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Late-time photometry of two nearby type II-P supernovae: 2004dj and 2004et

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Research in Astronomy and Astrophysics 2009年第7期9卷 783-790页

作者： Tian-Meng Zhang Xiao-Feng Wang Xu Zhou Jun Ma Zhao-Ji jiang jiang-hua wu Zhen-Yu wu Stephane Basa NationalAstronomicalObservatories Chinese Academy of Sciences Beijing 100012 China Observatoire Astronomique de Marseille-Provence 38 rue Fric Joliot-Curie 13388 Marseille Cedex 13 France Physics Department and Tsinghua Center for Astrophysics （THCA） Tsinghua University Beijing 100084 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Department of Astronomy University of California Berkeley CA 94720-3411 USA

We present late-time photometry for two bright type II-P supernovae （SNe） 2004dj and 2004et, extending over 400 d after the explosion, which are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. Although these two SNe II-P exhibit similar photometric evolution at earlier times, they diverge during the nebular phase. SN 2004dj shows a slow late-time decline rate with - 0.7 ±0.1 mag （100d）^-1 during the period ranging from t ≈ 200 - 300 d after the explosion, while SN 2004et shows a much faster decline rate at a comparable phase, e.g., 1.3 ± 0.1 mag （100d）^-1. The steeper decay rate seen in SN 2004et is likely due to dust formation in the explosion ejecta. Based on intermediate-band photometry, we derived the evolution of the feature lines [e.g., Hα] of SNe 2004dj and 2004et which are similar in flux at comparable phases but perhaps with significantly different decay rates. The origin of the observed variations in the continuum and the feature lines is briefly discussed.

关键词： supernovae general - supernovae: individual (SN 2004dj SN 2004et) -techniques: photometric

Multicolor photometry of the galaxy cluster A98: substructures and star formation properties

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Research in Astronomy and Astrophysics 2010年第1期10卷 1-21页

作者： Li Zhang Qi-Rong Yuan Xu Zhou Zhao-Ji jiang Yan-Bin Yang Jun Ma jiang-hua wu Zhen-Yu wu Department of Physics Nanjing Normal University Nanjing 210046 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

An optical photometric observation with the Beijing-Arizona-Taiwan- Connecticut （BATC） multicolor system is carried out for A98 （z =0.104）, a galaxy cluster with two large enhancements in X-ray surface brightness. Spectral energy distributions （SEDs） covering 15 intermediate bands are obtained for all sources detected down to V - 20 mag in a field of 58′× 58′. After star-galaxy separation with colorcolor diagrams, a photometric redshift technique is applied to the galaxy sample for further membership determination. The color-magnitude relation is taken as a further restriction of the early-type cluster galaxies. As a result, a list of 198 faint member galaxies is achieved. Based on the newly generated sample of member galaxies, the dynamical substructures, A98N, A98S, and A98W, are investigated in detail. A separate galaxy group, A98X, is also found to the south of the main concentration of A98, which is gravitationally unbound to A98. For 74 spectroscopically confirmed member galaxies, the environmental effect on the star formation history is investigated. The bright galaxies in the core region are found to have shorter time scales of star formation, longer mean stellar ages, and higher interstellar medium metallicities, which can be interpreted in the context of the hierarchical cosmological scenario.

关键词： galaxies clusters individual (A98) - galaxies distances and redshifts - galaxies kinematics and dynamics - galaxies evolution - methods data analysis

Variable stars in the field of open cluster NGC 2126

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Research in Astronomy and Astrophysics 2009年第7期9卷 791-802页

作者： Shun-Fang Liu Zhen-Yu wu Xiao-Bin Zhang jiang-hua wu Jun Ma Zhao-Ji jiang Jian-Sheng Chen Xu Zhou National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We report the results of a time-series CCD photometric survey of variable stars in the field of open cluster NGC 2126. In about a one square degree field covering the cluster, a total of 21 variable candidates are detected during this survey, of which 16 are newly found. The periods, classifications and spectral types of 14 newly discovered variables are discussed, which consist of six eclipsing binary systems, three pulsating variable stars, three long period variables, one RS CVn star, and one W UMa or δ Scuff star. In addition, there are two variable candidates, the properties of which cannot be determined. By a method based on fitting observed spectral energy distributions of stars with theoretical ones, the membership probabilities and the fundamental parameters of this cluster are determined. As a result, five variables are probably members of NGC 2126. The fundamental parameters of this cluster are determined as： metallicity to be 0.008 Z, age log（t） = 8.95, distance modulus （m - M）0 = 10.34 and reddening value E（B - V） = 0.55 mag.

