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The “Bi-drifting” Subpulses of PSR J0815+0939 Observed with the Fivehundred-meter Aperture Spherical Radio Telescope

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Research in Astronomy and Astrophysics 2022年第2期22卷 195-203页

作者： Lun-Hua Shang jun-Tao Bai Shi-jun Dang qi-jun zhi School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China

We report the "Bi-drifting" subpulses observed in PSR J0815+0939 using the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The observation at band from 1050 to 1450 MHz is evenly divided into two bands, i.e., the bands at center frequencies of 1150 and 1350 MHz. The mean pulse profiles and the "Bi-drifting"subpulses at these two bands are investigated. It is found that the pulse profiles at these two frequencies show four emission components, and the peak separations between four emission components decrease with the increase of frequency. In addition, the ratio of peak intensity of each component to the intensity of component Ⅳ at 1150 MHz is larger than that at 1350 MHz. We carry out an analysis of the longitude-resolved fluctuation spectrum and twodimensional fluctuation spectrum for each emission component, and find that the P3 of components Ⅰ,Ⅱ and Ⅲ is about 10.56, 10.57 and 10.59 s at 1150 and 1350 MHz. However, the reliable measurements of P3 of component IV and P2 for these four components were not obtained due to the low signal-to-noise ratio of observation *** pulse energy distributions at frequencies 1150 and 1350 MHz are presented, and it is found that no nulling phenomenon has been found in this pulsar. With our observation from the FAST, the "Bi-drifting" subpulse phenomenon of PSR J0815+0939 is expanded from 400 to 1350 MHz, which is helpful for the relevant researchers to test and constrain the pulsar emission model, especially the model of "Bi-drifting" subpulse.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(PSR J0815+0939) radiation mechanisms:nonthermal

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Synthesis and study of MPNS/SMA nano-composite tanning agent

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Chinese Chemical Letters 2008年第4期19卷 435-437页

作者： Hui Pan Mei qi zhi jun Zhang Laboratory of Special Functional Material Henan UniversityKaifeng 475004PR China

The radical polymerization of maleic anhydride（MA）,styrene（ST）with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was *** methacryloxypropyl nano-sized silica（MPNS）was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in *** structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and ***,it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in *** was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.

关键词： Nano-composite Tanning agent Polymerization Leather

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Optimal quantum parameter estimation of two-qutrit Heisenberg XY chain under decoherence

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Chinese Physics B 2017年第1期26卷 145-150页

作者： Hong-ying Yang qiang Zheng qi-jun zhi School of Physics and Electronics Guizhou Normal University Guiyang 550001 China School of Mathematics Guizhou Normal University Guiyang 550001 China

Adopting the Milburn decoherence model, we investigate the performance of quantum Fisher information of the twoqutrit isotropic Heisenberg XY chain under decoherence. We find that the quantum Fisher information with respect to the decoherence rate and the magnetic field decreases exponentially in the long-time limit, which significantly reduces the precision of optimal quantum estimation. We also show that with the increase of the decoherence rate or the magnetic field,the QFIs go down considerably. Furthermore, we find that the precision of optimal quantum estimation can be enhanced by the entanglement in the input state.

关键词： intrinsic decoherence quantum Fisher information spin chain

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Time-resolved Spectral Properties of Fermi-GBM Bright Long Gamma-Ray Bursts

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Research in Astronomy and Astrophysics 2024年第2期24卷 58-73页

作者： Wan-Kai Wang Wei Xie zhi-Fu Gao Shuo Xiao Ai-jun Dong Bin Zhang qi-jun zhi Department of Astronomy School of Physics and Electronic ScienceGuizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy Data Processing Guizhou Normal UniversityGuiyang 550001China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China

The prompt emission mechanism of gamma-ray bursts(GRBs)is still unclear,and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical *** performed a detailed time-resolved spectral analysis of 78 bright long GRB samples detected by Fermi/Gamma-ray Burst Monitor.A total of 1490 spectra were obtained and their properties were studied using a typical Band-shape ***,the parameter distributions of the time-resolved spectrum are given as follows:the low-energy spectral indexα~-0.72,high-energy spectral indexβ~2.42,the peak energy E_(p)~221.69 keV,and the energy flux F~7.49×10^(-6)erg cm^(-2)s^(-1).More than 80%of the bursts exhibit the hardest low-energy spectral indexα_(max),exceeding the synchrotron limit(-2/3).Second,the evolution patterns of a and E_(p)were statistically *** results show that for multi-pulse GRBs the intensity-tracking pattern is more common than the hard-to-soft pattern in the evolution of both E_(p)andα.The hard-to-soft pattern is generally shown in single-pulse GRBs or in the initial pulse of multi-pulse ***,we found a significant positive correlation between F and E_(p),with half of the samples exhibiting a positive correlation between F andα.We discussed the spectral evolution of different radiation *** diversity of spectral evolution patterns indicates that there may be more than one radiation mechanism occurring in the GRB radiation process,including photo spheric radiation and synchrotron ***,it may also involve only one radiation mechanism,but more complicated physical details need to be considered.

