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The contribution of the first forbidden transitions to the nuclear β^--decay half-life

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Chinese Physics C 2019年第11期43卷 91-99页

作者：游击林张小平支启军任中州吴庆东 School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China guizhou Provincial Key Laboratory of radio astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China School of Physics Science and Engineering Tongji UniversityShanghai 200092China

β-decay half-life is a key quantity for nuclear structure and nucleosynthesis *** exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits the resolution of the predictedβ-decay *** systematically study the contribution of the first forbidden(FF)transitions to theβ--decay half-life,and quantify it with a formula based on simple physics *** also propose a new formula for calculation of theβ--decay half-life that includes the FF *** is shown that the inclusion of the contribution of FF transitions significantly improves the precision of calculations of theβ--decay *** fitting of the RQRPA results for neutron-rich Z=47,57 isotopes and N=80,94 isotones,the formula for the contribution of the FF transitions gives similar results as the RQRPA ***,because of limited experimental data for the branching ratios of unstable nuclei,the fit parameters are not fully ***,the proposed formula for theβ--decay half-life is more suitable for calculations of half-lives than of the FF *** formula could be used to predict theβ?-decay half-life in nuclear structure studies as well as nucleosynthesis calculations in stars.

关键词： β^--decay half-life nucleosynthesis first forbidden transitions branching ratios

An RFI Mitigation Pipeline for CRAFTS Multi-beam Data Based on Signal Cross-Correlation Function and SumThreshold Algorithm

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Research in astronomy and Astrophysics 2023年第5期23卷 160-171页

作者： Zong-Hao Chen Shan-Ping You Xu-Hong Yu Pei Wang Di Li Xiao-Yao Xie Zhi-Jie Liu Chun-Qing Wang Peng Zeng Bin Zhang Key Laboratory of Information and Computing Science guizhou Province Guizhou Normal UniversityGuiyang 550001China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China Institute for Frontiers in astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa

The increasing radio frequency interference(RFI)is a well-recognized problem in radio astronomy *** and Fast radio Bursts(FRBs)are high-priority science targets of the ongoing Commercial radio astronomy FAST Survey(CRAFTS).To improve the quality of RFI removal in searches of pulsars and FRBs based on CRAFTS multi-beam data,we here propose an intuitive but powerful RFI mitigation pipeline(CCF-ST).The“CCF-ST”is a spatial filter constructed by signal cross-correlation function(CCF)and Sum-Threshold(ST)*** RFI marking result is saved in a“mask”file,a binary format for RFI masks in *** known pulsars,PSR B0525-21,PSR B0621-04,and PSR J0943+2252 from CRAFTS L-band 19 beams data are used for evaluation of the performance of CCF-ST in comparison with other methods,such as PRESTO’s“rfifind”,ArPLS-ST and *** result shows that CCF-ST can reduce effective data loss rate and improves the detected signal-to-noise ratio of the pulsations by~26%and~18%respectively compared with PRESTO’s“rfifind”and *** CCF-ST also has the advantage of low computational cost,e.g.,reducing the time consumption by~40%and memory consumption by~90%compared with *** expect that the new RFI mitigation and analysis toolkit(CCF-ST)demonstrated in this paper can be applied to CRAFTS and other multi-beam telescope observations to improve the data quality and efficiency of pulsar and FRB searches.

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

Studies on the Equatorial Spot of G-type Contact Binary UV Lyn

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Research in astronomy and Astrophysics 2022年第2期22卷 53-61页

作者： Jing-Jing Wang Bin Zhang Lin-Qiao Jiang China University of Petroleum–Beijing at Karamay Anding Road 355834000 KaramayChina School of Physics and Electronic Science Guizhou Normal University550025 GuiyangChina School of Physics and Electronic Engineering Sichuan University of Science Engineering643000 ZigongChina

New CCD photometric observations of G-type contact binary UV Lyn were obtained in 2006 and 2020,when the light curves(LCs)showed positive O'Connell effect and negative O'Connell effect,*** the previous studies,the LCs by other ground-based telescope are variable from 1973 to 2020,particularly the magnitude difference between the two *** phenomena indicate that the component has been active in the past 47 *** addition,during monitoring by the space telescope Transiting Exoplanet Survey Satellite(TESS)from January to March 2020,we fortunately found continuous variations from the O'Connell effect in every cycle for the first *** analysis also shows that in a short time,the positive O'Connell effect has been transformed into the negative one,which demonstrates that there are stronger magnetic activities on the surface of the *** using the Wilson-Devinney code with a spot model,these photometric solutions confirm UV Lyn is a shallow W-subtype contact binary with a cool equatorial spot on the less massive *** successive variability of the O'Connell effect possibly results from one equatorial cool spot shifting gradually along with *** also investigated its O-C curve from these continuous LCs,and there is no apparent variation in such a short ***,regarding the O'Connell effect as the indicator of magnetic activity indicates the system is possibly undergoing a periodic trend with a period of nearly 38 *** with the trend of the O-C curve,we could not find any relation between the period variation and magnetic activity.

