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The SLEGS beamline of SSRF

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Nuclear Science and Techniques 2024年第7期35卷 20-30页

作者： Long-Xiang Liu Hong-wei Wang Gong-Tao fan hang-Hua Xu Yue Zhang Zi-Rui Hao Ai-Guo Li Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China

The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ rays of 0.25-21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10~7 photons/s at the target at 21.7 MeV, with a 3-mm-diameter beam. The beamline was equipped with four types of spectrometers for experiments in( γ,γ'),( γ,n),( γ,p), and( γ,α). At present, Nuclear Resonance Fluorescence(NRF) spectrometry, Flat-Efficiency neutron Detector(FED) spectrometry, neutron Time-Of-Flight(TOF) spectrometry, and Light-Charged Particle(LCP) spectrometry methods have been developed.

关键词： Shanghai Synchrotron Radiation Facility SLEGS Nuclear astrophysics Nuclear structure

OnFractional(g,f,n′,m)-Critical Covered Graphs

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Journal of the Operations Research Society of China 2024年第2期12卷 446-460页

作者： wei Gao wei-fan Wang School of Information Science and Technology Yunnan Normal UniversityKunming 650500YunnanChina Department of Mathematics Zhejiang Normal UniversityJinhua 321004ZhejiangChina

The main contribution in this article is threefold:(1)we show the necessary and sufficient condition for graphs to be fractional(g,f)-covered which can be expressed in different forms,and extended to fractional(g,f,m)-covered graphs;(2)the concept of fractional-critical covered graph is put forward and its necessary and sufficient condition is given;(3)we present the degree condition for a graph to be fractional(g,f,n′,m)-critical covered,and show that degree bound is sharp when m is ***,the related result in fractional(a,b,n′,m)-critical covered setting is also verified.

关键词： Network Fractional factor Data transmission Fractional covered graph Fractional critical covered graph

Numerical simulation of formaldehyde distribution characteristics in the high-speed train cabin

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Building Simulation 2024年第2期17卷 285-300页

作者： fan Wu hang Dong Chao Yu Hengkui Li Qingmin Cui Renze Xu Key Laboratory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangshaHunan410075China Joint International Research Laboratory of Key Technologies for Rail Traffic Safety ChangshaHunan410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle ChangshaHunan410075China School of Software Henan University of EngineeringZhengzhouHenan451191China

The global concern over indoor air pollution in public vehicles has grown *** a focus on enhancing passengers’comfort and health,this study endeavors to investigate the distribution characteristics of formaldehyde within a high-speed train cabin by employing a computational fluid dynamics(CFD)model which is experimentally validated in a real cabin *** research focuses on analyzing the impact of air supply modes,temperature,relative humidity,and fresh air change rate on the distribution and concentration of *** results demonstrate that the difference in average formaldehyde concentration between the two air supply modes is below 1.3%,but the top air supply mode leads to a higher accumulation of formaldehyde near the sidewalls,while the bottom air supply mode promotes a more uniform distribution of ***,the temperature,relative humidity,and fresh air change rate are the primary factors affecting formaldehyde concentration levels,but they have modest effects on formaldehyde’s distribution pattern within the *** the temperature and relative humidity increase,the changes in formaldehyde concentrations in response to variations in these factors become more ***,the formaldehyde concentration may surpass the standard limit of 0.10 mg/m^(3)if the fresh air change rate falls below 212 m^(3)/*** research provides a systematic approach and referenceable results for exploring formaldehyde pollution in high-speed train cabins.

关键词： indoor air pollution formaldehyde CFD simulation high-speed train ventilation

Exploring precursor effect in in-situ reconstruction of Bi metal organic-frameworks during CO_(2)electroreduction reaction to tailor formate selectivity towards 100%

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Science China Chemistry 2024年第7期67卷 2190-2198页

作者： Zhida Liu Qikui fan hang Huo fanglei Yao Xiaoping Gao Jin Wang College of Materials Science and Engineering Shenzhen UniversityShenzhen 518071China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

