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Nuclear liquid-gas phase transition within a Brueckner-Hartree-Fock approach

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Chinese Physics C 2022年第11期46卷 231-237页

作者： Jing Zhang Hong-Ming Liu Zeng-Hua Li G.F.Burgio H.-J.Schulze Institute of Modern Physics Key Laboratory of Nuclear Physics and Ion-beam Application(MOE)Fudan UniversityShanghai 200433China INFN Sezione di Catania Dipartimento di Fisica e AstronomiaUniversitàdi CataniaVia S.Sofia 64I-95123 CataniaItaly

The critical parameters of the liquid-gas phase transition of symmetric nuclear matter are computed using the Brueckner-Hartree-Fock method at finite temperature by employing different realistic nucleon-nucleon *** effects on single-particle potentials,defect functions,and three-body forces are discussed in *** obtained from the full procedure and frozen-correlations approximation are *** find critical temperatures of approximately 14 to 19 MeV and critical densities in the range of 0.05 to 0.08fm^(-3),depending on the interactions employed.

关键词： nuclear liquid-gas phase transition Brueckner-Hartree-Fock approach symmetric nuclear matter

Resolution-dependent subsonic non-thermal line dispersion revealed by ALMA

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Research in Astronomy and Astrophysics 2021年第1期21卷 238-246页

作者： Nan-Nan Yue Di Li Qi-Zhou Zhang Lei Zhu Jonathan Henshaw Diego Mardones Zhi-Yuan Ren National Astronomical observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Harvard-Smithsonian Center for Astrophysics 60 Garden StreetCambridgeMA 02138USA NAoC-UKZN Computational Astrophysics Centre University of Kwa Zulu-NatalDurban 4000South Africa Chinese Academy of Sciences South America Center for Astronomy China-Chile Joint Center for AstronomyCamino EI Observatorio#1515Las CondesSantiagoChile Max-Planck Institut fur Astronomie Konigstuhl 17D.69117 HeidelbergGermany departameto de astronomia Universidad de ChileCasilla 36-DSantiagoChile

We report here Atacama Large Millimeter/submillimeter Array(ALMA)N2H+(1-0)images of the orion Molecular Cloud 2 and 3(oMC-2/3)with high angular resolution(3"or 1200 au)and high spatial dynamic *** a dataset from the ALMA main array,Atacama Compact Array(ACA),Nobeyama 45-m Telescope and Very Large Array(VLA)(providing temperature measurement on matching scales),we find that most of the dense gas in oMC-2/3 is subsonic(σQNT/cs=0.62)with a mean line width(△v)of 0.39 kms-1 full width at half maximum(FWHM).This is markedly different from the majority of previous observations of massive star-forming *** contrast,line widths from the Nobeyama Telescope are transonic at 0.69 km s-1(σNT/cs=1.08).We demonstrated that the larger line widths obtained by the single-dish telescope arose from unresolved sub-structures within their respective *** dispersions from larger scalesσls(as traced by the Nobeyama Telescope)can be decomposed into three components such thatσls2=σss2+σbm2+σrd2,where small-scaleσss is the line dispersion of each ALMA beam,bulk motionσbm is dispersion between peak velocity of each ALMA beam andσrd is the residual *** decomposition,though purely empirical,appears to be robust throughout our data *** supersonic line widths,commonly found in massive molecular clouds,are thus likely due to the effect of poor spatial *** observed non-thermal line dispersion(sometimes referred to as’turbulence’)transits from supersonic to subsonic at~0.05 pc scales in the oMC-2/3 *** transition could be commonly found with sufficient spatial(not just angular)resolution,even in regions with massive young clusters,such as the orion molecular clouds studied here.

关键词： stars:formation ISM:clouds ISM:molecules ISM:kinematics and dynamics

The relationship between the radio core-dominance parameter and spectral index in different classes of extragalactic radio sources(Ⅱ)

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Research in Astronomy and Astrophysics 2019年第5期19卷 75-90页

作者： Zhi-Yuan Pei Jun-Hui Fan denis Bastieri Utane Sawangwit Jiang-He Yang Center for Astrophysics Guangzhou University Astronomy Science and Technology Research Laboratory of department of Education of Guangdong Province Dipartimento di Fisica e astronomia "G.Galilei" Universit`a di Padova Istituto Nazionale di Fisica Nucleare National Astronomical Research Institute of Thailand (NARIT) department of Physics and Electronics Science Hunan University of Arts and Science

Active galactic nuclei(AGNs) can be divided into two major classes, namely radio-loud and radio-quiet AGNs. A small subset of the radio-loud AGNs is called blazars, which are believed to be unified with Fanaroff-Riley type Ⅰ/Ⅱ(FRI/Ⅱ) radio galaxies. Following our previous work(Fan et al.), we present a sample of 2400 sources with measured radio flux densities of the core and extended components. The sample contains 250 BL Lacs, 520 quasars, 175 Seyferts, 1178 galaxies, 153 FRI or FRⅡ galaxies and 104 unidentified sources. We then calculate the radio core-dominance parameters and spectral indices, and study their relationship. our analysis shows that the core-dominance parameters and spectral indices are quite different for different types of sources. We also confirm that the correlation between core-dominance parameter and spectral index exists for a large sample presented in this work.

