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Positron annihilation study of defect formation and evolution in matrix graphite under He ion irradiation

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Nuclear Science and Techniques 2025年第1期36卷 13-21页

作者： Hong-Xia Xu jian-Dang liu Bang-Jiao Ye Zi-Wen Pan jun Lin jin-Liang song jian-Qing Cao Chao Yan Ying-Ping Hao jin-Xing Cheng Qing-Bo Wang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai 200025China Beijing Institute of High Technology Beijing 100094China

The stability of matrix graphite under neutron irradiation and in corrosive environments is crucial for the safe operation of molten salt reactors(MSRs).Raman spectroscopy and a slow positron beam were employed to investigate the effects of He ion irradiation fluences and subsequent annealing on the microstructure and defects of the matrix *** ions with 500 keV energy and fluences ranging from 1.1×10^(15)ions∕cm^(2)to 3.5×10^(17)ions∕cm^(2)were used to simulate neutron irradiation at 300 *** samples with an irradiation fluence of 3.5×10^(16)ions∕cm^(2)were subjected to isochronal annealing at different temperatures(573 K,873 K and 1173 K)for 3 *** Raman results revealed that the D peak gradually increased,whereas the intrinsic G peak decreased with increasing irradiation *** the same irradiation fluence,the D peak gradually decreased,whereas the intrinsic G peak increased with increasing annealing *** positron beam analysis demonstrated that the density or size of irradiation defects(vacancy type)increased with higher irradiation fluence,but decreased rapidly with increasing annealing *** Raman spectral analysis of sample cross sections subjected to high irradiation fluences revealed the emergence of amorphization precisely at the depth where ion damage was most pronounced,whereas the surface retained its crystalline *** and positron annihilation analyses indicated that the matrix graphite exhibited good irradiation resistance to He ions at 300 ***,vacancy-type defects induced by He ion irradiation exhibit poor thermal stability and can be easily removed during annealing.

关键词： Graphite Positron annihilation Irradiation Raman spectrum

The GECAM ground search system for gamma-ray transients

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Science China(Physics,Mechanics & Astronomy) 2025年第3期68卷 161-174页

作者： Ce Cai Yan-Qiu Zhang Shao-Lin Xiong Ping Wang jian-Hui Li Xiao-Bo Li Cheng-Kui Li Yue Huang Shi-Jie Zheng Li-Ming song Shuo Xiao Qi-Bin Yi Yi zhao Sheng-Lun Xie Rui Qiao Yan-Qi Du Zhi-Wei Guo Wang-Chen Xue Chao Zheng Jia-Cong liu Chen-Wei Wang Wen-jun Tan Yue Wang jin-Peng Zhang Chao-Yang Li Guo-Ying zhao Xiao-Yun zhao Xiao-Lu Zhang Zhen Zhang Wen-Xi Peng Xiang Ma jing-Yan Shi Dong-Ya Guo jin Wang Xin-Qiao Li Xiang-Yang Wen Zheng-Hua An Fan Zhang College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal UniversityShijiazhuang050024China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China University of Chinese Academy of Sciences Beijing100049China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang550001China School of Physics and Optoelectronics Xiangtan UniversityXiangtan411105China School of Computer and Information Dezhou UniversityDezhou253023China Institute of Astrophysics Central China Normal UniversityWuhan430079China

In the era of time-domain,multi-messenger astronomy,the detection of transient events on the high-energy electromagnetic sky has become more important than *** gravitational wave high-energy electromagnetic counterpart all-sky monitor(GECAM)is a dedicated mission to monitor gamma-ray transients,launched in December,2020.A real-time on-board trigger and location software,using the traditional signal-to-noise ratio(SNR)method for blind search,is constrained to relatively bright signals due to the limitations in on-board computing resources and the need for real-time *** this work,we developed a ground-based pipeline for GECAM to search for various transients,especially for weak bursts missed by on-board *** pipeline includes both automatic and manual mode,offering options for blind search and targeted *** targeted search is specifically designed to search for interesting weak bursts,such as gravitational wave-associated gamma-ray bursts(GRBs).From the ground search of the data in the first year,GECAM has been triggered by 54 GRBs and other transients,including soft gamma-ray repeaters,X-ray binaries,solar flares,terrestrial gamma-ray *** report the properties of each type of triggers,such as trigger time and light *** this search pipeline and assuming a soft Band spectrum,the GRB detection sensitivity of GECAM is increased to about 1.1×10^(-8)erg cm^(-2)s^(-1)(10-1000 ke V,burst duration of 20 s).These results demonstrate that the GECAM ground search system(both blind search and targeted search)is a versatile pipeline to recover true astrophysical signals which were too weak to be found in the on-board search.

关键词： gamma-ray sources gravitational waves data analysis gamma-ray telescopes

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Corrosion Behavior of Cr Micro-alloyed Corrosion-resistant Rebar in Neutral Cl^--containing Environment

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Journal of Iron and Steel Research International 2016年第6期23卷 608-617页

作者： Dan song Wei SUN jin-yang jianG Han MA jian-chun ZHANG zhao-jun CHENG School of Material Science and Engineering Southeast University Nantong Ocean and Coastal Engineering Research Institute Hohai University College of Mechanics and Materials Hohai University jiangsu Shagang Group Co. Ltd.

