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Properties of collective flow and pion production in intermediate-energy heavy-ion collisions with a relativistic quantum molecular dynamics model

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Nuclear Science and Techniques 2024年第1期35卷 155-169页

作者： Si-na wei Zhao-Qing Feng School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(***). Using the ***, the properties of collective flow and pion production were investigated systematically for nuclear reactions with various isospin asymmetries. The directed and elliptic flows of the *** are able to describe the experimental data of STAR Collaboration. The directed flow difference between free neutrons and protons was associated with the stiffness of the symmetry energy, that is, a softer symmetry energy led to a larger flow difference. For various collision energies, the ratio between the π^(-) and π^(+) yields increased with a decrease in the slope parameter of the symmetry energy. When the collision energy was 270 MeV/nucleon, the single ratio of the pion transverse momentum spectra also increased with decreasing slope parameter of the symmetry energy in both nearly symmetric and neutron-rich ***, it is difficult to constrain the stiffness of the symmetry energy with the double ratio because of the lack of threshold energy correction on the pion production.

关键词： Heavy-ion collision Collective flow Pion production Symmetry energy Relativistic mean field

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

Dynamic Response Impact of Vehicle Braking on Simply Supported Beam Bridges with Corrugated Steel Webs Based on Vehicle-Bridge Coupled Vibration Analysis

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 3467-3493页

作者： Yan Wang Siwen Li na wei School of Civil Engineering Zhengzhou UniversityZhengzhou450001China

A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle *** modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this *** method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are *** results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the ***,the influence of wheelto-bridge friction forces is of particular significance and cannot be *** the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking *** favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by *** is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.

关键词： Corrugated steel web girder bridges simply supported beam bridges vehicle-bridge coupled vibration braking impact factor

Diffuse emission of TeV neutrinos and gamma-rays from young pulsars by photomeson interaction in the Galaxy

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Research in Astronomy and Astrophysics 2013年第9期13卷 1097-1106页

作者： Zhi-Xiong Li Gui-Fang Lin wei-wei na Department of Physics Yunnan University Yunnan Astronomical Observatory National Astronomical Observatories Chinese Academy of Sciences Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Department of Physics Yuxi Normal University

It is generally believed that young, rapidly rotating pulsars are important sites of particle acceleration, in which protons can be accelerated to relativistic energy above the polar cap region if the magnetic moment is antiparallel to the spin axis （μ·Ω 〈 0）. To obtain diffuse neutrinos and gamma-rays at TeV that originate in our Galaxy, we use the Monte Carlo method to generate a sample of young pulsars with ages less than 106 yr in our galaxy; the neutrinos and high-energy gamma-rays can be produced through a photomeson process with the interaction of energetic protons and soft X-ray photons （p ＋γ→△＋→n＋π＋/p＋π0） for a single pulsar, and these X-ray photons come from the surface of the neutron star. The results suggest that the flux of diffuse neutrinos at TeV energies is lower than the background flux, indicating they are difficult to detect using current neutrino telescopes.

关键词： pulsars: general -- stars: neutron -- neutrinos and gamma-rays: stars --elementary: neutrinos

Effect of Ambient Temperature on the Electrochemical Properties of La_4MgNi_(17.5)Co_(1.5) Hydrogen Storage Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第7期29卷 614-618页

作者： Xin Cai Fan-Song wei Fan-na wei Huan-Huan Lu Department of Material Science and Engineering Jiangsu University of Science and Technology

The effect of different ambient temperatures on the electrochemical properties of La4MgNi17.5C01.5 hydrogen storage alloy was investigated. The X-ray diffraction pattern shows that the alloy consists of LaNis-type phase and AsB19- type （Ce5C019 ＋ Pr5CO19） phase. With the increase of the ambient temperature, the maximum discharge capacity of the alloy electrodes increases from 353.33 （283 K） to 379.25 mAh/g （308 K）, and the cyclic stability （Sloo） of the electrodes decreases from 80.19 （283 K） to 52.04% （308 K） due to the acceleration of pulverization, corrosion and oxidation at higher ambient temperature. Moreover, it is found that the increase of the temperature can accelerate the diffusion rate of hydrogen in the alloy （D） and increase the exchange current density （Io）, which are beneficial for improving the activation performance and the high-rate dischargeability （HRD） of the alloy electrodes. The activation cycles of the electrodes decrease from 4 （283 K） to 1 （308 K）, and the HRD9oo of the electrodes sharply increases from 66.36 （283 K） to 95.64% （308 K）.

关键词： Hydrogen storage alloy Ambient temperature AsB19 type Electrochemical property

Strangeness to increase the density of finite nuclear systems in constraining the high-density nuclear equation of state

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Nuclear Science and Techniques 2017年第12期28卷 244-247页

作者： wei-Zhou Jiang Rong-Yong Yang Si-na wei Department of Physics Southeast UniversityNanjing 211189China

As the high-density nuclear equation of state(EOS) is not very well constrained, we suggest that the structural properties from the finite systems can be used to extract a more accurate constraint. By including the strangeness degrees of freedom, the hyperon or anti-kaon, the finite systems can then have a rather high-density core which is relevant to the nuclear EOS at high densities directly. It is found that the density dependence of the symmetry energy is sensitive to the properties of multi-K hypernuclei, while the high-density EOS of symmetric matter correlates sensitively to the properties of kaonic nuclei.