关键词： (stars:)gamma-ray burst general-methods statistical-methods data analysis

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Effects of the momentum dependence of nuclear symmetry potential on pion observables in Sn+Sn collisions at 270 MeV/nucleon

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Nuclear Science and Techniques 2022年第12期33卷 147-158页

作者： Gao‑Feng Wei Xin Huang qi‑jun zhi Ai‑jun Dong Chang‑Gen Peng Zheng‑Wen Long School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China College of Physics Guizhou UniversityGuiyang 550025China

Within a transport model,we investigated the effects of the momentum dependence of the nuclear symmetry potential on the pion observables in central Sn+Sn collisions at 270 MeV/*** this end,the quantity U^(∞)_(sym)(ρ_(0))(i.e.,the value of the nuclear symmetry potential at the saturation densityρ_(0) and infinitely large nucleon momentum)was used to characterize the momentum dependence of the nuclear symmetry *** a certain L(i.e.,the slope of the nuclear symmetry energy at(ρ_(0))),the characteristic parameter U^(∞)_(sym)(ρ_(0))of the symmetry potential significantly affects the production of−and+and their pion ***,by comparing the charged pion yields,pion ratios,and spectral pion ratios of the theoretical simulations for the reactions ^(108) Sn+^(112) Sn and ^(132)Sn+^(124)Sn with the corresponding data in the SRIT experiments,we found that our results favor a constraint on U^(∞)_(sym)(ρ_(0))(i.e.,−160_(−9)^(+18) MeV),and L is also suggested within a range of 62.7 MeV

关键词： Nuclear symmetry potential Momentum dependence Symmetry energy

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Examination of an isospin-dependent single-nucleon momentum distribution for isospin-asymmetric nuclear matter in heavy-ion collisions

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Nuclear Science and Techniques 2020年第7期31卷 85-95页

作者： Gao-Feng Wei qi-jun zhi Xin-Wei Cao Zheng-Wen Long School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China School of Mechanical and Material Engineering Xi’an University of Arts and SciencesXi’an 710065China College of Physics Guizhou UniversityGuiyang 550025China

Within a transport model using nucleon momentum profiles as the input from a parameterized isospin-dependent single-nucleon momentum distribution,with a high momentum tail induced by short-range correlations,we employ197 Au+197 Au collisions at 400 MeV/nucleon to examine the effects of the short-range correlations on the pion and flow observables in probing the nuclear symmetry *** investigate how reliable this isospin-dependent single-nucleon momentum distribution is and determine the corresponding parameter *** from the significant effects of the short-range correlations on the pion and flow observables that are observed,we also find that the theoretical simulations of the197 Au+197 Au collisions with this momentum distribution using two sets of parameters,extracted from the experimental analysis and the self-consistent Green’s function prediction,can reproduce the neutron ellipticflows of the FOPI-LAND experiment and the pà=ptratios of the FOPI experiment,respectively,under the symmetry energy setting in a particular ***,we conclude that this parameterized isospin-dependent single-nucleon momentum distribution is reliable for isospin-asymmetric nuclear ***,two sets of parameters extracted from both the experimental analysis and the selfconsistent Green’s function prediction cannot be excluded according to the available experimental information at present.

关键词： momentum distribution asymmetric

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CSS J075415.6+191052 and NW Leo: Two Contact Binaries at Different Evolutionary Stages

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Research in Astronomy and Astrophysics 2022年第2期22卷 118-127页

作者： Xu-Dong Zhang Sheng-Bang qian Er-Gang Zhao qi-jun zhi Ai-jun Dong Bin Zhang School of Physics and Electronic Science Guizhou Normal University550025 GuiyangChina Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025 GuiyangChina Yunnan Observatories Chinese Academy of Sciences(CAS)650216 KunmingChina University of Chinese Academy of Sciences(UCAS) 100049 BeijingChina

Multi-color light curves of CSS J075415.6+191052 and NW Leo are presented and the photometric solutions suggest that CSS J075415.6+191052 is an A-subtype contact binary with low mass ratio(q = 0.178) while NW Leo has a high mass ratio(q = 0.707). For CSS J075415.6+191052, the RI light curves show weakening around the left shoulder of the secondary minimum, which indicates that there may be a dark spot on the secondary component. However, the light curves of BV bands are totally symmetric. It is unreasonable if the dark spot is caused by magnetic activity or mass transfer between the two components. Therefore, weakening of the light curves in this contact binary is caused by something else. A possible explanation is mass transferring from the primary component to the common convective envelope through the inner Lagrangian point, and this part of the mass, for some reason, weakens the RI bands of light from the secondary component. O-C analysis of NW Leo reveals a cyclic period change with a modulation period of 4.7 yr, which may be caused by the light travel time effect of a third body. The positions of CSS J075415.6+191052 and NW Leo in the P–J′_(orb)diagram indicate that CSS J075415.6+191052 mainly abides by the angular momentum loss theory while NW Leo is dominated by the thermal relaxation oscillation theory.