关键词： (stars:)binaries(including multiple):close stars:solar-type stars:magnetic field

A GPU based single-pulse search pipeline(GSP)with database and its application to the Commensal radio astronomy FAST Survey(CRAFTS)

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Research in astronomy and Astrophysics 2021年第12期21卷 488-498页

作者：游善平王培于徐红谢晓尧李菂刘志杰潘之辰岳友岭钱磊张彬陈宗浩 School of Computer Science and Technology Guizhou UniversityGuiyang 550025China Key Laboratory of Information and Computing Science guizhou Province Guizhou Normal UniversityGuiyang 550001China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China NAOC-UKZN Computational Astrophysics Centre University of Kwa Zulu-NatalDurban 4000South Africa

We developed a GPU based single-pulse search pipeline(GSP)with a candidate-archiving *** based upon the infrastructure of the open source PulsaR Exploration and Search Toolkit(PRESTO),GSP implements GPU acceleration of the de-dispersion and integrates a candidate-archiving *** applied GSP to the data streams from the Commensal radio astronomy FAST Survey(CRAFTS),which resulted in quasi-real-time *** integrated candidate database facilitates synergistic usage of multiple machine-learning tools and thus improves efficient identification of radio pulsars such as rotating radio transients(RRATs)and fast radio bursts(FRBs).We first tested GSP on pilot CRAFTS observations with the FAST Ultra-Wide Band(UWB)*** detected all pulsars known from the the Parkes multibeam pulsar survey in the corresponding sky area covered by the *** also discovered 13 new *** measured the computational efficiency of GSP to be~120 times faster than the original PRESTO and~60 times faster than an MPI-parallelized version of PRESTO.

关键词： methods:data analysis pulsars:general surveys:astronomical databases

Atlas of dynamic spectra of fast radio burst FRB 20201124A

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Chinese Physics B 2023年第2期32卷 1-4页

作者：王铂钧胥恒姜金辰徐江伟牛佳瑞陈平李柯伽张冰朱炜玮东苏勃张春风傅海周德江张永坤王培冯毅李晔李冬子鲁文宾杨元培 RNCaballero 蔡策陈卯蒸戴子高艾力·伊沙木丁甘恒谦韩金林郝龙飞黄玉祥姜鹏李承奎李菂李辉李新乔李志玄刘志勇罗睿门云鹏牛晨辉彭文溪钱磊宋黎明孙京海王发印汪敏王娜王维扬吴雪峰肖硕熊少林徐永华徐仁新杨俊杨轩姚蕊易祁彬岳友岭于东俊余文飞袁建平张彬彬张松波张双南赵一郑伟康朱岩邹金航 Kavli Institute for astronomy and Astrophysics Peking UniversityBeijing 100871China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Department of astronomy Peking UniversityBeijing 100871China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Department of Particle Physics and Astrophysics Weizmann Institute of ScienceRehovot 76100Israel Nevada Center for Astrophysics University of NevadaLas VegasNV 89154USA Department of Physics and astronomy University of NevadaLas VegasNV 89154USA Department of Physics&astronomy University of IowaIowa CityIA 52242USA Zhejiang Laboratory HangzhouZhejiang 311121China Purple Mountain observatory Chinese Academy of SciencesNanjing 210008China TAPIR Walter Burke Institute for Theoretical PhysicsMail Code 350-17CaltechPasadenaCA 91125USA Department of astronomy University of California at BerkeleyBerkeleyCA 94720USA South-Western Institute For astronomy Research Yunnan UniversityYunnan 650504China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China University of Science and Technology of China Anhui 230026China Yunnan Observatories Chinese Academy of SciencesKunming 650216China guizhou Normal University Guiyang 550001China CSIRO Space and astronomy EppingNSW 1710Australia Max-Planck institut fur radioastronomie Auf Dem HugelBonn53121Germany School of astronomy and Space Science Nanjing UniversityNanjing 210093China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Shanghai Astronomical observatory Chinese Academy of SciencesShanghai 200030China Key Laboratory of Modern astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210093China College of Physics Hebei Normal UniversityShijiazhuang 050024China

Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://***/10.57760/sciencedb.j00113.00076.

