High efficient removal and recovery of uranium and thorium from nuclear waste solution are essential for environmental preservation and fuel recycle. A new polymer fiber adsorbent (UHMEPE-g-PAO fiber), prepared by ami...High efficient removal and recovery of uranium and thorium from nuclear waste solution are essential for environmental preservation and fuel recycle. A new polymer fiber adsorbent (UHMEPE-g-PAO fiber), prepared by amidoximation of grafted polyacrylonitrile onto Ultra High Molecular Weight Polyethylene (UHMWPE) fiber, was used to remove the uranyl and thorium ions from acid aqueous solutions and its performance was carefully investigated. It was found that uranyl ion can penetrate the fiber through the connected pore structures, forming (UO2) (R-C(NH2)-NO)2 chelates with the amidoxime groups within the fiber. Two amidoxime groups (U-N and U-Oeq) and two water molecules (U-Oeq2) are bound to uranyl ion in the fiber. On the contrary, thorium ions are adsorbed mainly on the fiber surface in the form of Th(OH)4 precipitate that blocks the entrance of Th4+ ion into fiber pores. The maximum included other two capacities of uranyl and thorium ions were estimated to be 262.01 mg/g and 160 mg/g at room temperature with pH 3.0, respectively. The results also indicate that the UHMWPE-g-PAO fiber has higher adsorption selectivity for uranyl ion than thorium ion. Uranium and thorium oxide particles were obtained as the ultimate product after sintering of the fiber adsorbent. This novel and environmentally friendly adsorption process is feasible to extract uranium or thorium from acidic aqueous solution.展开更多
In this paper,a simple theoretical model combining Monte Carlo simulation with the enthalpy method is provided to simulate the damage resistance of B4C/Si-sub mirror under X-ray free-electron laser irradiation.Two dif...In this paper,a simple theoretical model combining Monte Carlo simulation with the enthalpy method is provided to simulate the damage resistance of B4C/Si-sub mirror under X-ray free-electron laser irradiation.Two different damage mechanisms are found,dependent on the photon energy.The optimum B4C film thickness is determined by studying the dependence of the damage resistance on the film thickness.Based on the optimized film thickness,the damage thresholds are simulated at photon energy of 0.4-25 keV and a grazing incidence angle of 2 mrad.It is recommended that the energy range around the Si K-edge should be avoided for safety reasons.展开更多
The present study establishes a visualization method for the measurement of the distribution and localization of protein/peptide constituents within a single poly-lactide-co-glycolide(PLGA) microsphere using synchrotr...The present study establishes a visualization method for the measurement of the distribution and localization of protein/peptide constituents within a single poly-lactide-co-glycolide(PLGA) microsphere using synchrotron radiation–based Fourier-transform infrared spectromicroscopy(SR-FTIR).The representative infrared wavenumbers specific for protein/peptide(Exenatide) and excipient(PLGA) were identified and chemical maps at the single microsphere level were generated by measuring and plotting the intensity of these specific bands.For quantitative analysis of the distribution within microspheres,Matlab software was used to transform the map file into a 3D matrix and the matrix values specific for the drug and excipient were extracted.Comparison of the normalized SR-FTIR maps of PLGA and Exenatide indicated that PLGA was uniformly distributed,while Exenatide was relatively non-uniformly distributed in the microspheres.In conclusion,SR-FTIR is a rapid,nondestructive and sensitive detection technology to provide the distribution of chemical constituents and functional groups in microparticles and microspheres.展开更多
文摘High efficient removal and recovery of uranium and thorium from nuclear waste solution are essential for environmental preservation and fuel recycle. A new polymer fiber adsorbent (UHMEPE-g-PAO fiber), prepared by amidoximation of grafted polyacrylonitrile onto Ultra High Molecular Weight Polyethylene (UHMWPE) fiber, was used to remove the uranyl and thorium ions from acid aqueous solutions and its performance was carefully investigated. It was found that uranyl ion can penetrate the fiber through the connected pore structures, forming (UO2) (R-C(NH2)-NO)2 chelates with the amidoxime groups within the fiber. Two amidoxime groups (U-N and U-Oeq) and two water molecules (U-Oeq2) are bound to uranyl ion in the fiber. On the contrary, thorium ions are adsorbed mainly on the fiber surface in the form of Th(OH)4 precipitate that blocks the entrance of Th4+ ion into fiber pores. The maximum included other two capacities of uranyl and thorium ions were estimated to be 262.01 mg/g and 160 mg/g at room temperature with pH 3.0, respectively. The results also indicate that the UHMWPE-g-PAO fiber has higher adsorption selectivity for uranyl ion than thorium ion. Uranium and thorium oxide particles were obtained as the ultimate product after sintering of the fiber adsorbent. This novel and environmentally friendly adsorption process is feasible to extract uranium or thorium from acidic aqueous solution.
基金supported by the National Natural Science Foundation of China(NSFC)(No.11875203)。
文摘In this paper,a simple theoretical model combining Monte Carlo simulation with the enthalpy method is provided to simulate the damage resistance of B4C/Si-sub mirror under X-ray free-electron laser irradiation.Two different damage mechanisms are found,dependent on the photon energy.The optimum B4C film thickness is determined by studying the dependence of the damage resistance on the film thickness.Based on the optimized film thickness,the damage thresholds are simulated at photon energy of 0.4-25 keV and a grazing incidence angle of 2 mrad.It is recommended that the energy range around the Si K-edge should be avoided for safety reasons.
基金financial support from the National Natural Science Foundation of China (Nos.81273453 and 81430087)
文摘The present study establishes a visualization method for the measurement of the distribution and localization of protein/peptide constituents within a single poly-lactide-co-glycolide(PLGA) microsphere using synchrotron radiation–based Fourier-transform infrared spectromicroscopy(SR-FTIR).The representative infrared wavenumbers specific for protein/peptide(Exenatide) and excipient(PLGA) were identified and chemical maps at the single microsphere level were generated by measuring and plotting the intensity of these specific bands.For quantitative analysis of the distribution within microspheres,Matlab software was used to transform the map file into a 3D matrix and the matrix values specific for the drug and excipient were extracted.Comparison of the normalized SR-FTIR maps of PLGA and Exenatide indicated that PLGA was uniformly distributed,while Exenatide was relatively non-uniformly distributed in the microspheres.In conclusion,SR-FTIR is a rapid,nondestructive and sensitive detection technology to provide the distribution of chemical constituents and functional groups in microparticles and microspheres.