关键词： (stars:)binaries:eclipsing stars:evolution stars:individual(CSS J075415.6+191052 NW Leo)

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Luminosity of a radio pulsar and its new emission death line

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Research in Astronomy and Astrophysics 2020年第11期20卷 325-332页

作者： qing-Dong Wu qi-jun zhi Cheng-Min Zhang De-Hua Wang Chang-qing Ye School of Physics and Electronic Sciences Guizhou Normal UniversityGuiyang 550001China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guiyang 550001China University of Chinese Academy of Sciences Beijing 100049China

We investigated the pulsar radio luminosity(L),emission efficiency(ratio of radio luminosity to its spin-down powerE),and death line in the magnetic field(B)versus spin period(P)*** found that the dependence of pulsar radio luminosity on its spin-down power(L-E)is very weak,shown as L^E0.06,which deduces an equivalent inverse correlation between emission efficiency and spin-down power asξ~***,we examined the distributions of radio luminosity of millisecond and normal pulsars and found that for the similar spin-down powers,the radio luminosity of millisecond pulsars is about one order of magnitude lower than that of the normal *** analysis of pulsar radio flux suggests that these correlations are not due to a selective effect but are intrinsic to the pulsar radio emission *** radio radiations may be dominated by the different radiation *** cutoff phenomenon of currently observed radio pulsars in B-P diagram is usually referred as the"pulsar death line",which corresponds toE≈1030 erg s-1 and is obtained by the cut-off voltage of electron acceleration gap in the polar cap model of pulsar proposed by Ruderman and ***,this death line can be inferred by the actual observed pulsar flux S≥1 mJy and 1 kpc distance,together with the maximum radio emission efficiency of 1%.However,the observation data show that the 37 pulsars pass over the death line,including the recently observed two pulsars with long periods of 23.5 s and 12.1 s,which violate the prediction of the polar cap *** present,the actual observed pulsar flux can reach0.01 mJy by FAST *** will arise the observational limit of spin-down power of pulsars as low as E˙≈1028 erg *** means that the new death line is downward shifted two orders of magnitude,which might be favorably referred as the"observational limit–line".Accordingly,the pulsar theoretical model for the cut-off voltage of gap should be heavily modified.

关键词： stars neutron pulsars general stars fundamental parameters

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NSVS 01286630:a detached binary with a close-in companion

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Research in Astronomy and Astrophysics 2018年第9期18卷 123-132页

作者： Bin Zhang Sheng-Bang qian Nian-Ping Liu Wen-Ping Liao Li-Ying Zhu Ai-jun Dong qi-jun zhi Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China

New photometric observations of NS VS 01286630 were performed and two sets of fourcolor（B, V, Rc, Ic） light curves（LCs） were obtained. Using the 2013 version of the Wilson-Devinney（W-D） code, we analyzed these data. The photometric solutions reveal that NS VS 01286630 is an active detached eclipsing binary（EB） with a high orbital inclination（nearly 90°）. Remarkably, the temperature of the primary component（the hotter star） is higher than the secondary one, but the value of mass ratio q（M2/M1）for NS VS 0128663 is more than 1, which can be explained in that the surface of the secondary component of NSVS 01286630 is covered with big cool starspots. Based on our new CCD mid-eclipse times and the data published until now, variations in the mid-eclipse times were reanalyzed in detail using a weighted least-squares method. It is discovered that the（O-C） diagram of the system shows a cyclic oscillation with a period of 3.61 yr and an amplitude of 0.001 d. The cyclic variation may be caused by the light-travel time effect（LTTE） due to the presence of a third companion, whose mass we calculated as M3 sin（i3） =0.11 M（⊙）. The third body may affect the orbital evolution of the central binary system by transferring angular momentum.

关键词： stars binaries close- stars binaries eclipsing-stars individual (NSVS 01286630)

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β^--Decay Half-Lives for Waiting Point Nuclei Around N=126

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Communications in Theoretical Physics 2019年第3期71卷 293-297页

作者： Ji-Lin You qing-Dong Wu Xiao-Ping Zhang qi-jun zhi School of Physics and Electronic Sciences Guizhou Normal University Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal University State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and Technology

We have systematically analyzed the experimental β--decay half-lives of waiting point heavy nuclei around neutron number N = 126. A new set of parameters for the exponential formula of β^--decay half-lives is proposed. The forbidden transition effects are included in the new set of parameters self-consistently. Theoretical β^--decay half-lives of nuclei around N = 126 are compared with recent theoretical results and experimental data. It is found that the new theoretical results are in better agreement with experimental data. The unknown β^--decay half-lives of some nuclei in this region are predicted for studies on nuclear structure far from stability and the nucleosynthesis in stars.

关键词： β^--decay half-lives waiting point nuclei nucleosynthesis

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