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Scintillation Arc from FRB 20220912A

Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 134-142页

作者： Zi-Wei Wu Robert AMain Wei-Wei Zhu Bing Zhang Peng jiang jia-rui niu Jin-Lin Han Di Li Ke-jia Lee Dong-Zi Li Yuan-Pei Yang Fa-Yin Wang rui Luo Pei Wang Chen-Hui niu Heng Xu Bo-Jun Wang Wei-Yang Wang Yong-Kun Zhang Yi Feng De-jiang Zhou Yong-Hua Xu Can-Min Deng Yu-Hao Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Max-Planck-Institut für Radioastronomie Bonn 53121Germany Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Nevada Center for Astrophysics and Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Department of Astronomy Peking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Cahill Center for Astronomy and Astrophysics California Institute of TechnologyPasadena 91125USA South-Western Institute For Astronomy Research Yunnan UniversityKunming 650504China School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210023China CSIRO Space and Astronomy Epping 1710Australia Department of Astronomy School of Physics and Materials ScienceGuangzhou UniversityGuangzhou 510006China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Yunnan Observatories Chinese Academy of SciencesKunming 650011China Guangxi Key Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

We present the interstellar scintillation analysis of fast radio burst(FRB)20220912A during its extremely active episode in 2022using data from the Five-hundred-meter Aperture Spherical Radio Telescope(FAST).We detect a scintillation arc in the FRB’s secondary spectrum,which describes the power in terms of the scattered FRB signals’time delay and Doppler shift.The arc indicates that the scintillation is caused by a highly localized region.Our analysis favors a Milky Way origin of the ionized interstellar medium(IISM)for the localized scattering medium but cannot rule out a host galaxy origin.We present our method for detecting the scintillation arc,which can be applied generally to sources with irregularly spaced bursts or pulses.These methods could help shed light on the complex interstellar environment surrounding the FRBs and in our Galaxy.

关键词： fast radio burst scintillation FRB 20220912A

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FAST Observations of an Extremely Active Episode of FRB 20201124A.Ⅱ.Energy Distribution

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Research in Astronomy and Astrophysics 2022年第12期22卷 70-80页

作者： Yong-Kun Zhang Pei Wang Yi Feng Bing Zhang Di Li Chao-Wei Tsai Chen-Hui niu rui Luo Ju-Mei Yao Wei-Wei Zhu Jin-Lin Han Ke-jia Lee De-jiang Zhou jia-rui niu Jin-Chen jiang Wei-Yang Wang Chun-Feng Zhang Heng Xu Bo-Jun Wang jiang-Wei Xu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA Nevada Center for Astrophysics University of NevadaLas VegasNV 89154USA NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa CSIRO Space and Astronomy PO Box 76EppingNSW 1710Australia Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy Peking UniversityBeijing 100871China

We report the properties of more than 800 bursts detected from the repeating fast radio burst(FRB)source FRB20201124A with the Five-hundred-meter Aperture Spherical radio Telescope(FAST)during an extremely active episode on UTC 2021 September 25–28 in a series of four papers.In this second paper of the series,we study the energy distribution of 881 bursts(defined as significant signals separated by dips down to the noise level)detected in the first four days of our 19 hr observational campaign spanning 17 days.The event rate initially increased exponentially but the source activity stopped within 24 hr after the 4th day.The detection of 542 bursts in one hour during the fourth day marked the highest event rate detected from one single FRB source so far.The bursts have complex structures in the time-frequency space.We find a double-peak distribution of the waiting time,which can be modeled with two log-normal functions peaking at 51.22 ms and 10.05 s,respectively.Compared with the emission from a previous active episode of the source detected with FAST,the second distribution peak time is smaller,suggesting that this peak is defined by the activity level of the source.We calculate the isotropic energy of the bursts using both a partial bandwidth and a full bandwidth and find that the energy distribution is not significantly changed.We find that an exponentially connected broken-power law function can fit the cumulative burst energy distribution well,with the lower and higher-energy indices being-1.22±0.01 and-4.27±0.23,respectively.Assuming a radio radiative efficiency ofη_(r)=10^(-4),the total isotropic energy of the bursts released during the four days when the source was active is already 3.9×10^(46)erg,exceeding~23%of the available magnetar dipolar magnetic energy.This challenges the magnetar models which invoke an inefficient radio emission(e.g.,synchrotron maser models).