Bi-based metal-organic frameworks(Bi-MOFs)as efficient catalysts for the CO_(2)electroreduction reaction(CRR)have been extensively *** has been established that Bi-MOFs usually undergo in-situ transformation during the CRR,ultimately converting into Bi ***,the effect of the MOF precursors on the structure of the derived Bi catalysts and consequently on their electrocatalytic properties has not been clearly *** this work,we prepared four variants of a novel Bi-MOF with different morphologies and dimensions,and explored the effects of the precursors on the resulting Bi catalysts and their CRR performance.A precursor-dependent in-situ transformation and its profound impact on tuning the CO_(2)-formate FE towards~100%have been *** the four examined variants,Bi-MOF with nanocube-like morphology(BiMOF-NC)is transformed into thin and flat Bi nanosheets capable of successfully enveloping the fibers of carbon paper(working electrode),while the other three variants with increased size and dodecahedral/octahedral geometry have been transformed into Bi nanoflowers,exposing a fair portion of the carbon fibers in the working ***,the transformation rate was found to be dependent on the precursors and BiMOF-NC exhibited the highest rate of reconstruction compared with other ***,the Bi catalyst derived from BiMOF-NC delivered a selectivity for the formate product of nearly 100%at-1.2 V(*** hydrogen electrode(RHE))and of over 95%in a wide potential range due to efficient suppression of the competing hydrogen evolution reaction(HER)over carbon *** in-situ transformed BiMOFNC also demonstrated equivalently high formate selectivity at large current densities(≥100 mA cm^(-2))in flow cell reactors as that in H-type reactors,underscoring its potential for industrial *** work highlights the necessity of finely tuning the structural features of MOF precursors to achieve optim

关键词： Bi-MOFs precursor effect in-situ transformation Bi nanosheets CO_(2)-to-formate

Nearly degenerate ground states of a checkerboard antiferromagnet and their bosonic interpretation

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 84-89页

作者： Haiyuan Zou fan Yang wei Ku Key Laboratory of Polar Materials and Devices(MOE) School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China Department of Physics Beijing Institute of TechnologyBeijing 100081China Tsung-Dao Lee Institute Shanghai 200240China Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education) Shanghai 200240China Shanghai Branch Hefei National LaboratoryShanghai 201315China

The spin-1/2 model system with antiferromagnetic(AF) couplings on a J1-J2checkerboard lattice, known as the planar pyrochlore model, is strongly frustrated and associated with a two-to-one dimensional crossover. Using the Projected Entangled Simplex States tensor network ansatz, we identify a large number of nearly degenerate states in the frustrated region(J_(1)

关键词： tensor networks frustrated magnetism dimensional crossover degenerate states

Characteristics and source apportionment of ambient volatile organic compounds and ozone generation sensitivity in urban Jiaozuo,China

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Journal of Environmental Sciences 2024年第4期138卷 607-625页

作者： Pengzhao Li Chun Chen Dan Liu Jie Lian wei Li Chuanyi fan Liangyu Yan Yue Gao Miao Wang hang Liu Xiaole Pan Jing Mao State Centre for International Cooperation on Designer Low-Carbon and Environmental Materials School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China Henan Key Laboratory of Environmental Monitoring Technology Henan Ecological Environment Monitoring and Safety CenterZhengzhou 450046China Jiaozuo Ecological Environment Monitoring Center of Henan Province Jiaozuo 454003China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

In recent years,many cities have taken measures to reduce volatile organic compounds(VOCs),an important precursor of ozone(O_(3)),to alleviate O_(3) pollution in China.116 VOC species were measured by online and offline methods in the urban area of Jiaozuo from May to October in 2021 to analyze the compositional *** sources were analyzed by a positive matrix factorization(PMF)model,and the sensitivity of ozone generation was determined by ozone isopleth plotting research(OZIPR)*** results showed that the average volume concentration of total VOCs was 30.54 ppbv and showed a bimodal feature due to the rush-hour traffic in the morning and at *** most dominant VOC groups were oxygenated VOCs(OVOCs,29.3%)and alkanes(26.7%),and the most abundant VOC species were acetone and ***,based on the maximum incremental reactivity(MIR)method,the major VOC groups in terms of ozone formation potential(OFP)contribution were OVOCs(68.09μg/m^(3),31.5%),aromatics(62.90μg/m^(3),29.1%)and alkene/alkynes(54.90μg/m^(3),25.4%).This indicates that the control of OVOCs,aromatics and alkene/alkynes should take *** sources of VOCs were quantified by PMF,including fixed sources of fossil fuel combustion(27.8%),industrial processes(25.9%),vehicle exhaust(19.7%),natural and secondary formation(13.9%)and solvent usage(12.7%).The empirical kinetic modeling approach(EKMA)curve obtained by OZIPR on O_(3) exceedance days indicated that the O_(3) sensitivity varied in different *** results provide theoretical support for O_(3) pollution prevention and control in Jiaozuo.

