In order to improve the absorbing properties of M- type barium ferrite absorbing materials, M-type barium ferrite/graphene oxide composites with different graphene oxide contents were synthesized by the sol-gel autoco...In order to improve the absorbing properties of M- type barium ferrite absorbing materials, M-type barium ferrite/graphene oxide composites with different graphene oxide contents were synthesized by the sol-gel autocombustion method. X-ray diffraction （XRD）, a scanning electronic microscopy （ SEM ）, a physical properties measurement system （PPMS-9）, and a vector network analyzer were used to analyze their structure, surface morphology, magnetic and absorbing properties, respectively. The results show that the absorbing band of the composite absorbing material is widened and the absorbing strength is increased compared with the pure M-type barium ferrite. The sample with the content of doped graphene oxide of 3% has the minimum reflectivity at 10 to 18 GHz frequencies. Hence, the doped graphene oxide effectively improves the absorbing properties of M-type barium ferrite.展开更多
Graphene oxides(GOs) were synthesized via modified Hummers method, and were applied as adsorbents to remove radionuclides from large volumes of aqueous solutions. The single and competitive sorption of four radionucli...Graphene oxides(GOs) were synthesized via modified Hummers method, and were applied as adsorbents to remove radionuclides from large volumes of aqueous solutions. The single and competitive sorption of four radionuclides(i.e., U(VI), 152+154Eu(III), 85+89Sr(II) and 134Cs(I)) on the GOs from aqueous solutions were investigated as a function of p H, ionic strength and radionuclide initial concentrations using batch technique. The results showed that the GOs had much higher sorption capacity than many other contemporary materials, for the preconcentration of radionuclides from large volumes of aqueous solutions. The sorption of radionuclides on GOs obeyed the Langmuir model, and was mainly attributed to surface complexation via the coordination of radionuclides with the oxygen-containing functional groups on GO surfaces. The competitive sorption results indicated that the selectivity sorption capacities were U(VI)>Eu(III)>Sr(II)>Cs(I). The GOs are suitable materials for the efficient removal and preconcentration of radionuclides from aqueous solutions in nuclear waste management and environmental pollution cleanup.展开更多
A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz(THz) absorbers.We investigate the properties of the graphene metamaterial with diff...A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz(THz) absorbers.We investigate the properties of the graphene metamaterial with different interlayers in the 0–3 THz range.The simulation results show that the absorption rate reaches up to 99.9% at the frequency of 1.917 THz.Changing the period to 80 μm×18 μm can get a narrow-band high quality factor(Q) absorber.We present a novel theoretical interpretation based on the standing wave field theory,which shows that the coherent superposition of incident and reflection rays produces standing waves,and the field energy is localized inside the thick spacers and dissipates through the metal-planes.展开更多
基金The National Natural Science Foundation of China(No.51205282)
文摘In order to improve the absorbing properties of M- type barium ferrite absorbing materials, M-type barium ferrite/graphene oxide composites with different graphene oxide contents were synthesized by the sol-gel autocombustion method. X-ray diffraction （XRD）, a scanning electronic microscopy （ SEM ）, a physical properties measurement system （PPMS-9）, and a vector network analyzer were used to analyze their structure, surface morphology, magnetic and absorbing properties, respectively. The results show that the absorbing band of the composite absorbing material is widened and the absorbing strength is increased compared with the pure M-type barium ferrite. The sample with the content of doped graphene oxide of 3% has the minimum reflectivity at 10 to 18 GHz frequencies. Hence, the doped graphene oxide effectively improves the absorbing properties of M-type barium ferrite.
基金supported by the National Natural Science Foundation of China(21225730,91326202)the Fundamental Research Funds for the Central Universities+2 种基金the Jiangsu Provincial Key Laboratory of Radiation Medicine,Protectionthe Priority Academic Program Development of Jiangsu Higher Education InstitutionsMCTL Visiting Fellowship Program from Key Laboratory of Marine Chemistry Theory and Technology(Ocean University of China),Ministry of Education
文摘Graphene oxides(GOs) were synthesized via modified Hummers method, and were applied as adsorbents to remove radionuclides from large volumes of aqueous solutions. The single and competitive sorption of four radionuclides(i.e., U(VI), 152+154Eu(III), 85+89Sr(II) and 134Cs(I)) on the GOs from aqueous solutions were investigated as a function of p H, ionic strength and radionuclide initial concentrations using batch technique. The results showed that the GOs had much higher sorption capacity than many other contemporary materials, for the preconcentration of radionuclides from large volumes of aqueous solutions. The sorption of radionuclides on GOs obeyed the Langmuir model, and was mainly attributed to surface complexation via the coordination of radionuclides with the oxygen-containing functional groups on GO surfaces. The competitive sorption results indicated that the selectivity sorption capacities were U(VI)>Eu(III)>Sr(II)>Cs(I). The GOs are suitable materials for the efficient removal and preconcentration of radionuclides from aqueous solutions in nuclear waste management and environmental pollution cleanup.
基金supported by the National Natural Science Foundation of China(Nos.61205096 and 11364010)the Science Foundation of Education Department of Guangxi in China(No.200911LX17)
文摘A kind of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer is designed for terahertz(THz) absorbers.We investigate the properties of the graphene metamaterial with different interlayers in the 0–3 THz range.The simulation results show that the absorption rate reaches up to 99.9% at the frequency of 1.917 THz.Changing the period to 80 μm×18 μm can get a narrow-band high quality factor(Q) absorber.We present a novel theoretical interpretation based on the standing wave field theory,which shows that the coherent superposition of incident and reflection rays produces standing waves,and the field energy is localized inside the thick spacers and dissipates through the metal-planes.
