The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challengin...The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms.Herein,the chiral CNCs are first synthesized on a threedimensional(3D)carbon foam and then combined with the FeNi/NiFe_(2)O_(4) nanoparticles to form a novel chiral-dielectric-magnetic trinity foam.The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss.The formation of the FeNi-carbon interfaces induces interfacial polarization loss,which is confirmed by the density functional theory calculations.Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects,which enhance the magnetic anisotropy and magnetic loss capability.Owing to the synergistic effect between dielectricity,chirality,and magnetism,the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth(EAB)of 14 GHz and a minimum reflection of loss less than-50 dB.More importantly,the C-band EAB of the foam is extended to 4 GHz,achieving the full C-band coverage.This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.展开更多
This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passi...This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passive sensing scheme.The scheme is based on the radio frequency(RF)fingerprint learning of the RF radio unit(RRU)to build an RF fingerprint library of RRUs.The source RRU is identified by comparing the RF fingerprints carried by the signal at the receiver side.The receiver extracts the channel parameters from the signal and estimates the channel environment,thus locating the reflectors in the environment.The proposed scheme can effectively solve the problem of interference between signals in the same time-frequency domain but in different spatial domains when multiple RRUs jointly serve users in CF-RAN architecture.Simulation results show that the proposed passive ISAC scheme can effectively detect reflector location information in the environment without degrading the communication performance.展开更多
重症患者常因创伤、手术、应激、疾病等多种因素,导致患者血糖变异性升高。医务人员提高对重症患者血糖的精细化管理能力,对改善重症患者预后至关重要,血糖监测在重症监护室(intensive care unit,ICU)中的重要性日益凸显。动态葡萄糖监...重症患者常因创伤、手术、应激、疾病等多种因素,导致患者血糖变异性升高。医务人员提高对重症患者血糖的精细化管理能力,对改善重症患者预后至关重要,血糖监测在重症监护室(intensive care unit,ICU)中的重要性日益凸显。动态葡萄糖监测(continuous glucose monitoring,CGM)是一种通过测定患者皮下组织间液葡萄糖浓度,间接反映患者血糖水平的监测技术,有助于掌握患者的整体血糖水平,辅助血糖管理。此项技术的问世,可以为重症患者及临床医师提供全面、连续、可靠的全天血糖数据,已在重症医学领域引起广泛重视。展开更多
Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave(EMW)absorbers.It would be promising to fabricate a hollow...Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave(EMW)absorbers.It would be promising to fabricate a hollow structured composite integrating multiple loss mechanisms(conduction,magnetic,and polarization losses)for excellent EMW absorption.Herein,a novel dielectric-magnetic compound of ZnO/Ni@C hollow microsphere was prepared through hydrothermal reactions followed by an in-situ chemical vapor deposition(CVD).In this ternary composite,abundant ZnO/Ni heterostructures formed the hollow microsphere skeletons and provided unique Schottky junctions,which endowed the composite with improved impedance matching and strong polarization loss.Meanwhile,the amorphouspolycrystalline carbon layer deposited on the surface of each microsphere enhanced the conduction and interfacial polarization losses.In addition,the magnetic Ni nanoparticles induced magnetic loss.Benefiting from the synergistic effect of the hollow structure and multiple loss mechanisms,the ternary composite exhibits an effective absorption bandwidth as wide as 6.55 GHz at a thickness of only 1.85 mm,accompanied by a minimum reflection loss of–39.8 dB.Besides,the radar cross-section and the electromagnetic field simulation further verify the superior EMW absorption performance of the composites.Our work provides a new reference for the fabrication of dielectric-magnetic ternary hollow microspheres as EMW absorbers with thin thickness and broad bandwidth.展开更多
基金supported by the National Natural Science Foundation of China[Grant Nos.52272288 and 51972039]the China Postdoctoral Science Foundation[No.2021M700658].
文摘The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms.Herein,the chiral CNCs are first synthesized on a threedimensional(3D)carbon foam and then combined with the FeNi/NiFe_(2)O_(4) nanoparticles to form a novel chiral-dielectric-magnetic trinity foam.The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss.The formation of the FeNi-carbon interfaces induces interfacial polarization loss,which is confirmed by the density functional theory calculations.Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects,which enhance the magnetic anisotropy and magnetic loss capability.Owing to the synergistic effect between dielectricity,chirality,and magnetism,the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth(EAB)of 14 GHz and a minimum reflection of loss less than-50 dB.More importantly,the C-band EAB of the foam is extended to 4 GHz,achieving the full C-band coverage.This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.
基金supported in part by the National Key Research and Development Program under Grant(2021YFB2900300)by the National Natural Science Foundation of China(NSFC)under Grants 61971127,61871122by the Southeast University-China Mobile Research Institute Joint Innovation Center,and by the Major Key Project of PCL(PCL2021A01-2).
文摘This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passive sensing scheme.The scheme is based on the radio frequency(RF)fingerprint learning of the RF radio unit(RRU)to build an RF fingerprint library of RRUs.The source RRU is identified by comparing the RF fingerprints carried by the signal at the receiver side.The receiver extracts the channel parameters from the signal and estimates the channel environment,thus locating the reflectors in the environment.The proposed scheme can effectively solve the problem of interference between signals in the same time-frequency domain but in different spatial domains when multiple RRUs jointly serve users in CF-RAN architecture.Simulation results show that the proposed passive ISAC scheme can effectively detect reflector location information in the environment without degrading the communication performance.
文摘重症患者常因创伤、手术、应激、疾病等多种因素,导致患者血糖变异性升高。医务人员提高对重症患者血糖的精细化管理能力,对改善重症患者预后至关重要,血糖监测在重症监护室(intensive care unit,ICU)中的重要性日益凸显。动态葡萄糖监测(continuous glucose monitoring,CGM)是一种通过测定患者皮下组织间液葡萄糖浓度,间接反映患者血糖水平的监测技术,有助于掌握患者的整体血糖水平,辅助血糖管理。此项技术的问世,可以为重症患者及临床医师提供全面、连续、可靠的全天血糖数据,已在重症医学领域引起广泛重视。
基金supported by the National Natural Science Foundation of China(Nos.52272288 and 51972039)the China Postdoctoral Science Foundation(No.2021M700658).
文摘Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave(EMW)absorbers.It would be promising to fabricate a hollow structured composite integrating multiple loss mechanisms(conduction,magnetic,and polarization losses)for excellent EMW absorption.Herein,a novel dielectric-magnetic compound of ZnO/Ni@C hollow microsphere was prepared through hydrothermal reactions followed by an in-situ chemical vapor deposition(CVD).In this ternary composite,abundant ZnO/Ni heterostructures formed the hollow microsphere skeletons and provided unique Schottky junctions,which endowed the composite with improved impedance matching and strong polarization loss.Meanwhile,the amorphouspolycrystalline carbon layer deposited on the surface of each microsphere enhanced the conduction and interfacial polarization losses.In addition,the magnetic Ni nanoparticles induced magnetic loss.Benefiting from the synergistic effect of the hollow structure and multiple loss mechanisms,the ternary composite exhibits an effective absorption bandwidth as wide as 6.55 GHz at a thickness of only 1.85 mm,accompanied by a minimum reflection loss of–39.8 dB.Besides,the radar cross-section and the electromagnetic field simulation further verify the superior EMW absorption performance of the composites.Our work provides a new reference for the fabrication of dielectric-magnetic ternary hollow microspheres as EMW absorbers with thin thickness and broad bandwidth.
