To estimate the relationships among bioleaching performance, additional elemental sulfur （S0）, microbial population dynamics and its energy metabolism, bioleaching of chalcopyrite by three typical sulfur- and/or iro...To estimate the relationships among bioleaching performance, additional elemental sulfur （S0）, microbial population dynamics and its energy metabolism, bioleaching of chalcopyrite by three typical sulfur- and/or iron-oxidizing bacteria, Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum and Acidithiobacillus thiooxidans with different levels of sulfur were studied in batch shake flask cultures incubated at 30 °C. Copper dissolution capability （71%） was increased with the addition of 3.193 g/L S0, compared to that （67%） without S0. However, lower copper extraction was obtained in bioleaching with excessive sulfur. Microbial population dynamics during chalcopyrite bioleaching process was monitored by using PCR-restriction fragment length polymorphism （PCR-RFLP）. Additional S0 accelerated the growth of sulfur-oxidizing bacteria, inhibited the iron-oxidizing metabolism and led to the decrease of iron-oxidizing microorganisms, finally affected iron concentration, redox potential and bioleaching performance. It is suggested that mixed iron and sulfur-oxidizing microorganisms with further optimized additional S0 concentration could improve copper recovery from chalcopyrite.展开更多
This paper investigates the heliocentric time-optimal rendezvous performance of Sun-facing diffractive solar sails with various deflection angles and acceleration capabilities.Diffractive solar sails,which generate ta...This paper investigates the heliocentric time-optimal rendezvous performance of Sun-facing diffractive solar sails with various deflection angles and acceleration capabilities.Diffractive solar sails,which generate tangential radiation pressure force,are proposed and schematically designed to achieve diverse radiation pressure distributions.The radiation pressure force model and the time-optimal control problem for these innovative Sun-facing diffractive solar sails are established.Utilizing an indirect method and the optimal control law,we explore typical heliocentric rendezvous scenarios to assess the variational trends of transfer time in relation to different deflection angles and acceleration capabilities.The results for Sun-facing diffractive sails in specific rendezvous missions are compared to reflective sails with the same area-to-mass ratio,focusing on transfer trajectory and attitude control.Our findings reveal that diffractive sails exhibit significant advantages over reflective sails,particularly in the context of normal acceleration,paving the way for more efficient space exploration.展开更多
基金Project (20803094) supported by the National Natural Science Foundation of ChinaProject (20100471233) supported by the Postdoctoral Foundation of China and the Postdoctoral Foundation of Central South University
文摘To estimate the relationships among bioleaching performance, additional elemental sulfur （S0）, microbial population dynamics and its energy metabolism, bioleaching of chalcopyrite by three typical sulfur- and/or iron-oxidizing bacteria, Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum and Acidithiobacillus thiooxidans with different levels of sulfur were studied in batch shake flask cultures incubated at 30 °C. Copper dissolution capability （71%） was increased with the addition of 3.193 g/L S0, compared to that （67%） without S0. However, lower copper extraction was obtained in bioleaching with excessive sulfur. Microbial population dynamics during chalcopyrite bioleaching process was monitored by using PCR-restriction fragment length polymorphism （PCR-RFLP）. Additional S0 accelerated the growth of sulfur-oxidizing bacteria, inhibited the iron-oxidizing metabolism and led to the decrease of iron-oxidizing microorganisms, finally affected iron concentration, redox potential and bioleaching performance. It is suggested that mixed iron and sulfur-oxidizing microorganisms with further optimized additional S0 concentration could improve copper recovery from chalcopyrite.
基金supported by the National Natural Science Foundation of China(Grant No.12372044).
文摘This paper investigates the heliocentric time-optimal rendezvous performance of Sun-facing diffractive solar sails with various deflection angles and acceleration capabilities.Diffractive solar sails,which generate tangential radiation pressure force,are proposed and schematically designed to achieve diverse radiation pressure distributions.The radiation pressure force model and the time-optimal control problem for these innovative Sun-facing diffractive solar sails are established.Utilizing an indirect method and the optimal control law,we explore typical heliocentric rendezvous scenarios to assess the variational trends of transfer time in relation to different deflection angles and acceleration capabilities.The results for Sun-facing diffractive sails in specific rendezvous missions are compared to reflective sails with the same area-to-mass ratio,focusing on transfer trajectory and attitude control.Our findings reveal that diffractive sails exhibit significant advantages over reflective sails,particularly in the context of normal acceleration,paving the way for more efficient space exploration.