关键词： galaxies:active-galaxies galaxies:jets-quasars:general

Strain Sensitivity Enhancement in Suspended Core Fiber Tapers

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Photonic Sensors 2013年第2期3卷 118-123页

作者： Ricardo M. ANDRE Susana o. SILVA Martin BECKER Kay SCHUSTER M. RoTHARDT H. BARTELT Manuel B. MARQUES orlando FRAZAo INESC Porto Rua do Campo Alegre 687 4169-007 Porto Portugal departamento de Fisica e astronomia da Faculdade de Ciencias da Universidade do Porto Rua do Campo Alegre 687 4169-007 Porto Portugal PHT Institute for Photonic Technology Jena Albert-Einstein-Str. 9 07745 Jena Germany

Suspended core fiber tapers with different cross sections （with diameters from 70μm to 120 μm） are produced by filament heating. Before obtaining the taper, the spectral behavior of the suspended core fiber is a multimode interference structure. When the taper is made, an intermodal interference between a few modes is observed. This effect is clearly visible for low taper core dimensions. Since the core and cladding do not collapse, two taper regions exist, one in the core and the other in the cladding. The cladding taper does not affect the light transmission, only the core is reduced to a microtaper. The spectral response of the microtaper based-suspended core fiber is similar to a beat of two interferometers. The strain is applied to the microtaper, and with the reduction in the transverse area, an increase in sensitivity is observed. When the taper is immersed in a liquid with a different index of refraction or subjected to temperature variations, no spectral change occurs.

关键词： optical fiber sensor taper microstructured fiber

Mean-field effects on matter and antimatter elliptic flow

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Nuclear Science and Techniques 2013年第5期24卷 132-139页

作者： Ko Cheming CHEN Liewen GRECo Vincenzo LI Feng LIN Ziwei PLUMARI Salvatore SoNG Taesoo XU Jun Cyclotron Institute and department of Physics and Astronomy Texas A & M UniversityCollege Station department of Physics Shanghai Jiao Tong University Dipartimento di Fisica e astronomia Universitá di CataniaVia S.Sofia 64 department of Physics East Carolina UniversityC-209 Howell Science ComplexGreenville Shanghai Institute of Applied Physics Chinese Academy of Sciences

We report our recent work on mean-field potential effects on the elliptic flows of matters and antimatters in heavy ion collisions leading to the production of a baryon-rich *** the framework of a multiphase transport(AMPT) model that includes both initial partonic and final hadronic interactions,we have found that including mean-field potentials in the hadronic phase leads to a splitting of the elliptic flows of particles and their antiparticles,providing thus a plausible explanation of the different elliptic flows between p and anti-p,K+and K-,and π+ and π- observed by the STAR Collaboration in the Beam Energy Scan(BES) program at the Relativistic Heavy Ion Collider(RHIC).Using a partonic transport model based on the Nambu-Jona-Lasinio(NJL) model,we have also studied the effect of scalar and vector mean fields on the elliptic flows of quarks and antiquarks in these *** quarks and antiquarks at hadronization to hadrons via the quark coalescence model,we have found that the elliptic flow differences between particles and antiparticles also depend on the strength of the quark vector coupling in baryon-rich quark-gluon plasma,providing thus the possibility of extracting information on the latter's properties from the BES program at RHIC.

关键词：椭圆流平均场反物质强子相互作用重离子碰撞重离子对撞机输运模型 RHIC

e-VLBI observations of GRB 080409 afterglow with an Australasian radio telescope network

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Research in Astronomy and Astrophysics 2016年第11期16卷 1-6页

作者： Aquib Moin Philip G. Edwards Steven J. Tingay Chris J. Phillips Anastasios K. Tzioumis Shaun W. Amy Tao An Mamoru Sekido Zhong-Xiang Wang Physics department United Arab Emirates University RO. Box 15551 A1-Ain United Arab Emirates Shanghai Astronomical observatory Chinese Academy of Sciences Shanghai 200030 China International Centre for Radio Astronomy Research Curtin University Bentley WA Australia CSIRo Astronomy and Space Science P.O. Box 76 Epping NSW 2121 Australia Kashima Space Research Center National Institute of Information and Communications Technology (NICT) 893-1 Hirai Kashima 314-0014 Ibaraki Japan Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing 210008 China osservatorio di Radio astronomia Istituto Nazionale di Astrofisica Italy

Transcontinental e-VLBI observations were conducted in June 2008 with telescopes in Australia, China and Japan. detections were made of the radio-loud quasar PKS B0727-115, which shows superlu- minal motion, and the intra-day variable quasar PKS B0524＋034. The latter source was used as a phase reference calibrator for observations at the position of the gamma-ray burst GRB 080409, for which an upper limit to the radio emission is set. Australia Telescope Compact Array data were also used to derive a limit on the radio flux density of the GRB afterglow. These observations demonstrate the capability to form a large Australasian radio telescope network for e-VLBI, with data transported and processed in realtime over high capacity networks. This campaign represents the first step towards more regular e-VLBI observations in this region.