关键词： (stars:)pulsars:general stars:individual(FRB 20201124A) methods:data analysis

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FAST Observations of an Extremely Active Episode of FRB 20201124A.Ⅳ.Spin Period Search

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Research in Astronomy and Astrophysics 2022年第12期22卷 99-122页

作者： jia-rui niu Wei-Wei Zhu Bing Zhang Mao Yuan De-jiang Zhou Yong-Kun Zhang Jin-Chen jiang J.L.Han Di Li Ke-jia Lee Pei Wang Yi Feng Dong-Zi Li rui Luo Fa-Yin Wang Zi-Gao Dai Chen-Chen Miao Chen-Hui niu Heng Xu Chun-Feng Zhang Wei-Yang Wang Bo-Jun Wang jiang-Wei Xu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA Department of Astronomy Peking UniversityBeijing 100871China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Cahill Center for Astronomy and Astrophysics MC 249-17 California Institute of TechnologyPasadena CA 91125USA CSIRO Space and Astronomy PO Box 76EppingNSW 1710Australia School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityMinistry of EducationNanjing 210093China Department of Astronomy University of Science and Technology of ChinaHefei 230026China

关键词： pulsars:general methods:observational radio continuum:general

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FAST Observations of an Extremely Active Episode of FRB 20201124A.Ⅲ.Polarimetry

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Research in Astronomy and Astrophysics 2022年第12期22卷 81-98页

作者： Jin-Chen jiang Wei-Yang Wang Heng Xu jiang-Wei Xu Chun-Feng Zhang Bo-Jun Wang De-jiang Zhou Yong-Kun Zhang jia-rui niu Ke-jia Lee Bing Zhang Jin-Lin Han Di Li Wei-Wei Zhu Zi-Gao Dai Yi Feng Wei-Cong Jing Dong-Zi Li rui Luo Chen-Chen Miao Chen-Hui niu Chao-Wei Tsai Fa-Yin Wang Pei Wang Ren-Xin Xu Yuan-Pei Yang Zong-Lin Yang Ju-Mei Yao Mao Yuan Department of Astronomy Peking UniversityBeijing 100871China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Department of Astronomy University of Science and Technology of ChinaHefei 230026China Cahill Center for Astronomy and Astrophysics MC 249-17California Institute of TechnologyPasadenaCA 91125USA CSIRO Space and Astronomy P.O.Box 76EppingNSW 1710Australia School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationChina South-Western Institute For Astronomy Research Yunnan UniversityYunnan 650504China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China

As the third paper in the multiple-part series,we report the statistical properties of radio bursts detected from the repeating fast radio burst(FRB)source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope during an extremely active episode between the 25th and 28th of September 2021(UT).We focus on the polarization properties of536 bright bursts with S/N>50.We found that the Faraday rotation measures(RMs)monotonically dropped from-579to-605 rad m^(-2)in the 4 day window.The RM values were compatible with the values(-300 to-900 rad m^(-2))reported 4 months ago.However,the RM evolution rate in the current observation window was at least an order of magnitude smaller than the one(~500 rad m^(-2)day^(-1))previously reported during the rapid RM-variation phase,but is still higher than the one(≤1 rad m^(-2)day^(-1))during the later RM no-evolution phase.The bursts of FRB 20201124A were highly polarized with the total degree of polarization(circular plus linear)greater than 90%for more than 90%of all bursts.The distribution of linear polarization position angles(PAs),degree of linear polarization(L/I)and degree of circular polarization(V/I)can be characterized with unimodal distribution functions.During the observation window,the distributions became wider with time,i.e.,with larger scatter,but the centroids of the distribution functions remained nearly constant.For individual bursts,significant PA variations(confidence level 5σ)were observed in 33%of all bursts.The polarization of single pulses seems to follow certain complex trajectories on the Poincarésphere,which may shed light on the radiation mechanism at the source or the plasma properties along the path of FRB propagation.

关键词： (stars:)pulsars:general stars:magnetars radio continuum:general polarization

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The Multi-parameter Test of Gravitational Wave Dispersion with Principal Component Analysis

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Research in Astronomy and Astrophysics 2024年第5期24卷 140-150页

作者： Zhi-Chu Ma rui niu Wen Zhao CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

In this work, we consider a conventional test of gravitational wave(GW) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity(GR)along the propagation of GWs. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis(PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multiparameter test with PCA. Whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.

