Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship betw...Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.展开更多
In field experiments, the effect of nitrogen application on 15N absorption and distribution of Longjing 31 and Kongyu 131 rice varieties was studied by ^15N isotopic trace technique. The results showed that nitrogen a...In field experiments, the effect of nitrogen application on 15N absorption and distribution of Longjing 31 and Kongyu 131 rice varieties was studied by ^15N isotopic trace technique. The results showed that nitrogen absorbed by rice plant is the most in the early plant growth, and ^15N accumulation of Longjing 31 grains are higher than Kongyu 131, but stem organ is the opposite; the realtocation and trans- fer efficiency of nitrogen absorbed by rice have an important role to the increasing of Longjing 31 output.展开更多
基金supported by the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.
基金Supported by Major Program of Scientific and Technological Bureau of Heilongjiang Province(GA06C101)Heilongjiang Postdoctoral Fund(LBH-Z13189)Heilongjiang Scientific and Technological Innovation Program(CX2012Z13)~~
文摘In field experiments, the effect of nitrogen application on 15N absorption and distribution of Longjing 31 and Kongyu 131 rice varieties was studied by ^15N isotopic trace technique. The results showed that nitrogen absorbed by rice plant is the most in the early plant growth, and ^15N accumulation of Longjing 31 grains are higher than Kongyu 131, but stem organ is the opposite; the realtocation and trans- fer efficiency of nitrogen absorbed by rice have an important role to the increasing of Longjing 31 output.
