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Preparation of amidoxime-based PE/PP fibers for extraction of uranium from aqueous solution

Nuclear Science and Techniques 2019年第2期30卷 39-51页

作者： Xiao Xu Xiao-jun Ding jun-xuan ao Rong Li Zhe Xing Xi-Yan Liu Xiao-Jing Guo Guo-Zhong Wu Hong-Juan Ma Xiao-Yan Zhao School of Petrochemical Engineering Changzhou University Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

A novel amidoxime-based fibrous adsorbent,denoted as PE/PP-g-(PAAc-co-Pao), was prepared by preirradiation grafting of acrylic acid and acrylonitrile onto polyethylene-coated polypropylene skin-core(PE/PP)fibers using 60 Co γ-ray irradiation, followed by amidoximation. The original and modified PE/PP fibers were characterized by a series of characterization methods to demonstrate the attachment of amidoxime groups onto the PE/PP fibers. Breaking strength tests confirmed that the fibrous adsorbent could maintain good mechanical properties. The adsorption capacity of the PE/PP-g-(PAAc-coPao) fibers was investigated in simulated seawater with an initial uranium concentration of 330 μg/L. The uranium adsorption capacity was 2.27 mg/g-adsorbent after 24 h in simulated seawater, and the equilibrium data were well described by the Freundlich isotherm model. The PE/PP-g-(PAAc-co-Pao) adsorbent exhibited good regeneration and recyclability during five adsorption-desorption *** adsorption test was also performed in simulated radioactive effluents with uranium concentrations of 10 and100 μg/L. The effect of the pH value on the adsorption capacity was also studied. At a very low initial concentration 10 μg/L solution, the PE/PP-g-(PAAc-co-Pao)fiber could remove as much as 93.0% of the uranium, and up to 71.2% of the uranium in the simulated radioactive effluent. These results indicated that the PE/PP-g-(PAAcco-Pao) adsorbent could be used in radioactive effluents over a wide range of pH values. Therefore, the PE/PP-g-(PAAc-co-Pao) fibers, with their high uranium selectivity,good regeneration and recyclability,good mechanical properties, and low cost, are promising adsorbents for extracting uranium from aqueous solutions.

关键词： Amidoxime groups Pre-irradiation PEcoated PP skin-core fiber Adsorption Uranium

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Emerging progress: photochemical transformation of nitroso compounds

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Science China Chemistry 2025年第01期 118-133页

作者： Ze-Le Chen Qiang-Qiang Li Armido Studer jun xuan Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials School of Chemistry & Chemical Engineering Anhui University Organisch-Chemisches Institut Universitat Münster

Nitroso compounds have emerged as highly valuable reaction partners or reagents in organic synthesis due to their rich *** versatile profile of these compounds allows them to function as electrophiles, nucleophiles, diradicals, and radical acceptors in diverse transformations. In recent years, notable progress has been made in harnessing photochemical reactions with nitroso compounds to prepare N,O-containing structures using mild and eco-friendly conditions. Various nitroso compounds like nitrosoarenes, acyloxy nitroso compounds, N-nitrosoamines and nitrites have received significant attention for their ability to introduce NO moieties into complex molecules that are otherwise difficult to access. In this review, we provide an overview of the recent advancements in the visible light-induced conversion of nitroso compounds, with particular emphasis on their role as bifunctional reagents and acceptors of radicals, carbenes and nitrenes.

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Broadcast group-oriented encryption secure against chosen ciphertext attack

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Journal of Systems Engineering and Electronics 2007年第4期18卷 811-817页

作者： Ma Chunbo ao jun Li Jianhua School of Information Security Engineering Shanghai Jiaotong Univ. Shanghai 200030 P. R. China The State Key Laboratory of Information Security Beijing 100049 P. R. China State Key Laboratory for Radar Signal Processing Xidian Univ Xi'an 710071 P. R. China

A novel broadcast encryption scheme for group communication scenarios in distributed networks is presented. In the scheme, anyone is allowed to encrypt a message and distribute it to a designated group. Each member in the designated group has the ability to independently decrypt a ciphertext. In contrast to traditional broadcast encryption, all the valid receivers in the proposed scheme compose the designated group. To take advantage of this property, a tab for the group is set and the matching private key for each member is generated. In addition, before decrypting a ciphertext, anyone in the scheme can verify the ciphertext, to ensure that the ciphertext is correct. This property is very important for large-scale group communication, as the gateway can filter incorrect ciphertext and alleviate the receiver＇s workload. Finally, a proof in the random oracle model is given, to show that the proposed scheme is secure against the adaptively chosen ciphertext attack.

