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Commissioning of laser electron gamma beamline SLEGS at SSRF

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Nuclear Science and Techniques 2022年第7期33卷 103-114页

作者： Hong-Wei Wang Gong-Tao Fan long-xiang liu Hang-Hua Xu Wen-Qing Shen Yu-Gang Ma Hiroaki Utsunomiya long-long Song Xi-Guang Cao Zi-Rui Hao Kai-Jie Chen Sheng Jin Yu-Xuan Yang Xin-Rong Hu Xin-xiang Li Pan Kuang Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai201800China University of Chinese Academy of Science Beijing100049China Fudan University Shanghai200433China Department of Physics Konan UniversityKobe658-8501Japan ShanghaiTech University Shanghai201210China Zhengzhou University Zhengzhou450001China

The Shanghai Laser Electron Gamma Source(SLEGS)is a powerful gamma source that provides MeV gamma-ray beams for nuclear science and *** was developed as one of the 16 beamline stations in the Phase Ⅱ Project of the Shanghai Synchrotron Radiation *** slant-scattering mode is for the first time systematically employed in laser Compton scattering at SLEGS to produce energy-tunable quasi-monoenergetic gamma-ray *** SLEGS officially completed its commissioning from July to December *** rays in the energy range of 0.25-21.7 MeV with a flux of 2.1×10^(4)-1.2×10^(7) photons/s and an energy spread of 2-15% were produced during the *** paper reports the results from commissioning the SLEGS beamline.

关键词： SLEGS Laser Compton scattering Slant-scattering mode Backscattering mode

A Novel Design of a Pre-separation Panel Structure to Protect Against the Impact of an Explosion in an Aircraft Plenum Chamber

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Acta Mechanica Solida Sinica 2024年第1期37卷 166-180页

作者： Zongxing liu xiang Yang Jun liu School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China COMAC Shanghai Aircraft Design and Research Institute Shanghai 201210China

To reduce the damage of the pressurizing panel structure of a fuselage caused by an explosion at the“least risk bomb location”in an aircraft structure,a new pre-separation panel structure was designed to resist blast ***,the dynamic strain response and morphology of impact damage of the new pre-separation panel were measured in an impact damage ***,the commercial software LS-DYNA was used to calculate the propagation of the blast shock wave,and the results were compared with empirical equations to verify the rationality of the numerical calculation ***,the fluid–structure coupling method was used to calculate the damage process of the pre-separation panel structure under the impact of an explosion wave and an impact *** calculated results were in good agreement with the test results,which showed the rationality of the calculation method and the *** residual strength of the damaged pre-separation panel was significantly higher than that of the original damaged *** results show that the new pre-separation panel structure is reasonable and has certain significance for guiding the design of plenum chambers with strong resistance to implosion for aircraft fuselages.

关键词： Pre-separation panel structure Explosive response Residual strength Aircraft plenum chamber Least risk bomb location

PARP1-DNA co-condensation:the driver of broken DNA repair

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Signal Transduction and Targeted Therapy 2024年第6期9卷 2351-2353页

作者： xiang Wei Fangfang Zhou long Zhang Life Sciences Institute The Second Affiliated Hospital of the Zhejiang University School of MedicineThe MOE Key Laboratory of Biosystems Homeostasis&Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell BiologyZhejiang UniversityHangzhouChina The First Affiliated Hospital the Institutes of Biology and Medical SciencesSuzhou Medical CollegeSoochow UniversitySuzhouJiangsu 215123China

A recent study published by Simon Alberti1 in Cell has revealed that DNA double-strand break(DSB)sites that prevent the disjunction of broken DNA ends are formed through poly(ADPribose)(PAR)polymerase 1(PARP1)-DNA co-condensation.1(Fig.1).Here,a comprehensive and novel model was provided for the ordered assembly of PARP1-DNA condensates,which can rationally make clear broken DNA end synapses and how repair effectors are recruited to repair DSB.

