors of mixed extreme microbial populations on mineral surfaces.展开更多
The chalcopyrite-adsorption characteristics and leaching properties of Sulfolobus metallicus（S. metallicus） YN24 were investigated in this study. The effects of zeta potentials of S. metallicus samples on chalcopyri...The chalcopyrite-adsorption characteristics and leaching properties of Sulfolobus metallicus（S. metallicus） YN24 were investigated in this study. The effects of zeta potentials of S. metallicus samples on chalcopyrite cultivated with distinct sources of energy were similar. Regardless of the energy source cultivated, all of the investigated S. metallicus samples adhered rapidly to the chalcopyrite surface, with an adhesion plateau being reached within 60 min. However, the mineral-cultured S. metallicus adsorbed more strongly onto chalcopyrite than the sulfur-cultured S. metallicus did. Furthermore, chalcopyrite-leaching tests suggested that the copper-leaching ability of the mineral-cultured S. metallicus was also greater than that of unadapted S. metallicus. Therefore, the results provide insights into the mechanism of mineral-surface adsorption of microorganisms that helps enhance the copper-leaching rate.展开更多
基金supported by the National Natural Science Foundation of China (Nos.51575289,51705270)the Key Research and Development Project of Shandong Province,China (No.2019GHY112068)the Natural Science Foundation of Shandong Province,China (No.ZR2019PEE028)。
文摘The effect of Gd content ranging from 6.5 wt.%to 8.5 wt.%on microstructure evolution and dynamic mechanical behavior of Mg−xGd−3Y−0.5Zr alloys was investigated by optical microscopy,X-ray diffraction,scanning electron microscopy and split Hopkinson pressure bar.The microstructure of as-cast Mg−xGd−3Y−0.5Zr alloys indicates that the addition of Gd can promote grain refinement in the casting.Due to the rapid cooling rate during solidification,a large amount of non-equilibrium eutectic phase Mg_(24)(Gd,Y)_(5) appears at the grain boundary of as-cast Mg−xGd−3Y−0.5Zr alloys.After solution treatment at 520℃ for 6 h,the Mg_(24)(Gd,Y)_(5) phase dissolves into the matrix,and the rare earth hydrides(REH)phase appears.The stress−strain curves validate that the solution-treated Mg−xGd−3Y−0.5Zr alloys with optimal Gd contents maintain excellent dynamic properties at different strain rates.It was concluded that the variation of Gd content and the agglomeration of residual REH particles and dynamically precipitated fine particles are key factors affecting dynamic mechanical properties of Mg−xGd−3Y−0.5Zr alloys.
基金Project (51774342) supported by the National Natural Science Foundation of ChinaProject (2016RS2016) supproted by the Hunan Provincial Science and Technology Leader (Innovation Team of Interface Chemistry of Efficient and Clean Utilization of Complex Mineral Resources),China
文摘The adsorption and leaching of chalcopyrite by two extreme thermophilic archaea(A.brierleyi and S.metallicus)and their mixture were studied.The results revealed that the chalcopyrite leaching rate of S.metallicus was slightly higher than that of A.brierleyi;the mixed system showed the highest rate.Community structure analysis during the leaching process showed that S.metallicus was maintained in a predominant state.However,the proportion of A.brierleyi in the community increased during leaching.Copper concentrations,which increased faster in the mixed system than in the single-organism systems during later stages,was related to the change of A.brierleyi in the community.Langmuir parameter analysis revealed no competitive adsorption between these two thermophilic archaea.Furthermore,qPCR(quantitative polymerase chain reaction)confirmed that adsorption was promoted between A.brierleyi and S.metallicus during mixed leaching.These findings can improve our understanding of the adsorption behaviors of mixed extreme microbial populations on mineral surfaces.
基金financially supported by the National Basic Research Priorities Program of China (No. 2010CB630905)the National High-Tech Research and Development Program of China (No. 2012AA061501)
文摘The chalcopyrite-adsorption characteristics and leaching properties of Sulfolobus metallicus（S. metallicus） YN24 were investigated in this study. The effects of zeta potentials of S. metallicus samples on chalcopyrite cultivated with distinct sources of energy were similar. Regardless of the energy source cultivated, all of the investigated S. metallicus samples adhered rapidly to the chalcopyrite surface, with an adhesion plateau being reached within 60 min. However, the mineral-cultured S. metallicus adsorbed more strongly onto chalcopyrite than the sulfur-cultured S. metallicus did. Furthermore, chalcopyrite-leaching tests suggested that the copper-leaching ability of the mineral-cultured S. metallicus was also greater than that of unadapted S. metallicus. Therefore, the results provide insights into the mechanism of mineral-surface adsorption of microorganisms that helps enhance the copper-leaching rate.