关键词： gravitational waves-gravitation-black hole physics

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Living Chinese Herbal Scaffolds from Microfluidic Bioprinting for Wound Healing

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Research 2024年第1期2023卷 107-118页

作者： Xiaocheng Wang Jinxuan jia Mengying niu Wenzhao Li Yuanjin Zhao Department of Rheumatology and Immunology Nanjing Drum Tower HospitalSchool of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China Oujiang Laboratory(Zhejiang Lab for Regenerative Medicine Vision and Brain Health)Wenzhou InstituteUniversity of Chinese Academy of SciencesWenzhouZhejiang 325001China State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China Chemistry and Biomedicine Innovation Center Nanjing UniversityNanjing 210023China

Biological scaffolds have been widely employed in wound healing applications,while their practical efficiency is compromised by insufficient oxygen delivery to the 3-dimensional constructs and inadequate nutrient supply for the long-term healing process.Here,we present an innovative living Chinese herbal scaffold to provide a sustainable oxygen and nutrient supply for promoting wound healing.Through a facile microfluidic bioprinting strategy,a traditional Chinese herbal medicine(Panax notoginseng saponins[PNS])and a living autotrophic microorganism(microalgae Chlorella pyrenoidosa[MA])were successfully encapsulated into the scaffolds.The encapsulated PNS could be gradually released from the scaffolds,which promoted cell adhesion,proliferation,migration,and tube formation in vitro.In addition,benefiting from the photosynthetic oxygenation of the alive MA,the obtained scaffolds would produce sustainable oxygen under light illumination,exerting a protective effect against hypoxia-induced cell death.Based on these features,we have demonstrated through in vivo experiments that these living Chinese herbal scaffolds could efficiently alleviate local hypoxia,enhance angiogenesis,and thereby accelerate wound closure in diabetic mice,indicating their great potential in wound healing and other tissue repair applications.

关键词： healing wound protective

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Effect of La on the Corrosion Behavior and Mechanism of 3Ni Weathering Steel in a Simulated Marine Atmospheric Environment

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 308-324页

作者： Gang niu rui Yuan R.D.K.Misra Na Gong Zhi-Hui Zhang Hao-Xiu Chen Hui-Bin Wu Cheng-jia Shang Xin-Ping Mao Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing100083China Laboratory for Excellence in Advanced Steel Research Department of MetallurgicalMaterials and Biomedical EngineeringUniversity of Texas at El PasoEl PasoTX79968USA Institute of Materials Research and Engineering Agency for ScienceTechnologyand ResearchSingapore138634Singapore Department of Materials Science and Engineering University of TorontoTorontoONM5S 3E4Canada

The corrosion behavior and mechanism of 3Ni weathering steel in a simulated oceanic atmospheric environment are investigated in order to comprehend the impacts of La,as determined through electrochemical analysis and rust layer characterization.The results of this study demonstrate that the addition of La enhances the corrosion resistance of 3Ni weathering steel in the marine atmospheric environment,thereby reducing the corrosion rate and improving the protection of the rust layer.The influence of La on corrosion resistance can be attributed to two primary factors.Firstly,La functions as a grain refiner,minimizing the potential difference of the micro-regions on the substrate surface,thereby significantly reducing the corrosion of bare steel in the marine environment.Secondly,La inhibits the process of Fe_(3)O_(4) oxidation back toγ-FeOOH during corrosion at the local site,thus decreasing the formation ofγ-FeOOH and enhancing the charge transfer resistance.This research work may serve as a reference for expanding the application of rare earth elements in the field of weathering steel.

关键词： Weathering steel Rare earth Rust layer Corrosion behavior Corrosion resistance

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Charge-asymmetry Fe_(1)Cu single-atom alloy catalyst for efficient oxygen reduction reaction

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Nano Research 2024年第6期17卷 4702-4710页

作者： Xudong niu jian Wei Dongyao Xu jiajing Pei rui Sui School of Chemical&Environmental Engineering China University of Mining and TechnologyBeijing 100083China Institute of Water Ecology and Environment Chinese Research Academy of Environmental SciencesBeijing 100083China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China