关键词： fast radio burst FAST

The design of China Reconfigurable ANalog-digital backEnd for FAST

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Research in astronomy and Astrophysics 2020年第5期20卷 155-164页

作者： Xin-Xin Zhang Ran Duan Xin-Ying Yu Di Li Ning-Yu Tang Tao-Chung Ching National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China guizhou University Guiyang 550025China

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)was launched on 2016 September *** early 2017,we began to use the FAST wideband receiver,which was designed,constructed and installed on the FAST in guizhou,*** front end of the receiver is composed an uncooled Quad Ridge Flared Horn feed(QRFH)with the frequency range of 270 to 1620 MHz,and a cryostat operating at 10 *** have cooperated with the Institute of Automation of the Chinese Academy of Sciences to develop the China Reconfigurable ANalog-digital backEnd(CRANE).The system covers the 3 GHz operating band of *** hardware part of the backend includes an Analog Front-end Board,a wideband high precision Analog Digital Converter,and a FAST Digital *** circuit boards,field programmable gate arrays,and control computers form a set of hardware,software,and firmware platforms to achieve flexible bandwidth requirements through parameter *** is also suitable for the versatility of different astronomical observations,and can meet specific *** paper briefly introduces the hardware and software of CRANE,as well as some observations of the system.

关键词： radio astronomy instrumentation methods and techniques instrumentation:miscellaneous

Timing and Single-pulse Study of Pulsar J1909+0122 Discovered by CRAFTS

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Research in astronomy and Astrophysics 2023年第8期23卷 319-331页

作者： Yutong Chen Pei Wang Di Li Erbil Gügercinoğlu Rushuang Zhao Lingqi Meng Jianping Yuan Jiarui Niu Weiwei Zhu Yi Feng Chenchen Miao Chenhui Niu Qingdong Wu Na Wang Shen Wang Xiaoyao Xie Mengyao Xue Jumei Yao Mao Yuan Shanping You Xuhong Yu Youling Yue Jie Zhang Junshuo Zhang Lei Zhang Yabiao Wang Zhenye Gan Yuxi Li Zhongyi Sun Chengjie Wang National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute for Frontiers in astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China guizhou Normal University Guiyang 550001China Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China College of Physical Science and Technology Central China Normal UniversityWuhan 430079China Fudan University Shanghai 200443China Qilu Normal University Jinan 250200China Tencent Youtu Lab Shanghai 200233China

We report the discovery of PSR J1909+0122 by the Five-hundred-meter Aperture Spherical radio Telescope(FAST)as part of the Commensal radio astronomy FAST *** J1909+0122 has a spin period of 1.257 s and a dispersion measure of 186.2 pc cm^(-3).The averaged pulse profile shows two distinct *** performed a single-pulse study based on a one-hour observation at 1.25 GHz on 2021 August *** used a threshold of 5σ_(ep) to measure the nulling fraction(NF)as 63%±1.5%.The longitude-resolved fluctuation spectra and fast Fourier transform spectra of the binary sequences revealed the quasi-periodicity of nulling with a period of 30 rotation *** examined the reliability of the periodicity by comparing it to random noise *** NF,E,and modulation periodicity P_(M) of PSR J1909+0122 were compared with other periodic nulling pulsars,showing that the source of J1909+0122 has the second largest NF in the ***-term timing observations over six months were used to derive the phase-connected ephemeris of this *** measured P and P values disfavor dipolar geometry for polar gap models,and the prediction for a space-charge-limited flow model in the case of inverse Compton scattering is only just above the death *** this work,PSR J1909+0122 has revealed possible correlations between nulling behavior and pulsar properties,which will help to shed light on the pulsar emission mechanism and its temporal evolution in future observations.

关键词： (stars:)pulsars general-(stars:)pulsars individual(PSR J1909+0122)-stars neutron

First-principle study on the electronic structure of stressed CrSi_2

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Science China(Physics,Mechanics & astronomy) 2009年第1期52卷 76-81页

作者： ZHOU ShiYun1,2, XIE Quan1, YAN WanJun1 & CHEN Qian1 1 College of Electronic Science & Information Technology, guizhou University, Guiyang 550025, China 2 Department of Physics, Anshun College, Anshun 561000, China College of Electronic Science & Information Technology Guizhou University Guiyang China Department of Physics Anshun College Anshun China

The electronic structure of stressed CrSi2 was calculated using the first-principle methods based on plane-wave pseudo-potential theory. The calculated results showed that, under the uniaxial compression, the energy level of CrSi2 shifted toward high energy and its energy gap became wider with the increasing uniaxial stress, while the gap became narrower under the negative uniaxial stress. When the negative uniaxial stress was up to -18.5 GPa, CrSi2 was converted into a direct-gap semiconductor with the band gap of 0.32 eV.

关键词： CrSi2 first-principles stress electronic structure

First-principles study on the electronic structure and optical properties of CrSi_2

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Science China(Physics,Mechanics & astronomy) 2009年第1期52卷 46-51页

Using the first principle methods based on the plane-wave pseudo-potential theory, band structure, density of states and optical properties of CrSi2 were studied. The calculation of band structure shows that CrSi2 is an indirect semiconductor whose band gap is 0.353 eV. Density of states is mainly composed of 3d electron of Cr and 3p electron of Si. Dielectric function, refractive index, reflectivity, and absorption coefficient of CrSi2 are also calculated. The calculation results of optical properties are in agreement with the experiments.

关键词： CrSi2 electronic structure optical properties first principles