关键词： Nuclear equation of state Relativistic meanfield theory Strangeness

A signal-amplified whole-cell biosensor for sensitive detection of Hg^2+ based on Hg^2+-enhanced reporter module

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Journal of Environmental Sciences 2020年第10期32卷 93-98页

作者： Dan Wang Yanan Zheng Liudan wei na wei Xiaosu Fan Shan Huang Qi Xiao College of Chemistry and Materials Guangxi Key Laboratory of Natural Polymer Chemistry and PhysicsNanring Normal UniversityNanning 530001China Experimental Center of College of Agriculture Guangxi UniversityNanning 530005China

A signal-amplified mercury sensing biosensor with desired sensitivity was developed through firstly using the GFP mutant with fluorescence increasing response towards Hg^2+ as the reporter *** developed biosensor showed response for Hg^2+ in a relatively wide range of 1–10,000 nmol/L,and the detection limit was improved one or two orders of magnitude in comparison with most metal-sensing biosensors in similar *** addition,the biosensor could distinguish Hg^2+ easily from multiple metal ions and displayed strong adaptability to extensive p H conditions (pH 4.0–10.0).More importantly,the developed biosensor was able to provide an initial assessment of Hg^2+ spiked in the environmental water with the recoveries between 85.70%and 112.50%.The signal-amplified strategy performed by the modified reporter module will be widely applicable to many other wholecell biosensors,meeting the practical requirements with sufficient sensing performance.

关键词： Mercury sensing biosensor Signal-amplified Reporter module Environmental samples monitoring

The rate of period change in DAV stars

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Research in Astronomy and Astrophysics 2017年第7期17卷 11-24页

作者： Yan-Hui Chen Cai-Yun Ding wei-wei na Hong Shu Institute of Astrophysics Chuxiong Normal University School of Physics and Electronical Science Chuxiong Normal University Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences School of Physics and Electronic Engineering Yuxi Normal University

Grids of DAV star models are evolved by WDEC, taking the element diffusion effect into account. The grid parameters are hydrogen mass log（MH/M＊）, helium mass log（MHe/M＊）, stellar mass M＊and effective temperature T_（eff） for DAV stars. The core compositions are from white dwarf models evolved by MESA. Therefore, DAV star models evolved by WDEC have historically viable core compositions. Based on those DAV star models, we studied the rate of period change（P˙（k）） for different values of H, He, M_＊and Teff. The results are consistent with previous work. Two DAV stars G117-B15A and R548 have been observed for around 40 years. The rates of period change of two large-amplitude modes were obtained through the O-C method. We conducted an asteroseismological study on the two DAV stars and then obtained a best-fitting model for each star. Based on the two best-fitting models,the mode identifications（l, k） of the observed modes for G117-B15A and R548 are consistent with previous work. Both the observed modes and the observedP˙ s can be fitted by calculated ones. The results indicate that our method of evolving DAV star models is feasible.

关键词： stars oscillations (including pulsations) - stars individual (G117-B 15A and R548) -white dwarfs

Compound of icariin,astragalus,and puerarin mitigates iron overload in the cerebral cortex of Alzheimer＇s disease mice

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Neural Regeneration Research 2018年第4期13卷 731-736页

作者： Yu Zhang wei-na Kong Xi-Qing Chai Department of Neurology the First Hospital of Hebei Medical University Shijiazhuang Hebei Province China Hebei Chemical and Pharmaceutical College Shijiazhuang Hebei Province China

Increasing evidence indicates that disruption of normal iron homeostasis may contribute to pathological development of Alzheimer＇s ***,astragalus,and puerarin have been shown to suppress iron overload in the cerebral cortex and improve spatial learning and memory disorders in Alzheimer＇s disease mice,although the underlying mechanism remains *** the present study,APPswe/PS1ΔE9 transgenic mice were administered icariin,astragalus,and puerarin（120,80,and 80 mg/kg,respectively,once a day,for 3 months）.Iron levels were detected by flame atomic absorption ***-1β,interleukin-6,and tumor necrosis factor-α levels were measured in the cerebral cortex by enzyme linked immunosorbent *** peroxidase and superoxide dismutase activity and malondialdehyde content were determined by *** results demonstrate that after treatment,iron levels and malondialdehyde content are decreased,while glutathione peroxidase and superoxide dismutase activities are ***,interleukin-1β,interleukin-6,and tumor necrosis factor-α levels were *** results confirm that compounds of icariin,astragalus,and puerarin may alleviate iron overload by reducing oxidative stress and the inflammatory response.

关键词： nerve regeneration Alzheimer's disease iron overload icariin astragalus puerarin oxidative stress inflammatory response neural regeneration