关键词： open clusters: individual (NGC 2126) - stars: variables (general) - bina- ties: general

Multicolor photometry of the nearby galaxy cluster A119

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Research in Astronomy and Astrophysics 2012年第10期12卷 1381-1401页

作者： Jin-Tao Tian Qi-Rong Yuan Xu Zhou Zhao-Ji jiang Jun Ma jiang-hua wu Zhen-Yu wu Tian-Meng Zhang Hu Zou National Astronomical Observatories Chinese Academy of Sciences Beiiing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academyof Sciences Beijing 100012 China Department of Physics Nanjing Normal University Nanjing 210046 China Department of Astronomy Beijing Normal University Beijing 100875 China

This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 （z = 0.0442） with the Beijing-Arizona-Taiwan-Connecticut system of 15 intermediate bands. Within the BATC field of view of 58＇× 58＇, there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies （called sample I）. Based on the spectral energy distributions of 1376 galaxies brighter than iBATC ---- 19.5, the photometric redshift technique and the color-magnitude relation of early-type galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample （called sample II） of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynami- cally complex cluster with at least three prominent substructures in the central region within 1 Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidence for morphology or luminosity segrega- tions is found in either sample. With the PEGASE evolutionary synthesis model, the environmental effect on the properties of star formation is confirmed. Faint galaxies in the low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities in their interstellar medium, which is in agreement with the context of the hierarchical cosmological scenario.

关键词： galaxies: clusters: individual (A119)- galaxies: distances and redshifts-- galaxies: evolution-- galaxies: kinematics and dynamics-- methods: data analysis

Metal abundance and kinematical properties of the M81 globular cluster system

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Research in Astronomy and Astrophysics 2013年第4期13卷 399-410页

作者： Jun Ma Zhen-Yu wu Tian-Meng Zhang Song Wang Zhou Fan jiang-hua wu Hu Zou Cui-hua Du Xu Zhou Qi-Rong Yuan National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences Graduate University of Chinese Academy of Sciences Department of Astronomy Beijing Normal University College of Physical Sciences Graduate University of Chinese Academy of Sciences Department of Physics Nanjing Normal University

We present metal abundance properties of 144 globular clusters associated with M81. These globulars represent the largest globular cluster sample in M81 till now. Our main results are： the distribution of metallicities is bimodal, with metallicity peaks at [Fe/H] -1.51 and -0.58, and the metal-poor globular clusters tend to be less spatially concentrated than the metal-rich ones; the metal-rich globular clusters in M81 do not demonstrate a centrally concentrated spatial distribution like the metalrich ones in M31 do; like our Galaxy and M31, the globular clusters in M81 have a small radial metallicity gradient. These results are consistent with those obtained from a small sample of M81 globular clusters. In addition, this paper shows that there is evidence that a strong rotation of the M81 globular cluster system around the minor axis exists, and that rotation is present in the metal-rich globular cluster subsample, but the metal-poor globular cluster subsample shows no evidence of rotation. The most significant difference between the rotation of the metal-rich and metal-poor globular clusters occurs at intermediate projected galactocentric radii. Our results confirm the conclusion of Schroder et al. that M81＇s metal-rich globular clusters at intermediate projected radii are associated with a thick disk of M81.

关键词： galaxies: individual (M81) -galaxies: star clusters globular clusters:general

Old stellar population synthesis:new age and mass estimates for Mayall II = G1

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Research in Astronomy and Astrophysics 2009年第6期9卷 641-652页

作者： Jun Ma Richard de Grijs Zhou Fan Soo-Chang Rey Zhen-Yu wu Xu Zhou jiang-hua wu Zhao-Ji jiang Jian-Sheng Chen Kyungsook Lee Sangmo Tony Sohn National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Department of Physics ＆ Astronomy The University of Sheffield Hicks Building Hounsfield Road Sheffield S3 7RH UK Graduate University Chinese Academy of Sciences Beijing 100049 China Department of Astronomy and Space Science Chungnam National University Daejeon 305-764 Korea Center for Space Astrophysics Yonsei University Seoul 120-749 Korea California Institute of Technology MC 405-47 1200 E. California Boulevard Pasadena CA 91125

Mayall Ⅱ = G1 is one of the most luminous globular clusters （GCs） in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHKs 2MASS data, we construct the most extensive spectral energy distribution of G 1 to date, spanning the wavelength range from 1538 to 20 000A. A quantitative comparison with a variety of simple stellar population （SSP） models yields a mean age which is consistent with G1 being among the oldest building blocks of M31 and having formed within ～1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates （of order 10^7M⊙） indicate that GI is one of the most massive GCs in the Local Group. However, we speculate that the cluster＇s exceptionally high mass suggests that it may not be a genuine GC. Our results also suggest that G1 may contain, on average, （1.65±0.63） × 10^2L⊙ far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the adopted SSP model. In addition, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs that have similar accuracies as those from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.