A new low-cost corrosion-resistant rebar（HRB400R）was designed and fabricated by Cr *** HRB400 Rrebar had uniform distribution of Cr element in ferrite *** corrosion behavior of the rebar in the neutral Cl^--containing environment was studied systematically,and the improved corrosion resistance of the HRB400 Rrebar was *** to the corrosion-morphology observation and electrochemical monitoring during the constant immersion corrosion in the 3.5mass% NaCl solution,the HRB400 Rrebar presented alleviated corrosion damage,nobler Ecorr,lower Icorr,and larger Rtvalues,and these phenomena were more remarkable in the initial corrosion *** elevated electrode potential of the rebar,caused by the solid-solution of Cr micro-alloying in the ferrite grains,was the key to the corrosion-resistance *** HRB400 Rrebar also presented much lower mass-loss rate in the salt spray corrosion *** the elevated corrosion resistance of the matrix,the doping and enrichment of Cr element in the rust layer was another factor for the higher corrosion resistance,which retarded the penetration of aggressive medium through the rust layer.

关键词： alloyed systematically ferrite doping spray alloying grains immersion remarkable FeOOH

Role of cerium dopants in MoVNbo multi-metal oxide catalysts for selective oxidation of ethane

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Journal of Rare Earths 2022年第5期40卷 753-762,I0003页

作者： Baohua liu Liang Yan Huahua zhao jian Yang jun zhao Huanling song Lingjun Chou State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Suzhou Research Institute of LICP Chinese Academy of SciencesSuzhou 215123China

The effect of Ce on the structure of MoVNbCeO multi-metal oxide catalysts and the performance of ethane selective oxidation was *** multi-metal oxide catalysts with superior oxidizability exhibit high catalytic activity,and vanadium acts as the active center for ethane oxidation *** improved catalytic activity is related to the increased V^(5+) content on the catalyst surface,which results from the enhanced transformation of the electrons between V and ***,Ce effectively promotes oxygen adsorption,activation,and *** the presence of Ce can also prevent MoO_(3) formation and stabilize the Mo_(5)O_(14)-like *** addition,the catalyst with a moderate amount of Ce exhibits outstanding catalytic ***,the MVN-Ce catalyst with a Ce/V ratio of 0.1 exhibits the best performance:the total selectivity of the catalyst toward C_(2)H_(4) and CH_(3) COOH is the highest(72%) at the ethane conversion of 31%.Therefore,MoVNbCeO multi-metal oxides are promising candidates for selective oxidation.

关键词： Ethane oxidation Redox Mo5O14 Ce Active oxygen Rare earths

Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

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Defence Technology（防务技术） 2024年第4期34卷 217-224页

作者： Rui zhao jian Zheng jin Guo Yunbo Shi Hengzhen Feng jun Tang jun liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051ShanxiChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped *** effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and *** target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent *** proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k *** the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target *** results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.

关键词： Star-shaped metamaterials Broadband Vibration attenuation Low-frequency ultrasound vibration Transmission loss

A method and results of color calibration for the Chang'e-3 terrain camera and panoramic camera

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Research in Astronomy and Astrophysics 2014年第12期14卷 1557-1566页

作者： Xin Ren chun-Lai Li jian-jun liu Fen-Fei Wang jian-Feng Yang En-Hai liu Bin Xue Ru-jin zhao Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of Sciences Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Institute of Optics and Electronics Chinese Academy of Sciences

The terrain camera （TCAM） and panoramic camera （PCAM） are two of the major scientific payloads installed on the lander and rover of the Chang＇e 3 mission re- spectively. They both use a Bayer color filter array covering CMOS sensor to capture color images of the Moon＇s surface. RGB values of the original images are related to these two kinds of cameras. There is an obvious color difference compared with human visual perception. This paper follows standards published by the International Commission on Illumination to establish a color correction model, designs the ground calibration experiment and obtains the color correction coefficient. The image qual- ity has been significantly improved and there is no obvious color difference in the corrected images. Ground experimental results show that：（1） Compared with uncor- rected images, the average color difference of TCAM is 4.30, which has been reduced by 62.1%. （2） The average color differences of the left and right cameras in PCAM are 4.14 and 4.16, which have been reduced by 68.3% and 67.6% respectively.