关键词： techniques: interferometric -- galaxies: active -- gamma rays: bursts

Interferometer Based on a D-shape Chaotic optical Fiber for Measurement of Multiparameters

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Photonic Sensors 2012年第4期2卷 381-384页

作者： Susana SILVA Luis CoELHo Philippe RoY orlando FRAZAo INESC Porto Rua do Campo Alegre 687 4169-007 Porto Portugal and Dept. de Fisica e Astronomia da Faculdade de Ciencias da Universiclacle do Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Xlim UMR 6172 CNRS-University of Limoges 123 Avenue Albert Thomas 87060 Limoges Cedex France

An interferometer based on a D-shape chaotic optical tiber tor measurement ot multiparameters was proposed. The sensing structure relied on a D-shape fiber section spliced in between two singlemode fibers and interrogated in transmission. The optical spectrum was composed by multiple interference loss peaks, which were sensitive to the refractive index, temperature and strain-maximum sensitivities of 95.2 nm/RIU, 10.5 pm/℃ and -3.51 pm/με, respectively, could be achieved.

关键词： optical fiber sensors interferometer chaotic fiber

Radio core dominance of Fermi/LAT-detected AGNs

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Science China(Physics,Mechanics & Astronomy) 2020年第5期63卷 105-123页

作者： ZhiYuan Pei JunHui Fan denis Bastieri JiangHe Yang HuBing Xiao Diparimento di Fisica e astronomia“G.Galilei”.Universita di Padova Padova 1-35131Italy Istituto Nazionale di Fisica Nucleare Sezione di PadovaPadova 1-35131Italy Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of department of Education of Guangdong Province Guangzhou 510006China department of Physics and Electronics Science Hunan University of Arts and ScienceChangde 415000China

We present a sample of 4388 AGNs with available radio core-dominance parameters—defined as the ratio of the core flux densities to the extended ones, R = S_(core)/S_(ext).—which includes 630 Fermi-detected AGNs from the fourth source catalog(4FGL) of the Fermi Large Area Telescope(Fermi/LAT);the rest are non-Fermi-detected AGNs. In our sample, 584 blazars are Fermi-detected and 1310 are not. The sample also contains other subclasses, such as Seyferts, Fanaroff-Riley I/II galaxies, and normal *** investigate various properties of the Fermi-detected and non-Fermi-detected AGNs by using core-dominance parameters,capitalizing on a previous study which showed that R is a good indicator of beaming. We then calculate radio spectral indices for the whole sample, and adopt γ-ray-photon indices for the Fermi AGNs from the 4FGL catalog to discuss the properties of different subclasses. We obtain a relation between the core-dominance parameters and the radio spectral indices for both Fermi and non-Fermi sources, assuming a two-component model in the radio band. our previous study ruled out the assumption that the core-dominance parameters and radio spectral indices are quite different for different AGN subclasses. This holds not only for Fermi sources but also for non-Fermi sources. In particular, R is, on average, greater for the former AGNs than for the *** this study, we enlarge our sample with available values of R to 4388 AGNs, and the obtained conclusions are consistent with our previous study. We assume that the same two-component model holds for the γ-ray band as for the radio band, and therefore,adopt the same relation between the core-dominance parameters and the γ-ray-photon indices for Fermi AGNs. our fitting results indicate that the γ-ray emissions of Fermi blazars originate mainly from the jet, and therefore, we conclude that the Fermi blazars are beamed.

关键词： active galactic nuclei(AGNs) quasars γ-rays

The spin-isospin decomposition of the nuclear symmetry energy from low to high density

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Chinese Physics C 2020年第5期44卷 114-118页

作者： Wenmei Guo M.Colonna V.Greco U.Lombardo H.-JSchulze department of Physics Anhui Normal UniversityWuhu 241000China Laboratori Nazionali del Sud(INFN) Via S.Sofia 6295123 CataniaItaly Dipartimento di Fisica e astronomia Via S.Sofia 6495123 CataniaItaly INFN Sezione di CataniaVia S.Sofia 6295123 CataniaItaly

The energy per particle BA in nuclear matter is calculated up to high baryon density in the whole isospin asymmetry range from symmetric matter to pure neutron *** results,obtained in the framework of the Brueckner-Hartree-Fock approximation with two-and three-body forces,confirm the well-known parabolic dependence on the asymmetry parameterβ=(N?Z)/A(β^2 law)that is valid in a wide density *** investigate the extent to which this behavior can be traced back to the properties of the underlying interaction,aside from the mean field approximation,the spin-isospin decomposition of BA is *** indications suggest that theβ^2 law could be violated at higher densities as a consequence of the three-body *** raises the problem that the symmetry energy,calculated according to theβ^2 law as a difference between BA in pure neutron matter and symmetric nuclear matter,cannot be applied to neutron *** should return to the proper definition of the nuclear symmetry energy as a response of the nuclear system to small isospin imbalance from the Z=N nuclei and pure neutron matter.

关键词： symmetry energy nuclear interaction spin-isospin decomposition nuclear matter