The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches...The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches between the parameters of the received amplitude modulation(AM) signals and the system's linear workspace and demodulation operating points can cause severe distortion in the demodulated signals. To address this, the article proposes a method for determining the operational parameters based on the mean square error(MSE) and total harmonic distortion(THD) assessments and presents strategies for optimizing the system's operational parameters focusing on linear response characteristics(LRC) and linear dynamic range(LDR). Specifically, we employ a method that minimizes the MSE to define the system's linear workspace, thereby ensuring the system has a good LRC while maximizing the LDR. To ensure that the signal always operates within the linear workspace, an appropriate carrier amplitude is set as the demodulation operating point. By calculating the THD at different operating points, the LRC performance within different regions of the linear workspace is evaluated, and corresponding optimization strategies based on the range of signal strengths are proposed. Moreover, to more accurately restore the baseband signal, we establish a mapping relationship between the carrier Rabi frequency and the transmitted power of the probe light, and optimize the slope of the linear demodulation function to reduce the MSE to less than 0.8×10^(-4). Finally, based on these methods for determining the operational parameters, we explore the effects of different laser Rabi frequencies on the system performance, and provide optimization recommendations. This research provides robust support for the design of high-performance Rydberg atom-based AM receivers.展开更多
Limiting global carbon dioxide(CO_(2))emission is imperative to alleviate global warming and meet the growing energy demand.Electrocatalytic CO_(2) reduction is a promising approach for achieving this goal.The utiliza...Limiting global carbon dioxide(CO_(2))emission is imperative to alleviate global warming and meet the growing energy demand.Electrocatalytic CO_(2) reduction is a promising approach for achieving this goal.The utilization of single atom-based catalysts(SACs)has garnered substantial attention in this particular field.Although noble metal SACs offer many advantages in CO_(2) reduction,their high cost and scarcity have deterred many researchers.Consequently,the focus has shifted toward low-priced transition metals,which have shown better performance than some rare metals.This comprehensive review focuses on the research advances in electrocatalysis for CO_(2) reduction reaction using SACs in the past five years.The main synthesis strategies of SACs in recent years are also summarized in detail.Furthermore,based on the difference in the catalytic performance and stability of different catalysts,the review summarizes the performance of non-noble metal SACs(such as Fe,Ni,Co,Mn,Cu,Sn,and Zn)with single metal sites in CO_(2) reduction reaction.The discussion of the potential mechanisms is included.Finally,the review ends by presenting an outlook on the difficulties and possibilities inherent in this developing area of single atom electrocatalytic CO_(2) reduction.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. U22B2095)the Civil Aerospace Technology Research Project (Grant No. D010103)。
文摘The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches between the parameters of the received amplitude modulation(AM) signals and the system's linear workspace and demodulation operating points can cause severe distortion in the demodulated signals. To address this, the article proposes a method for determining the operational parameters based on the mean square error(MSE) and total harmonic distortion(THD) assessments and presents strategies for optimizing the system's operational parameters focusing on linear response characteristics(LRC) and linear dynamic range(LDR). Specifically, we employ a method that minimizes the MSE to define the system's linear workspace, thereby ensuring the system has a good LRC while maximizing the LDR. To ensure that the signal always operates within the linear workspace, an appropriate carrier amplitude is set as the demodulation operating point. By calculating the THD at different operating points, the LRC performance within different regions of the linear workspace is evaluated, and corresponding optimization strategies based on the range of signal strengths are proposed. Moreover, to more accurately restore the baseband signal, we establish a mapping relationship between the carrier Rabi frequency and the transmitted power of the probe light, and optimize the slope of the linear demodulation function to reduce the MSE to less than 0.8×10^(-4). Finally, based on these methods for determining the operational parameters, we explore the effects of different laser Rabi frequencies on the system performance, and provide optimization recommendations. This research provides robust support for the design of high-performance Rydberg atom-based AM receivers.
基金supports from NSFC(U2267224)Beijing Outstanding Young Scientist.
文摘Limiting global carbon dioxide(CO_(2))emission is imperative to alleviate global warming and meet the growing energy demand.Electrocatalytic CO_(2) reduction is a promising approach for achieving this goal.The utilization of single atom-based catalysts(SACs)has garnered substantial attention in this particular field.Although noble metal SACs offer many advantages in CO_(2) reduction,their high cost and scarcity have deterred many researchers.Consequently,the focus has shifted toward low-priced transition metals,which have shown better performance than some rare metals.This comprehensive review focuses on the research advances in electrocatalysis for CO_(2) reduction reaction using SACs in the past five years.The main synthesis strategies of SACs in recent years are also summarized in detail.Furthermore,based on the difference in the catalytic performance and stability of different catalysts,the review summarizes the performance of non-noble metal SACs(such as Fe,Ni,Co,Mn,Cu,Sn,and Zn)with single metal sites in CO_(2) reduction reaction.The discussion of the potential mechanisms is included.Finally,the review ends by presenting an outlook on the difficulties and possibilities inherent in this developing area of single atom electrocatalytic CO_(2) reduction.