关键词： broadcast group-oriented encryption chosen ciphertext attack public verification

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Some New Observing Features of a Solar Radio Spectral Event on August 25,1999

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Chinese Physics Letters 2000年第11期17卷 850-852页

作者： XU Fu-Ying LIU Yu-Ying Yao Qi-jun FU Qi-jun MENG xuan WU Hong-ao Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008 Beijing Astronomical Observatory Chinese Academy of SciencesBeijing 100012 National Astronomical Observatories Chinese Academy of Sciences

A broadband solar radio type III burst was observed on August 25,1999 at Purple Mountain Observatory with waveband of 4.5-7.5 *** was also observed at Beijing Astronomical Observatory with waveband of 5.2-7.6 ***,it is the first common spectral event observed in *** type III bursts are gathered into more than 10 groups and drift in opposite directions,but the reverse drifting *** largest bandwidth of type III burst reaches≥3 GHz and may be the broadest bandwidth of the reverse type III burst ever observed up to the *** new observing characteristics of fine structures are found,for example,fiber-like,V-shaped and neck-ring-like ***,the neck-ring-like structure is probably first discovered in cm waveband and may be the evidence of twisted rope of magnetic lines.

关键词： Solar twisted shaped

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First principles study of Fenton reaction catalyzed by FeOCl:reaction mechanism and location of active site

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Rare Metals 2019年第8期38卷 783-792页

作者： xuan-xuan Ji Hai-Feng Wang Pei-jun Hu Key Laboratory for Advanced Materials Research Institute of Industrial Catalysis and Centre for Computational Chemistry School of Chemical and Molecular Engineering East China University of Science and Technology Shanghai 200237 China School of Chemistry and Chemical Engineering The Queen’s University of Belfast Belfast BT9 5AZ UK

Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 ***,the mechanism of Fenton reaction on FeOCl and the origin of high activity remain ***,by virtue of DFT+ U calculations,the H2 O2 decomposition and conversion mechanism on FeOCl(100)surface were systematically *** is found that on clean FeOCl(100)surface,the exposed[Fe^3+-Fe^3+]sites can hardly break O-O bond of H2 O2 into OH groups,but instead H2 O2 tends to dehydrogenate by the surface lattice O,resulting in a series of side reactions and final conversion into O2,while the left H atoms gradually saturate the surface lattice O and reduce Fe^3+ into Fe^2+.On fully H-covered FeOCl(100),H2O2 can efficiently dissociate at[Fe^2+-Fe^2+]sites into two OH,but OH binds with Fe^2+ so strongly that it cannot desorb as OH radical as easily as that on Fe^3+.Interestingly,FeOCl(100)tends to be partially protonated in the real acid solution,which,along with H2 O2 dehydrogenation,results in the formation of active unit [Fe^2+-Fe^3+].On[Fe^2+-Fe^3+]unit,H2 O2 can easily break its O-O bond and OH at Fe3+ can desorb as OH radical,while the other OH at Fe^2+ couples with the surface H into H2O and finish the catalytic *** comparison,Fe2 O3(012)cannot provide enough [Fe^2+-Fe^3+] active units due to the relative difficulty in H2 O2 dehydrogenation,which accounts for its inferior catalytic efficiency for Fenton reaction.

关键词： Fenton reaction FeOCl Density functional theory H2O2 Active site

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Designing electrolytes for lithium metal batteries with rational interface stability

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Rare Metals 2021年第2期40卷 243-245页

作者： Chen-xuan Xu Jian-jun Jiang School of Physics and Electronics Hunan UniversityChangsha410082China

Lithium(Li)-ion batteries(LIBs)have promoted the development of portable electronics and electric vehicles[1,2].However,with the rapid increase in energy demand,it is increasingly urgent to develop batteries with high energy density[3].Li metal batteries(LMBs)are considered as the"Holy Grail"which have attracted much attention due to the high theoretical capacity(3860 mAh·g^(-1))and low redox potential(-3.040 V *** standard hydrogen electrode)[4,5].

关键词： lithium rational interface

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Electrolytes speed up development of zinc batteries

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Rare Metals 2021年第4期40卷 749-751页

作者： Chen-xuan Xu Jian-jun Jiang School of Physics and Electronics Hunan UniversityChangsha 410082China

Zinc (Zn) batteries have attracted great attention since Zn anode is cost-effective and safe,and also exhibit high capacity and low *** effort has been made to achieve superior battery performance,i.e.,structural design of cathodes,optimizing electrolytes,and modification of Zn anode [1-3].Zn batteries can apply aqueous electrolytes and non-aqueous ***,both of them also suffer from some obstacles in the practical applications.