关键词： Moon -- methods: data analysis -- techniques: image processing

Laboratory-scale investigation of response characteristics of liquid-filled rock joints with different joint inclinations under dynamic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第2期14卷 396-406页

作者： jin Huang Xiaoli liu Danqing song jian zhao Enzhi Wang jianmin Zhang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China Department of Civil Engineering Monash UniversityClaytonVIC3800Australia

In underground rock engineering,water-bearing faults may be subjected to dynamic loading,resulting in the coupling of hydraulic and dynamic *** the interaction mechanism between the stress waves induced by dynamic loadings and liquid-filled rock joints is therefore *** this study,an auxiliary device for simulating the liquid-filled layer was developed to analyze the dynamic response characteristics of liquid-filled rock joints in *** and polymethyl methacrylate(PMMA)specimens were chosen for testing,and high-amplitude shock waves induced by a split Hopkinson pressure bar(SHPB)were used to produce dynamic *** loading tests were conducted on liquid-filled rock joints with different joint *** energy propagation coefficient and peak liquid pressure were proposed to investigate the energy propagation and attenuation of waves propagating across the joints,as well as the dynamic response characteristics of the liquid in the liquid-filled rock *** the inclination angle range considered herein,the experimental results showed that the energy propagation coefficient gently diminished with increasing joint inclination,and smaller coefficient values were obtained for granite specimens compared with PMMA *** peak liquid pressure exhibited a gradually decreasing trend with increasing joint inclination,and the peak pressure for granite specimens was slightly higher than that for PMMA ***,this paper may provide a considerably better method for studying liquid-filled rock joints at the laboratory scale,and serves as a guide for interpreting the underlying mechanisms for interactions between stress waves and liquid-filled rock joints.

关键词： Liquid-filled rock joint Stress wave Laboratory investigation Wave propagation characteristics Liquid dynamic response

Zedoarondiol Inhibits Neovascularization in Atherosclerotic Plaques of ApoE-/- Mice by Reducing Platelet Exosomes-Derived MiR-let-7a

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Chinese Journal of Integrative Medicine 2025年第3期 228-239页

作者： XIE Bei-li song Bo-ce liu Ming-wang WEN Wei YAN Yu-xin GAO Meng-jie jianG Lu-lian jin Zhi-die YANG Lin liu jian-gang SHI Da-zhuo zhao Fu-hai Cardiovascular Department Xiyuan Hospital China Academy of Chinese Medical Sciences Cardiovascular Department Beijing Hospital of Integrated Chinese and Western Medicine Graduate School of Beijing University of Chinese Medicine National Clinical Research Center for Chinese Medicine Cardiology

Objective: To investigate the effect of zedoarondiol on neovascularization of atherosclerotic（AS） plaque by exosomes experiment. Methods: ApoE-/-mice were fed with high-fat diet to establish AS model and treated with high-and low-dose（10, 5 mg/kg daily） of zedoarondiol, respectively. After 14 weeks, the expressions of anti-angiogenic protein thrombospondin 1（THBS-1） and its receptor CD36 in plaques, as well as platelet activation rate and exosome-derived miR-let-7a were detected. Then, zedoarondiol was used to intervene in platelets in vitro, and miR-let-7a was detected in platelet-derived exosomes（Pexo）. Finally, human umbilical vein endothelial cells（HUVECs） were transfected with miR-let-7a mimics and treated with Pexo to observe the effect of miR-let-7a in Pexo on tube formation. Results: Animal experiments showed that after treating with zedoarondiol, the neovascularization density in plaques of AS mice was significantly reduced,THBS-1 and CD36 increased, the platelet activation rate was markedly reduced, and the miR-let-7a level in Pexo was reduced（P<0.01）. In vitro experiments, the platelet activation rate and miR-let-7a levels in Pexo were significantly reduced after zedoarondiol's intervention. Cell experiments showed that after Pexo's intervention,the tube length increased, and the transfection of miR-let-7a minics further increased the tube length of cells,while reducing the expressions of THBS-1 and CD36. Conclusion: Zedoarondiol has the effect of inhibiting neovascularization within plaque in AS mice, and its mechanism may be potentially related to inhibiting platelet activation and reducing the Pexo-derived miRNA-let-7a level.

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Recent advances in vacancy engineering for reliable lithiumsulfur batteries

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Rare Metals 2024年第2期43卷 455-477页

作者： Wen-Dong liu Xiao Tang jun-An Feng Chao-Yue Zhang Hao liu Chuan Shi Xiao-Xian zhao jian-jun song College of Physics School of Chemistry and Chemical EngineeringQingdao UniversityQingdao266071China Faculty of Science Centre for Clean Energy TechnologySchool of Mathematical and Physical SciencesUniversity of Technology SydneySydneyNSW2007Australia Department of Chemistry College of ScienceHebei Agricultural UniversityBaoding071001China

The high-energy-density and low-cost features endow lithium-sulfur batteries with broad application ***,many drawbacks,especially the detrimental shuttle effect,have hindered the further development of *** response,a lot of new structures have been applied to suppress the shuttle effect and promote the development of ***,vacancy engineering has gained the attention of researchers due to its unique electronic *** review aims to analyze the application of vacancy engineering in ***,the electrochemistry of LSBs has been systematically discussed and the existing challenges as well as improvement tactics of LSBs have also been ***,the preparation methods and characterization technologies of various vacancies are summarized,including oxygen vacancies,sulfur vacancies,selenium vacancies,other anion vacancies,cation vacancies,*** latest applications of vacancy engineering in LSBs are also summarized in this ***,some prospects and insights for further investigation and practical application of vacancy engineering in LSBs are put forward.

关键词： Lithium-sulfur batteries(LSBs) Defects Vacancy engineering Electronic structure Shuttle effect