关键词： Volatile organic compounds(VOCs) Online and offline measurement Ozone formation potential(OFP) Positive matrix factorization(PMF) Ozone isopleth plotting research(OZIPR) Jiaozuo

Anomalies of Precipitation over China on Days with Tropical Cyclone Activity over the Bay of Bengal: Role of Moisture Transport

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Journal of Meteorological Research 2024年第2期38卷 368-382页

作者： Na wei Ying LI Xiaoting fan Nanjing Joint Institute for Atmospheric Sciences Nanjing 210041 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433

Tropical cyclones over the Bay of Bengal(BoBTC)affect the precipitation over China,with distinct seasonal and daily *** study quantitatively examines the daily standardized precipitation anomalies(SPAs)over China on the days with BoBTC activities(storm-days)and related circulations,based on rainfall measurements at surface meteorological stations and ECMWF reanalysis data on a 0.25°×0.25°resolution during *** positive SPA is found over the stations in the two adjacent regions around BoB(Southwest China in May/November and southern Tibetan Plateau in October)and three distant regions(Southeast China and the northeastern boundary of the Qinghai-Tibet Plateau in May,and central North China in October).The SPA distributions are remarkably consistent with the integrated water vapor transport(IVT)*** IVT is found associated with the interaction between southwesterly(southerly)of the BoBTC circulation and low-level monsoonal flow in May(midlevel westerly in winter months).The probabilities of extreme precipitation(EP)occurrences over the above regions all increase on *** adjacent regions,EP is significantly correlated with the northward IVT anomalies to the east of BoBTC circulation,which strengthen the water vapor input through the southern *** IVT anomalies are stronger in May,benefited by the deep monsoonal southwesterlies than those in *** distant regions,EP is more closely related to the IVT anomaly extending back from *** moisture from BoB concentrates along a local low-level convergence line over Southeast China,being further facilitated by coexistence of the BoBTC depression and midlevel westerly trough in *** results highlight the interactions between BoBTCs and local weather systems that influence the general precipitation anomalies and occurrence of EP over China,especially over distant regions.

关键词： tropical cyclone Bay of Bengal precipitation anomaly moisture transport

New insight into Ca^(2+)-permeable channel in plant immunity

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Journal of Integrative Plant Biology 2024年第3期66卷 623-631页

作者： wei Wang hang-Yuan Cheng Jian-Min Zhou State Key Laboratory of Plant Genomics Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Biotic Interactions University of Chinese Academy of SciencesBeijing 100049China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100049China Hainan Yazhou Bay Seed Laboratory Sanya 572025China

Calcium ions(Ca^(2+)) are crucial intracellular second messengers in eukaryotic cells. Upon pathogen perception, plants generate a transient and rapid increase in cytoplasmic Ca^(2+)levels, which is subsequently decoded by Ca^(2+)sensors and effectors to activate downstream immune responses. The elevation of cytosolic Ca^(2+)is commonly attributed to Ca^(2+)influx mediated by plasma membranelocalized Ca^(2+)–permeable channels. However, the contribution of Ca^(2+)release triggered by intracellular Ca^(2+)-permeable channels in shaping Ca^(2+)signaling associated with plant immunity remains poorly understood. This review discusses recent advances in understanding the mechanism underlying the shaping of Ca^(2+)signatures upon the activation of immune receptors, with particular emphasis on the identification of intracellular immune receptors as non-canonical Ca^(2+)-permeable channels. We also discuss the involvement of Ca^(2+)release from the endoplasmic reticulum in generating Ca^(2+)signaling during plant immunity.

关键词： Ca^(2+)-permeable channels endoplasmic reticulum phosphorylation plant immunity resistosome

Density-Functional Theories for Polyelectrolyte Systems

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Chinese Journal of Polymer Science 2024年第9期42卷 1302-1312,I0006页

作者： Jia-wei Zhang Yu-hang Zhang Bao-Hui Li Qiang Wang School of Physics Nankai UniversityTianjin90001China Department of Chemical and Biological Engineering Colorado State University1370 Campus DeliveryFort CollinsCO80523-1370USA

Polymer density-functional theories(PDFTs)have distinct advantages in the study of polyelectrolyte(PE)systems over experiments and molecular *** we give an introductory review of some PDFTs recently developed for PE *** start with a general formalism of PDFTs and its relation to the widely used polymer self-consistent field theory(SCFT),then explain the various correlations that are neglected in SCFT but can be accounted for in PDFTs,including those due to the excluded-volume interaction and chain connectivity of uncharged polymers,the electrostatic correlations of small ions,and the chain correlations in *** also list some applications of PDFTs for PE systems,and finally give some perspectives on future *** hope that our review can attract more researchers to apply and further develop PDFTs as a promising class of theoretical and computational tools.

关键词： Polymer density-functional theories Polyelectrolytes Correlations