In this paper, we present an efficient method to obtain absorbers with broadened operating frequency bands. They are accomplished by using conventional magnetic absorbing materials （MAMs） in the forms of array and m...In this paper, we present an efficient method to obtain absorbers with broadened operating frequency bands. They are accomplished by using conventional magnetic absorbing materials （MAMs） in the forms of array and mesh structures, which are similar to those in the case of a frequency selective surface. The proposed approach is verified not only by simulations but also by experimental results under the normal incidence at microwave frequencies. Moreover, the wideband absorber is lighter than the conventional magnetic absorber. These results indicate that our proposed absorbing structures can be used for designing good electromagnetic absorbers.展开更多
A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-r...A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2-18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.展开更多
A novel method was proposed for the in situ synthesis of magnetite-containing mesoporous silica SBA- 16 via a sol-gel process coupled with precipitation and oxidation. The effect of the added amounts of reactants on t...A novel method was proposed for the in situ synthesis of magnetite-containing mesoporous silica SBA- 16 via a sol-gel process coupled with precipitation and oxidation. The effect of the added amounts of reactants on the mesostructural and magnetic properties of the magnetic mesoporous silica was inves- tigated, It was determined that the synthesized magnetic mesoporous silica with a total pore volume of 0.64-0.96 cm3/g and an average pore diameter of 4.0-14,9 nm had a relatively high saturation mag- netization value （1.11-5.77 emu/g） and a large surface area （258-747 m2/g）, Lysozyme was chosen as a model protein to test the performance of the magnetic mesoporous silica as a protein adsorbent, The high adsorption capacity （up to 212 mg/g） suggested a promising future as bimolecular hosts for the magnetic mesoporous silica.展开更多
The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to unders...The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to understand the kicker impedance before its installation into the tunnel. Conventional and improved wire methods are employed in the impedance measurement. The experimental results for the kicker impedance are explained by comparison with simulation using CST PARTICLE STUDIO. The simulation and measurement results confirm that the window-frame ferrite geometry and the end plate are the important structures causing coupling impedance. It is proved in the measurements that the mismatching from the power form network to the kicker leads to a serious oscillation sideband of the longitudinal and vertical impedance and the oscillation can be reduced by ferrite absorbing material.展开更多
基金Project supported by the Aeronautical Science Foundation of China (Grant No. 2011ZF88013)
文摘In this paper, we present an efficient method to obtain absorbers with broadened operating frequency bands. They are accomplished by using conventional magnetic absorbing materials （MAMs） in the forms of array and mesh structures, which are similar to those in the case of a frequency selective surface. The proposed approach is verified not only by simulations but also by experimental results under the normal incidence at microwave frequencies. Moreover, the wideband absorber is lighter than the conventional magnetic absorber. These results indicate that our proposed absorbing structures can be used for designing good electromagnetic absorbers.
文摘A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2-18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.
基金support of the National Natural Science Foundation of China (Grant Nos.20476050, 20490200 and 20525622)National Basic Research Program (2007CB714302)
文摘A novel method was proposed for the in situ synthesis of magnetite-containing mesoporous silica SBA- 16 via a sol-gel process coupled with precipitation and oxidation. The effect of the added amounts of reactants on the mesostructural and magnetic properties of the magnetic mesoporous silica was inves- tigated, It was determined that the synthesized magnetic mesoporous silica with a total pore volume of 0.64-0.96 cm3/g and an average pore diameter of 4.0-14,9 nm had a relatively high saturation mag- netization value （1.11-5.77 emu/g） and a large surface area （258-747 m2/g）, Lysozyme was chosen as a model protein to test the performance of the magnetic mesoporous silica as a protein adsorbent, The high adsorption capacity （up to 212 mg/g） suggested a promising future as bimolecular hosts for the magnetic mesoporous silica.
基金Supported by National Natural Science Foundation of China(11175193,11275221)
文摘The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to understand the kicker impedance before its installation into the tunnel. Conventional and improved wire methods are employed in the impedance measurement. The experimental results for the kicker impedance are explained by comparison with simulation using CST PARTICLE STUDIO. The simulation and measurement results confirm that the window-frame ferrite geometry and the end plate are the important structures causing coupling impedance. It is proved in the measurements that the mismatching from the power form network to the kicker leads to a serious oscillation sideband of the longitudinal and vertical impedance and the oscillation can be reduced by ferrite absorbing material.