关键词： PARP1 repair rational

Research on Pulsar Time Steered Atomic Time Algorithm Based on DPLL

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Research in Astronomy and Astrophysics 2024年第3期24卷 237-248页

作者： Ze-Hao Zheng Yang liu Dan Shen Fan Feng Jiu-long liu Yue-Xin Ma xiang-Wei Zhu School of Electronic and Communication Engineering Sun Yat-sen UniversityShenzhen 518107China School of Aeronautics and Astronautics Sun Yat-sen UniversityShenzhen 518107China School of Systems Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China

In today’s society,there is a wide demand for high-precision and high-stability time service in the fields of electric power,communication,transportation and *** present,the time standard in various countries is mainly based on atomic clocks,but the frequency drift of atomic clocks will affect the long-term stability *** with atomic clocks,millisecond pulsars have better long-term stability and can complement with the excellent short-term stability of atomic *** order to improve the long-term stability of the atomic timescale,and then improve the timing accuracy,this paper proposes an algorithm for steering the atomic clock ensemble(ACE)by ensemble pulsar time(EPT)based on digital phase locked loop(DPLL).First,the ACE and EPT are generated by the ALGOS algorithm,then the ACE is steered by EPT based on DPLL to calibrate the long-term frequency drift of the atomic clock,so that the generated steered atomic time follows both the short-term stability characteristics of ACE and the long-term stability characteristics of EPT,and finally,the steered atomic time is used to calibrate the local cesium *** experimental results show that the long-term stability of atomic time after steering is improved by 2 orders of magnitude compared with that before steering,and the daily drift of a local cesium clock after calibration is less than 9.47 ns in 3 yr,3 orders of magnitude higher than that before calibration on accuracy.

关键词： (stars) pulsars general-time-methods data analysis-instabilities

Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System

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China Ocean Engineering 2024年第1期38卷 29-41页

作者： LI Yan-wei liu Xiu-quan WANG Jin-long CHEN Guo-ming CHANG Yuan-jiang SHENG Lei-xiang Centre for Offshore Engineering and Safety Technology China University of PetroleumQingdao 266580China National Engineering Laboratory of Offshore Geophysical and Exploration Equipment China University of PetroleumQingdao 266580China China CNOOC Research Institute Co. Ltd.Beijing 100028China

The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of *** approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex *** accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβ*** analysis program is also developed in MATLAB for dynamic *** simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation *** bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and *** platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.

关键词： deepwater drilling riser new hang-off system dynamic analysis finite element method penalty function method

Review of dynamics and active control of large-scale space membrane antenna

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Astrodynamics 2024年第1期8卷 1-26页

作者： xiang liu Guoping Cai Department of Engineering Mechanics MOE Key Laboratory of HydrodynamicsChongqing Research InstituteShanghai Jiao Tong UniversityShanghai200240China

Large-scale space membrane antennas have significant potential in satellite communication,space-based early warning,and Earth *** of their large size and high flexibility,the dynamic analysis and control of membrane antenna are *** maintain the working performance of the antenna,the pointing and surface accuracies must be strictly ***,the accurate dynamic modeling and effective active control of large-scale space membrane antennas have great theoretical significance and practical value,and have attracted considerable interest in recent *** paper reviews the dynamics and active control of large-scale space membrane ***,the development and status of large-scale space membrane antennas are ***,the key problems in the dynamics and active control of large membrane antennas,including the dynamics of wrinkled membranes,large-amplitude nonlinear vibration,nonlinear model reduction,rigid-flexible-thermal coupling dynamic modeling,on-orbit modal parameter identification,active vibration control,and wave-based vibration control,are discussed in ***,the research outlook and future trends are presented.

关键词： large-scale space membrane antenna dynamicmodeling active control

Simulation and test of the SLEGS TOF spectrometer at SSRF

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Nuclear Science and Techniques 2023年第3期34卷 171-184页

作者： Kai-Jie Chen long-xiang liu Zi-Rui Hao Yu-Gang Ma Hong-Wei Wang Gong-Tao Fan Xi-Guang Cao Hang-Hua Xu Yi-Fei Niu Xin-xiang Li Xin-Rong Hu Yu-Xuan Yang Sheng Jin Pan Kuang School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China University of Chinese Academy of Science Beijing 100080China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China School of Nuclear Science and Technology University of South ChinaHengyang 421001China School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450052China

The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear *** goal of the SLEGS neutron time-of-flight(TOF)spectrometer is to measure GDR and specific nuclear structures in the energy region above the neutron *** SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 ***4 was used to simulate the efficiency of each detector and the entire spectrometer,which provides a reference for the selection of detectors and layout of the SLEGS TOF *** the events of 208Pb,implementations of coincidence and time-of-flight technology for complex experiments are available;thus,and neutron decay events can be *** performance of SLEGS TOF spectrometer was systematically evaluated using offline experiments,in which the time resolution reached approximately 0.9 ns.