关键词： battery potential. Zinc

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Experimental Study of Operation Performance for Hydrocarbon Fuel Pump with Low Specific Speed

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Journal of Thermal Science 2017年第5期26卷 440-447页

作者： WU Xianyu YANG jun JIN xuan College of Aerospace Science and Engineering National Univ. of Defense Technology ChangSha 410073 China

In this paper, a small flow rate hydrocarbon turbine pump was used to pressurize the fuel supply system of scramjet engine. Some experiments were carried out to investigate the characteristics of turbine pump driven by nitrogen or combustion gas under different operating conditions. A experimental database with regard to the curves of the rotational speed, mass flow rate and net head with regard to centrifugal pump were plotted. These curves were represented as functions of the pressure and temperature at turbine inlet/outlet and the throttle diameter at downstream of centrifugal pump. A sensitivity study has been carried out based on design of experiments. The experimental was employed to analyze net head of centrifugal and throttle characteristics. The research results can accumulate foundations for the close loop control system of turbine pump.

关键词： expansion cycle scram jet hydrocarbon fuel turbo-pump operation performance

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Molecular understanding of cation effects on double layers and their significance to CO-CO dimerization

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National Science Review 2023年第9期10卷 125-135页

作者： Jia-Bo Le ao Chen Yongbo Kuang jun Cheng Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM College of Chemistry and Chemical EngineeringXiamen University Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)

Cation effects have been shown in numerous experiments to play a significant role in electro *** understand these effects at the molecular level,we systematically investigate the structures and capacitances of electric double layers with a variety of cations as counter charges at Pt(111)-COad/water interfaces with ab initio molecular *** is encouraging to find that the computed Helmholtz capacitances for different cations are in quantitative agreement with experiments,and that the trend of cation effects on capacitances shows clear correlation with the structures of interface cations of differing sizes and hydration *** importantly,we demonstrate the Helmholtz capacitance as the key descriptor for measuring the activity of CO-CO dimerization,the rate-determining step for C2+formation in electroreduction of CO and *** work provides atomistic insights into cation effects on electric double layers and electrocatalysis that are crucial for optimizing electrode and electrolyte materials.

关键词： cation effect electrocatalysis electric double layer CO-CO dimerization ab initio molecular dynamics

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The Early Permian Woniusi Flood Basalts from the Baoshan Terrane, SW China: Petrogenesis and Geodynamic Implications

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Acta Geologica Sinica(English Edition) 2020年第6期94卷 2091-2114页

作者： Cao jun ZHANG Gaizhi WANG xuan CHEN jun State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China Shandong Key Laboratory of Depositional Mineralization&Sedimentary Minerals Shandong University of Science and TechnologyQingdaoShandong 266590China School of Earth Sciences East China University of TechnologyNanchang 330013China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

The Woniusi flood basalts from the Baoshan terrane,SW China,represent a significant eruption of volcanic rocks which were linked to the Late Paleozoic rifting of the Cimmeria from the northern margin of East ***,the precise mechanism for the formation and propagation of the rifting is still in *** we report 40 Ar/39 Ar dating,whole-rock geochemistry,and Sr-Nd-Pb isotopes for the Woniusi basalts from the Baoshan terrane of SW China,with the aim of assessing if a mantle plume was related to the formation of the continent Cimmeria.40 Ar/39 Ar dating of the Woniusi basalts yielded ages of 279.3±1.1 Ma and 273.9±1.5 Ma,indicating they were emplaced during the Early ***-rock geochemistry shows that these basalts have subalkaline tholeiitic affinity,low Ti O2(1.2-2.2 wt%),and fractionated chondrite-normalized LREE and nearly flat HREE patterns[(La/Yb)N=2.86-5.77;(Dy/Yb)N=1.21-1.49]with noticeable negative Nb and Ta anomalies on the primitive mantle-normalized trace element ***ε(Nd)(t)values(-4.76 to+0.92)and high(206 Pb/204 Pb)i(18.40-18.66)along with partial melt modeling indicates that the basalts were likely derived from a sub-continental lithospheric mantle(SCLM)source metasomatized by subduction-related *** the basis of a similar emplacement age to the Panjal basalts and Qiangtang mafic dykes and flood basalts in the Himalayas,combined with a tectonic reconstruction of Gondwana in the Early Permian,we propose that the large-scale eruption of these basalts and dykes was related to an Early Permian mantle plume that possibly initiated the rifting on the northern margin of East Gondwana.

关键词： geochemistry flood basalts Early Permian Baoshan Gondwana

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