关键词： galaxies individual (M31) -- galaxies star clusters -- galaxies stellar content

Distribution of nimodipine in brain following intranasal administration in rats

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Acta Pharmacologica Sinica 2004年第4期25卷 124-129页

作者： Qi-zhi ZHANG, Xin-guo jiang2, Chun-hua wu Department of Pharmaceutics, School ofPharmacy, Fudan University, Shanghai 200032, China Department of Pharmaceutics School of Pharmacy Fudan University 上海 200032

AIM: To determine whether nasally applied nimodipine (NM) could improve its systemic bioavailability and be transported directly from the nasal cavity to the brain. METHODS: NM was administered nasally, intravenously (iv), and orally to male Sprague-Dawley rats. At different times post dose, blood, cerebrospinal fluid (CSF), and brain tissue samples were collected, and the concentrations of NM in the samples were analyzed byHPLC. RESULTS: Oral systemic bioavailability of NM in rats was 1.17 %, nasal dosing improved bioavailibility to 67.4 %. Following intranasal administration, NM concentrations in olfactory bulb (OB) within 30 min post dose were found significant higher than in the other brain tissues. However, similar NM levels in different brain regions were observed after iv injection. AUC in CSF and OB from the nasal route was 1.26 and 1.39 fold compared with the iv route, respectively. The brain-to-plasma AUC ratios were significantly higher after nasal administration than after iv administration (P<0.01). CONCLUSION: Nasally administered NM could markedly improve the bioavailability and a fraction of the NM dose could be transported into brain via the olfactory pathway in rats.

关键词： intranasal administration nimodipine olfactory bulb olfactory pathways

Crystallization Kinetics and Melting Behavior of PA1010/Ether-based TPU Blends

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Chemical Research in Chinese Universities 2007年第3期23卷 370-373页

作者： ZHANG Shu-ling ZHAO Yan SUN Xiao-bo jiang Zhen-hua wu Zhong-wen WANG Gui-Bin Alan G. MacDiarmid Lab. College of Chemistry Jilin University Changchun 130012 P. R. China

Polyamide 1010 （PA1010）/thermoplastie poly （ether urethane） elastomer （ether-based TPU） blends were prepared via melt extrusion. The crystallization kinetics and melting behavior of PA1010/ether-based TPU blends were systematically investigated using differential scanning calorimetry. The crystallization kinetics results show that the addition of ether-based TPU hinders the crystallization of PA1010, and the hindrance effect increases with the increase of the concentration of ether-based TPU. Both pure PA1010 and PA1010/ether-based TPU blends exhibit double melting peaks in the process of nonisothermal crystallization. The double melting peaks change differently with the variation of cooling rate and blend composition. The cooling rate only influences the lower melting peak; however, the blend composition influences not only the lower melting peak but also the higher melting peak. The reason for the phenomenon must be the interaction between the two compositions.

关键词： Kinetics Melting point Nylon TPU Differential scanning calorimetry(DSC)

Clinical value of ^(18)F-FDG PET/CT in evaluation of hepatic vein,inferior vena cava and right atrium tumor thrombi in hepatocellular carcinoma:Initial results

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Nuclear Science and Techniques 2012年第3期23卷 169-175页

作者： SUN Long ZHAO Long LUO Zuoming jiang Maoqing wu hua Minnan PET Center and Department of Nulear Medicine No. 1 Hospital Affiliated to Xiamen University Xiamen 361003 China

In this paper,eleven consecutive hepatocellular carcinoma(HCC) patients with an embolus in the hepatic vein(HV),inferior vena cava(IVC)and right atrium(RA) were studied with 18F-FDG PET/CT and contrast enhanced *** correlated with final diagnosis,18F-FDG PET/CT and contrast enhanced CT was positive in 11 patients(100%),7 patients(63.6%),*** accuracy of PET/CT and contrast-enhanced CT were 100%,63.6%.Three cases with secondary blood thrombi in the distant IVC,which were confirmed by PET/CT,cannot be identified by contrast enhanced *** average survival was 3 months(range,1-12mo).The 12 months survival rate was 9.1%.Our results suggest that highly metabolic tumor thrombus in the HV,IVC and RA may be depicted on 18F-FDG PET/CT in HCC *** may discriminate between malignant and secondary benign blood thrombi.

关键词：肝细胞肝癌 PET 肝静脉 CT 临床应用心房评价价值