关键词： SLEGS Time-of-flight Photoneutron nuclear reaction

Removal of Cr(Ⅵ)by glutaraldehyde-crosslinked chitosan encapsulating microscale zero-valent iron:Synthesis,mechanism,and longevity

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Journal of Environmental Sciences 2024年第8期142卷 115-128页

作者： Yijun Duan Fang liu xiang liu Miao Li School of Environment Tsinghua UniversityBeijing 100084China Transportation Institute of Inner Mongolia University Hohhot 010070China

Microscale zero-valent iron(mZVI)has shown great potential for groundwater Cr(Ⅵ)***,low Cr(Ⅵ)removal capacity caused by passivation restricted the wide use of *** prepared mZVI/GCS by encapsulating mZVI in a porous glutaraldehydecrosslinked chitosan matrix,and the formation of the passivation layer was alleviated by reducing the contact between zero-valent iron *** average pore diameter of mZVI/GCS was 8.775 nm,which confirmed the mesoporous characteristic of this *** of batch experiments demonstrated that mZVI/GCS exhibited high Cr(Ⅵ)removal efficiency in a wide range of pH(2-10)and temperature(5-35℃).Common groundwater coexisting ions slightly affected m ZVI/*** material showed great reusability,and the average Cr(Ⅵ)removal efficiency was 90.41%during eight *** this study,we also conducted kinetics and isotherms ***-second-order model was the most matched kinetics *** Cr(Ⅵ)adsorption process was fitted by both Langmuir and Freundlich isotherms models,and the maximum Langmuir adsorption capacity of m ZVI/GCS reached243.63 mg/g,which is higher than the adsorption capacities of materials reported in most of the previous ***,the column capacity for Cr(Ⅵ)removal of a mZVI/GCS-packed column was 6.4 times higher than that of a mZVI-packed column in a 50-day ***,mZVI/GCS with a porous structure effectively relieved passivation problems of mZVI and showed practical application prospects as groundwater Cr(Ⅵ)remediation material with practical application prospects.

关键词： Chitosan Glutaraldehyde mZVI Cr(Ⅵ) Groundwater

Localization−delocalization transitions in non-Hermitian Aharonov−Bohm cages

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Frontiers of physics 2024年第3期19卷 39-50页

作者： xiang Li Jin liu Tao liu School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

A unique feature of non-Hermitian systems is the extreme sensitivity of the eigenspectrum to boundary conditions with the emergence of the non-Hermitian skin effect (NHSE). A NHSE originates from the point-gap topology of complex eigenspectrum, where an extensive number of eigenstates are anomalously localized at the boundary driven by nonreciprocal dissipation. Two different approaches to create localization are disorder and flat-band spectrum, and their interplay can lead to the anomalous inverse Anderson localization, where the Bernoulli anti-symmetric disorder induces mobility in a full-flat band system in the presence of Aharonov−Bohm (AB) Cage. In this work, we study the localization−delocalization transitions due to the interplay of the point-gap topology, flat band and correlated disorder in the one-dimensional rhombic lattice, where both its Hermitian and non-Hermitian structures show AB cage in the presence of magnetic flux. Although it remains the coexistence of localization and delocalization for the Hermitian rhombic lattice in the presence of the random anti-symmetric disorder, it surprisingly becomes complete delocalization, accompanied by the emergence of NHSE. To further study the effects from the Bernoulli anti-symmetric disorder, we found the similar NHSE due to the interplay of the point-gap topology, correlated disorder and flat bands. Our anomalous localization−delocalization property can be experimentally tested in the classical physical platform, such as electrical circuit.

关键词： non-Hermitian skin effects disorder flat band localization−delocalization transition