In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiat...In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced.展开更多
A cobalt-based metal-organic framework[Co_(3)(L)_(2)(1,4-bib)_(4)]·4H_(2)O(Co-MOF)was prepared using 5-[(4-carboxyphenoxy)methyl]isophthalic acid(H_(3)L)and 1,4-bis(1H-imidazol-1-yl)benzene(1,4-bib)as ligands.The...A cobalt-based metal-organic framework[Co_(3)(L)_(2)(1,4-bib)_(4)]·4H_(2)O(Co-MOF)was prepared using 5-[(4-carboxyphenoxy)methyl]isophthalic acid(H_(3)L)and 1,4-bis(1H-imidazol-1-yl)benzene(1,4-bib)as ligands.Then,an electrochemical sensor modified with Co-MOF on a glassy carbon electrode(Co-MOF@GCE)was constructed for detecting Cd^(2+)and Pb^(2+)in aqueous solutions.The sensor exhibited a linear range of 1.0-16.0µmol·L^(-1)with a detection limit(LOD)of 4.609 nmol·L^(-1)for Cd^(2+),and 0.5-10.0µmol·L^(-1)with an LOD of 1.307 nmol·L^(-1)for Pb^(2+).Simultaneous detection of both ions within 0.5-7.0µmol·L^(-1)achieved LOD values of 0.47 nmol·L^(-1)(Cd^(2+))and 0.008 nmol·L^(-1)(Pb^(2+)),respectively.Analysis of real water samples(tap water,mineral water,and river water)yielded recoveries of 95%-105%,validating practical applicability.Density functional theory(DFT)calculations reveal that synergistic interactions between cobalt centers and N/O atoms enhance adsorption and electron-transfer efficiency.CCDC:2160744.展开更多
A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric anal...A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscope(TEM),powder X-raydiffraction(XRD)and X-rayphotoelectron spectroscopy(XPS)were employed to characterize the prepared 3D graphene/MgO composite.The adsorption performance of some metal ions on 3D graphene/MgO was investigated.The results showed that the adsorption capacity was greater than 3D graphene and the maximum adsorption capacity at 25℃was found to be 358.96 mg/g,388.4 mg/g and 169.8 mg/g for Pb^2+,Cd^2+and Cu^2+,respectively.The adsorption kinetic conformed to the pseudo-second-order kinetic model and the adsorption isotherm was well described by Langmuir model.The thermodynamic constants revealed that the sorption process was endothermic and spontaneous in nature.Based on the results of the removal of heavy metal ions from metal smelting wastewater,it can be concluded that the prepared 3D graphene/MgO composite is an effective and potential adsorbent.展开更多
The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) tri...The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.展开更多
基金Supported by National Key R&D Program of China(2019YFA0405400)。
文摘In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced.
文摘A cobalt-based metal-organic framework[Co_(3)(L)_(2)(1,4-bib)_(4)]·4H_(2)O(Co-MOF)was prepared using 5-[(4-carboxyphenoxy)methyl]isophthalic acid(H_(3)L)and 1,4-bis(1H-imidazol-1-yl)benzene(1,4-bib)as ligands.Then,an electrochemical sensor modified with Co-MOF on a glassy carbon electrode(Co-MOF@GCE)was constructed for detecting Cd^(2+)and Pb^(2+)in aqueous solutions.The sensor exhibited a linear range of 1.0-16.0µmol·L^(-1)with a detection limit(LOD)of 4.609 nmol·L^(-1)for Cd^(2+),and 0.5-10.0µmol·L^(-1)with an LOD of 1.307 nmol·L^(-1)for Pb^(2+).Simultaneous detection of both ions within 0.5-7.0µmol·L^(-1)achieved LOD values of 0.47 nmol·L^(-1)(Cd^(2+))and 0.008 nmol·L^(-1)(Pb^(2+)),respectively.Analysis of real water samples(tap water,mineral water,and river water)yielded recoveries of 95%-105%,validating practical applicability.Density functional theory(DFT)calculations reveal that synergistic interactions between cobalt centers and N/O atoms enhance adsorption and electron-transfer efficiency.CCDC:2160744.
基金Projects(21571191,51674292) supported by the National Natural Science Foundation of ChinaProject(2016JJ1023) supported by the Natural Science Foundation of Hunan Province,ChinaProject(2018TP1003) supported by the Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety,China
文摘A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscope(TEM),powder X-raydiffraction(XRD)and X-rayphotoelectron spectroscopy(XPS)were employed to characterize the prepared 3D graphene/MgO composite.The adsorption performance of some metal ions on 3D graphene/MgO was investigated.The results showed that the adsorption capacity was greater than 3D graphene and the maximum adsorption capacity at 25℃was found to be 358.96 mg/g,388.4 mg/g and 169.8 mg/g for Pb^2+,Cd^2+and Cu^2+,respectively.The adsorption kinetic conformed to the pseudo-second-order kinetic model and the adsorption isotherm was well described by Langmuir model.The thermodynamic constants revealed that the sorption process was endothermic and spontaneous in nature.Based on the results of the removal of heavy metal ions from metal smelting wastewater,it can be concluded that the prepared 3D graphene/MgO composite is an effective and potential adsorbent.
基金Project(2012CB722803)supported by the Key Project of National Basic Research and Development Program of ChinaProject(U1202271)supported by the National Natural Science Foundation of ChinaProject(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of China
文摘The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.