The development of high-efficient and low-cost oxygen reduction reaction(ORR)electrocatalysts is crucial for the practical applications of metal-air batteries.One promising way is to develop Fe single-atom catalysts.However,the single active center and inherent electronic structure of Fe single-atom catalysts lead to the undesirable adsorption of multiple ORR intermediates.Herein,a charge-asymmetry single-atom alloy(SAA)catalyst with Fe-Cu dual sites supported on nitrogen-doped carbon nanosheet(Fe_(1)Cu SAA/NC)was constructed.Various characterizations manifest the existence of electron interaction between Fe and Cu in Fe_(1)Cu SAA/NC,which facilitates the adsorption of ORR intermediate for fast kinetics.Consequently,the charge-asymmetry Fe_(1)Cu SAA/NC exhibits much faster ORR kinetics with a half-wave potential of 0.917 V vs.reversible hydrogen electrode(RHE),outperforming its counterparts in the references.Furthermore,Fe_(1)Cu SAA/NC still maintains a high half-wave potential with only a drop of 5 mV after 5000 cycles,indicating excellent stability.This work provides a new strategy to design highly active and non-noble metal ORR electrocatalysts,which hold great potential for various catalytic applications.

关键词： Fe_(1)Cu single-atom alloy(SAA) electrocatalysis oxygen reduction reaction charge-asymmetry

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Carbon steel anticorrosion performance and mechanism of sodium lignosulfonate

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Rare Metals 2024年第1期43卷 356-365页

作者： Bo-Kai Liao rui-Xuan Quan Ping-Xian Feng Huan Wang Wei Wang Li niu School of Chemistry and Chemical Engineering Guangzhou Key Laboratory of Sensing Materials and DevicesJoint Institute of Guangzhou University and Institute of Corrosion Science and TechnologyGuangzhou UniversityGuangzhou 510006China

Lignin is a typical biological macromolecule with a three-dimensional network structure and abundant functional groups. It has excellent ionic complexation ability and amphiphilic molecular structure characteristics.In this study, the carbon steel anticorrosion performance of sodium lignosulfonate(SLS) in an acid solution was evaluated using the weight loss method, electrochemical measurements, scanning vibration electrode technique(SVET), and surface characterization methods. SLS exhibited excellent corrosion inhibition efficiency for Q235carbon steel in 1 mol·L^(-1) HCl, reaching a maximum value of 98%. A low SLS concentration of 20 mg·L^(-1) resulted in the maximum corrosion inhibition efficiency, which remained nearly constant at higher SLS concentrations.The SVET test demonstrated that the formation of an SLS adsorption film can impede corrosion. This study confirms the significance of the application of green biomass resources in the field of metal corrosion protection and green functional materials.

关键词： Lignin Sodium lignosulfonate Corrosion inhibitor Carbon Steel

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Identification of novel genes associated with atherosclerosis in Bama miniature pig

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Animal Models and Experimental Medicine 2024年第3期7卷 377-387页

作者： Dengfeng Ding Yuqiong Zhao Yunxiao jia Miaomiao niu Xuezhuang Li Xinou Zheng Hua Chen Laboratory Animal Center Chinese PLA General HospitalBeijingChina

Background:Atherosclerosis is a chronic cardiovascular disease of great concern.However,it is difficult to establish a direct connection between conventional small animal models and clinical practice.The pig's genome,physiology,and anatomy reflect human biology better than other laboratory animals,which is crucial for studying the pathogenesis of atherosclerosis.Methods:We used whole-genome sequencing data from nine Bama minipigs to perform a genome-wide linkage analysis,and further used bioinformatic tools to filter and identify underlying candidate genes.Candidate gene function prediction was performed using the online prediction tool STRING 12.0.Immunohistochemistry and immunofluorescence were used to detect the expression of proteins encoded by candidate genes.Results:We mapped differential single nucleotide polymorphisms(SNPs)to genes and obtained a total of 102 differential genes,then we used GO and KEGG pathway enrichment analysis to identify four candidate genes,including SLA-1,SLA-2,SLA-3,and TAP2.nsSNPs cause changes in the primary and tertiary structures of SLA-I and TAP2 proteins,the primary structures of these two proteins have undergone amino acid changes,and the tertiary structures also show slight changes.In addition,immunohistochemistry and immunofluorescence results showed that the expression changes of TAP2 protein in coronary arteries showed a trend of increasing from the middle layer to the inner layer.Conclusions:We have identified SLA-I and TAP2 as potential susceptibility genes of atherosclerosis,highlighting the importance of antigen processing and immune response in atherogenesis.

关键词： atherosclerosis candidate genes genome-wide linkage analysis major histocompatibility complex whole genome sequencing

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