Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical architectures.While some biomimetic strategies have been applied in artif...Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical architectures.While some biomimetic strategies have been applied in artificial materials to enhance their mechanical stability,the simultaneous optimization of other functions along with the mechanical properties via biomimetic designs has not been thoroughly investigated.Herein,iron oxide/carbon nanotube(CNT)-based artificial nacre with both improved mechanical and electromagnetic interference(EMI)shielding performance is fabricated via the mineralization of Fe_(3)O_(4)onto a CNTincorporated matrix.The micro-and nano-structures of the artificial nacre are similar to those of natural nacre,which in turn improves its mechanical properties.The alternating electromagnetic wave-reflective CNT layers and the wave-absorptive iron oxide layers can improve the multiple reflections of the waves on the surfaces of the reflection layers,which then allows sufficient interactions between the waves and the absorption layers.Consequently,compared with the reflection-dependent EMI-shielding of the non-structured material,the artificial nacre exhibits strong absorption-dependent shielding behavior even with a very low content of wave-absorptive phase.Owing to the high mechanical stability,the shielding effectiveness of the artificial nacre that deeply cut by a blade is still maintained at approximately 70%−96%depending on the incident wave frequency.The present work provides a new way for designing structural materials with concurrently enhanced mechanical and functional properties,and a path to combine structural design and intrinsic properties of specific materials via a biomimetic strategy.展开更多
As different artificial intelligence(AI)techniques continue to evolve,power systems are undergoing significant technological changes with the primary goal of reducing computational time,decreasing utility and consumer...As different artificial intelligence(AI)techniques continue to evolve,power systems are undergoing significant technological changes with the primary goal of reducing computational time,decreasing utility and consumer costs and ensuring the reliable operation of an electrical power system.AI techniques compute large amounts of data at a faster speed than numerical optimization methods with higher processing speeds.With these features,AI techniques can further automate and increase the performance of power sys-tems.This paper presents a comprehensive overview of diverse AI techniques that can be applied in power system operation,control and planning,aiming to facilitate their various applications.We explained how AI can be used to resolve system frequency changes,maintain the voltage profile to minimize transmission losses,reduce the fault rate and minimize reactive current in distributed sys-tems to increase the power factor and improve the voltage profile.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB 0470303 and XDB 0450402)the National Key Research and Development Program of China(Nos.2018YFE0202201 and 2021YFA0715700)+2 种基金the National Natural Science Foundation of China(Nos.22293044,U1932213,and 22305240)the New Cornerstone Investigator Program.Y.-F.M.acknowledges the Major Basic Research Project of Anhui Province(No.2023z04020009)the Double First-Class University Construction Fund from USTC(No.YD2060002037).
文摘Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical architectures.While some biomimetic strategies have been applied in artificial materials to enhance their mechanical stability,the simultaneous optimization of other functions along with the mechanical properties via biomimetic designs has not been thoroughly investigated.Herein,iron oxide/carbon nanotube(CNT)-based artificial nacre with both improved mechanical and electromagnetic interference(EMI)shielding performance is fabricated via the mineralization of Fe_(3)O_(4)onto a CNTincorporated matrix.The micro-and nano-structures of the artificial nacre are similar to those of natural nacre,which in turn improves its mechanical properties.The alternating electromagnetic wave-reflective CNT layers and the wave-absorptive iron oxide layers can improve the multiple reflections of the waves on the surfaces of the reflection layers,which then allows sufficient interactions between the waves and the absorption layers.Consequently,compared with the reflection-dependent EMI-shielding of the non-structured material,the artificial nacre exhibits strong absorption-dependent shielding behavior even with a very low content of wave-absorptive phase.Owing to the high mechanical stability,the shielding effectiveness of the artificial nacre that deeply cut by a blade is still maintained at approximately 70%−96%depending on the incident wave frequency.The present work provides a new way for designing structural materials with concurrently enhanced mechanical and functional properties,and a path to combine structural design and intrinsic properties of specific materials via a biomimetic strategy.
文摘As different artificial intelligence(AI)techniques continue to evolve,power systems are undergoing significant technological changes with the primary goal of reducing computational time,decreasing utility and consumer costs and ensuring the reliable operation of an electrical power system.AI techniques compute large amounts of data at a faster speed than numerical optimization methods with higher processing speeds.With these features,AI techniques can further automate and increase the performance of power sys-tems.This paper presents a comprehensive overview of diverse AI techniques that can be applied in power system operation,control and planning,aiming to facilitate their various applications.We explained how AI can be used to resolve system frequency changes,maintain the voltage profile to minimize transmission losses,reduce the fault rate and minimize reactive current in distributed sys-tems to increase the power factor and improve the voltage profile.
文摘针对由一个发射者、一个合法接收者和一个非法接收者组成的单用户多输入多输出(MIMO,Multiple Input Multiple Output)窃听信道,研究了未知非法接收者任何信息的前提下,实现可信通信的人为干扰机制,给出了设计人为干扰的两种方式和高效的预编码算法。该算法增强了信号传播的方向性,同时最大化了人为干扰对非法接收者的影响。仿真结果表明,采用该算法的人为干扰在满足合法接收者所要求的最低信干噪声比(SINR,Signal to Interference Plus Noise Ratio)的同时,极大地降低了非法接收者的SINR。
