The reasonable design of the composition of the composite materials is of great significance to optimized the electromagnetic(EM)wave absorption performance.Herein,the Ni/NiO@C hybrid composites with tunable Ni propor...The reasonable design of the composition of the composite materials is of great significance to optimized the electromagnetic(EM)wave absorption performance.Herein,the Ni/NiO@C hybrid composites with tunable Ni proportion were successfully synthesized through a two-step process.With the assistance of X-ray diffraction with refinement treatment,the specific proportion of Ni of as-obtained hybrid composites could be obtained.Employing controlling calcination time to adjust the Ni content of Ni/NiO@C hybrid composites,it has been found that the composite carbonized at 500℃exhibited remarkable EM wave absorption with the minimum reflection loss(RLmin)of-49.1 dB at 4.9 mm and the widest effective absorption bandwidth(EABmax)of 4.56 GHz at 2.1 mm.Moreover,by adjusting the Ni source,the optimal EM wave absorption performance could be achieved.Results illustrated that the N3PC with the Ni proportion of 13.17%showed the RLm inas low as-51.1 dB at 2.4 mm and the EABmax was 5.12 GHz at 2.7 mm.It is worth noting that this work demonstrates the relevance of the composition and EM wave absorption performance of hybrid composites,which offers a feasible reference for the absorption mechanism of absorber.展开更多
Under the theory structure of compressive sensing （CS）, an underdetermined equation is deduced for describing the discrete solution of the electromagnetic integral equation of body of revolution （BOR）, which will ...Under the theory structure of compressive sensing （CS）, an underdetermined equation is deduced for describing the discrete solution of the electromagnetic integral equation of body of revolution （BOR）, which will result in a small-scale impedance matrix. In the new linear equation system, the small-scale impedance matrix can be regarded as the measurement matrix in CS, while the excited vector is the measurement of unknown currents. Instead of solving dense full rank matrix equations by the iterative method, with suitable sparse representation, for unknown currents on the surface of BOR, the entire current can be accurately obtained by reconstructed algorithms in CS for small-scale undetermined equations. Numerical results show that the proposed method can greatly improve the computgtional efficiency and can decrease memory consumed.展开更多
This study introduces a simple and cost-effective approach for modifying large organic surfaces,facilitating robust adhesion between Au films and polymethyl methacrylate(PMMA)while retaining transparency to visible li...This study introduces a simple and cost-effective approach for modifying large organic surfaces,facilitating robust adhesion between Au films and polymethyl methacrylate(PMMA)while retaining transparency to visible light and effectively shielding against electromagnetic interference(EMI).The proposed surface modification method employs a cheap low-power conventional UV lamp to illuminate organic surfaces in an open environment,rending it convenient and applicable for surfaces ranging from small to massive,irrespective of size,shape and location.By subjecting transparent PMMA glass to a brief 20–30 min exposure to a 36 W UV lamp positioned 5 cm away from the sample surface,the PMMA surface is dramatically modified and the surface is turned from hydrophobic to hydrophilic,establishing a strong adhesion between PMMA and Au films.The resulting Au/PMMA glass exhibits remarkable transparency about 70%within the visible light spectrum,coupled with an impressive EMI shielding efficiency that surpasses 20 dB across a broad range of electromagnetic wavebands,encompassing the S,C,X and Ku bands that correspond to the wave frequencies of major electromagnetic pollution and crucial applications of 5G communication,credit card validation,radar systems,traffic control,etc.Various characterizations have been conducted,elucidating the underlying mechanisms.This study presents an important advancement,and the accessible and scalable nature of the large-scalable surface modification method has far-reaching implications across numerous industrial sectors and applications,in addition to transparent EMI shielding Au/PMMA glasses.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51407134,51801001 and 51801108)Natural Science Foundation of Shandong Province(No.ZR2019YQ24)+5 种基金China Postdoctoral Science Foundation(No.2016M590619,No.2016M601878)Provincial Key Research and Development Program of Shaanxi(No.2019GY-197)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)the support from The Thousand Talents PlanThe World-Class University and DisciplineThe Taishan Scholar’s Advantageous and Distinctive Discipline Program of Shandong ProvinceThe World-Class Discipline Program of Shandong Province。
文摘The reasonable design of the composition of the composite materials is of great significance to optimized the electromagnetic(EM)wave absorption performance.Herein,the Ni/NiO@C hybrid composites with tunable Ni proportion were successfully synthesized through a two-step process.With the assistance of X-ray diffraction with refinement treatment,the specific proportion of Ni of as-obtained hybrid composites could be obtained.Employing controlling calcination time to adjust the Ni content of Ni/NiO@C hybrid composites,it has been found that the composite carbonized at 500℃exhibited remarkable EM wave absorption with the minimum reflection loss(RLmin)of-49.1 dB at 4.9 mm and the widest effective absorption bandwidth(EABmax)of 4.56 GHz at 2.1 mm.Moreover,by adjusting the Ni source,the optimal EM wave absorption performance could be achieved.Results illustrated that the N3PC with the Ni proportion of 13.17%showed the RLm inas low as-51.1 dB at 2.4 mm and the EABmax was 5.12 GHz at 2.7 mm.It is worth noting that this work demonstrates the relevance of the composition and EM wave absorption performance of hybrid composites,which offers a feasible reference for the absorption mechanism of absorber.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51477039 and 51207041the Program of Hefei Normal University under Grant Nos 2014136KJA04 and 2015TD01the Key Project of Provincial Natural Science Research of University of Anhui Province of China under Grant No KJ2015A174
文摘Under the theory structure of compressive sensing （CS）, an underdetermined equation is deduced for describing the discrete solution of the electromagnetic integral equation of body of revolution （BOR）, which will result in a small-scale impedance matrix. In the new linear equation system, the small-scale impedance matrix can be regarded as the measurement matrix in CS, while the excited vector is the measurement of unknown currents. Instead of solving dense full rank matrix equations by the iterative method, with suitable sparse representation, for unknown currents on the surface of BOR, the entire current can be accurately obtained by reconstructed algorithms in CS for small-scale undetermined equations. Numerical results show that the proposed method can greatly improve the computgtional efficiency and can decrease memory consumed.
基金financial supports from the National Youth Science Funds of China(Grant No.52302172)The State Key Program of National Natural Science of China(Grant No.52032004),。
文摘This study introduces a simple and cost-effective approach for modifying large organic surfaces,facilitating robust adhesion between Au films and polymethyl methacrylate(PMMA)while retaining transparency to visible light and effectively shielding against electromagnetic interference(EMI).The proposed surface modification method employs a cheap low-power conventional UV lamp to illuminate organic surfaces in an open environment,rending it convenient and applicable for surfaces ranging from small to massive,irrespective of size,shape and location.By subjecting transparent PMMA glass to a brief 20–30 min exposure to a 36 W UV lamp positioned 5 cm away from the sample surface,the PMMA surface is dramatically modified and the surface is turned from hydrophobic to hydrophilic,establishing a strong adhesion between PMMA and Au films.The resulting Au/PMMA glass exhibits remarkable transparency about 70%within the visible light spectrum,coupled with an impressive EMI shielding efficiency that surpasses 20 dB across a broad range of electromagnetic wavebands,encompassing the S,C,X and Ku bands that correspond to the wave frequencies of major electromagnetic pollution and crucial applications of 5G communication,credit card validation,radar systems,traffic control,etc.Various characterizations have been conducted,elucidating the underlying mechanisms.This study presents an important advancement,and the accessible and scalable nature of the large-scalable surface modification method has far-reaching implications across numerous industrial sectors and applications,in addition to transparent EMI shielding Au/PMMA glasses.
