The exploration of active and robust electrocatalysts for both the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is the bottleneck to realize the commercialization of rechargeable metal-air batteries...The exploration of active and robust electrocatalysts for both the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is the bottleneck to realize the commercialization of rechargeable metal-air batteries and regenerative fuel cells.Here we report facile synthesis of three-dimensional(3 D)carbon nanotube(CNT)/carbon composites using earth-abundant coal as the carbon source,hydrogen reductant and heteroatom dopant to grow CNTs.The prepared composite featuring 3 D structural merits and multiple active sites can efficiently catalyze both ORR and OER,affording high activity,fast kinetics,and long-term stability.With the additional incorporation of manganese,the developed catalyst afforded a potential difference of 0.80 V between ORR at the half wave potential and OER at a current density of 10 mA cm^(-2).The optimized sample has presented excellent OER performance within a constructed solar-powered water splitting system with continuously generating oxygen bubbles at anode.Notably,it can be further used as a durable air-electrode catalyst in constructed Zn-air battery,delivering an initial discharge/charge voltage gap of 0.73 V,a remained voltaic efficiency of 61.2%after 160 cycles and capability to power LED light for at least 80 h.This study provides an efficient approach for converting traditional energy resource i.e.coal to value-added alternative oxygen electrocatalysts in renewable energy conversion systems.展开更多
We propose the modified Kalman filter(MKF) using the received signal for observation and constructing an inverse process of the conventional Kalman filter(CKF) for polarization de-multiplexing in coherent optical(CO) ...We propose the modified Kalman filter(MKF) using the received signal for observation and constructing an inverse process of the conventional Kalman filter(CKF) for polarization de-multiplexing in coherent optical(CO) orthogonal frequency-division multiplexing(OFDM) transmissions. The MKF can avoid the convergence error problem in CKF without matrix inverse operation and has a faster converging speed and a much larger tolerance to the process and measurement noise covariance, about two orders of magnitude more than those of CKF. We experimentally demonstrate the 12 Gbaud OFDM signal transmission over 480 km standard singlemode fiber. The performance of MKF and CKF outperforms pilot-aided polarization de-multiplexing with better accuracy and nonlinearity tolerance.展开更多
基金The financial supports from the National Natural Science Foundation of China(21605067,21763023)Talent Project Grant of the University of Science and Technology Liaoning(601011507-06)Doctoral Start-up Research Funding of the University of Science and Technology Liaoning(USTL010178),China。
文摘The exploration of active and robust electrocatalysts for both the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is the bottleneck to realize the commercialization of rechargeable metal-air batteries and regenerative fuel cells.Here we report facile synthesis of three-dimensional(3 D)carbon nanotube(CNT)/carbon composites using earth-abundant coal as the carbon source,hydrogen reductant and heteroatom dopant to grow CNTs.The prepared composite featuring 3 D structural merits and multiple active sites can efficiently catalyze both ORR and OER,affording high activity,fast kinetics,and long-term stability.With the additional incorporation of manganese,the developed catalyst afforded a potential difference of 0.80 V between ORR at the half wave potential and OER at a current density of 10 mA cm^(-2).The optimized sample has presented excellent OER performance within a constructed solar-powered water splitting system with continuously generating oxygen bubbles at anode.Notably,it can be further used as a durable air-electrode catalyst in constructed Zn-air battery,delivering an initial discharge/charge voltage gap of 0.73 V,a remained voltaic efficiency of 61.2%after 160 cycles and capability to power LED light for at least 80 h.This study provides an efficient approach for converting traditional energy resource i.e.coal to value-added alternative oxygen electrocatalysts in renewable energy conversion systems.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.61420106011,61871408,and 61871082)
文摘We propose the modified Kalman filter(MKF) using the received signal for observation and constructing an inverse process of the conventional Kalman filter(CKF) for polarization de-multiplexing in coherent optical(CO) orthogonal frequency-division multiplexing(OFDM) transmissions. The MKF can avoid the convergence error problem in CKF without matrix inverse operation and has a faster converging speed and a much larger tolerance to the process and measurement noise covariance, about two orders of magnitude more than those of CKF. We experimentally demonstrate the 12 Gbaud OFDM signal transmission over 480 km standard singlemode fiber. The performance of MKF and CKF outperforms pilot-aided polarization de-multiplexing with better accuracy and nonlinearity tolerance.
