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Drifting bands of solar radio spikes

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chinese Science Bulletin 2008年第4期53卷 638-640页

作者： XU FuYing1,2& WU HongAo1,2 1 Purple Mountain Observatory,chinese academy of sciences,Nanjing 210008,China 2 national astronomical {3.,chinese academy of sciences,beijing 100012,China Purple Mountain Observatory Chinese Academy of Sciences Nanjing China national astronomical observatories Chinese Academy of Sciences Beijing China

The solar flare(1N/C5.3. occurred in NOAA 8742 on October 27,1999,and the accompanied complex radio burst was observed by the spectrometer with both high temporal(5 ms) and frequency(10 MHz) resolutions at Purple Mountain Observatory(PMO).It started at 04:27:42 UT,peaked at 04:28:42 UT and ended at 04:29:18 *** most significant feature of the event might be the sequential spikes in both time and frequency to form three slow drift bands over the frequency range of ～5 to ≥7.5 GHz with almost the same drift rate about 2.7 GHz/*** relative bandwidth for the individual spikes varied from 1.6% to 4.9%,typically 3.3..Based on electron cyclotron maser action driven by loss-cone anisotropy,the rare phenomena of slow drift band consisting of spikes were interpreted by spike source moving back and forth along the magnetic ***,the estimations of the narrow bandwidths of spike given by electron cyclotron maser theory coincided well with the observations.

关键词：太阳耀斑微波爆裂太阳活动天文学

Positions and Spectral Energy Distributions of 41 Star Clusters in M3.

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chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 197-206页

作者： Jun Ma, Xu Zhou, jian-Sheng Chen, Hong Wu, Zhao-Ji jiang, Sui-jian Xue and Jin Zhu{3. astronomical observatories, chinese academy of sciences, beijing 100012 national astronomical observatories Chinese Academy of Sciences Beijing 100012

We present accurate positions and multi-color photometry for 41 star clusters detected by Melnick & D'odorico in the nearby spiral galaxy M3. as a part of the BATC Color Survey of the sky in 13.intermediate-band filters from 3.00 to 10 000 A. The coordinates of the clusters are found from the HST Guide Star Catalog. By aperture photometry, we obtain the spectral energy distributions of the clusters. Using the relations between the BATC intermediate-band system and UBVRI broadband system, we derive their V magnitudes and B - V colors and find that most of them are blue, which is consistent with previous findings.

关键词： galaxies: individual (M3.) - galaxies: evolution - galaxies: star clusters

Spectroscopic study of globular clusters in the halo of M3. with the Xinglong 2.16 m telescope

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Research in Astronomy and Astrophysics 2011年第11期11卷 1298-1310页

作者： Zhou Fan1,2,Ya-Fang Huang1,2,Jin-Zeng Li1,2,Xu Zhou1,2,Jun Ma1,2,Hong Wu1,2,Tian-Meng Zhang1,2 and Yong-Heng Zhao1,2 1 national astronomical observatories,{3.,beijing 100012,China 2 Key Laboratory of Optical Astronomy,national astronomical observatories,{3.,beijing 100012,China national astronomical observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present spectroscopic observations for 11 confirmed globular clusters(GCs) of M3. with the OMR spectrograph on the 2.16 m telescope at the Xinglong site of national astronomical observatories,{3. academy of *** of our sample clusters are located in the halo of M3. and the most remote one is out to a projected radius of 78.75 kpc from the galactic *** all our sample clusters,we measured the Lick absorption-line indices and radial *** is noted that most GCs in our sample are distinct from the HI rotation curve of galaxy M3.,especially for B514,MCGC5,H12 and B517,suggesting that most of our sample clusters do not have a kinematic association with the star-forming young disk of the *** separately fitted the absorption line indices from the updated stellar population model of Thomas et *** two different tracks of Cassisi and Padova,by applying the χ2 minimization *** fitting results show that all our sample clusters are older than 10 Gyr,and metal-poor(2.3. ≤ [Fe/H] ≤ 0.91 dex).After merging the spectroscopic metallicity of our work with the previously published ones,we extended the cluster sample out to a projected radius of 117 kpc from the galaxy's *** found the metallicity gradient exists for all the confirmed clusters with a slope of 0.028 ± 0.001 dex kpc ***,the slope turns out to be 0.018 ± 0.001 dex kpc 1 for all the halo clusters,which is much *** we only consider the outer halo clusters with rp > 25 kpc,the slope becomes 0.010 ± 0.002 dex kpc 1 and if one cluster G001 is excluded from the outer halo sample,the slope is 0.004 ± 0.002 dex kpc ***,we conclude that the metallicity gradient for M3.'s outer halo clusters is not significant,which agrees well with previous findings.

关键词： galaxies individual(M3.) — galaxies star clusters — globular clusters general — star clusters general

Evidence of a two-component jet in the afterglow of GRB 070419A

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Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 265-266页

作者： ZHENG WeiKang1,2 & DENG JinSong1 1 national astronomical observatories,{3.,beijing 100012,China 2 Graduate University of chinese academy of Science,beijing 100049,China 1. national astronomical observatories Chinese Academy of Sciences Beijing 100012 China 2. Graduate University of chinese academy of Science Beijing 100049 China

A two-component jet model is proposed to explain the unusual afterglow of GRB *** the optical light curve,a wide "jet" with an opening angle of >3.-40 degrees is assumed to produce the late shallow decay,while the three early power-law segments must be caused by a narrow jet with an opening angle of-2-4 *** energy injections to both components are *** X-ray emission may come from either the wide jet or the narrow *** the latter is correct,the jets may run into an ISM environment and the temporal index of the late energy injection may be q-0.65.

关键词： gamma-rays:bursts gamma-rays:observations

Calibration of Vector Magnetogram with the Nonlinear Least-squares Fitting Technique

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chinese Journal of Astronomy and Astrophysics 2004年第4期4卷 365-376页

作者： jiang-TaoSu Hong-QiZhang nationalastronomicalobservatories ChineseAcademyofSciencesBeijing100012

To acquire Stokes profiles from observations of a simple sunspot with the Video Vector Magnetograph at Huairou Solar Observing Station (HSOS), we scanned the FeI λ53.4.19 A line over the wavelength interval from 150mA redward of the line center to 150mA blueward, in steps of 10mA. With the technique of analytic inversion of Stokes profiles via nonlinear least-squares, we present the calibration coefficients for the HSOS vector magnetic magnetogram. We obtained the theoretical calibration error with linear expressions derived from the Unno-Becker equation under weak-field approximation.

关键词： Sun: activity - Sun: magnetic fields - sunspots

k-Nearest Neighbors for automated classification of celestial objects

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Science China(Physics,Mechanics & Astronomy) 2008年第7期51卷 916-922页

作者： LI LiLi1,2,3. ZHANG YanXia1 & ZHAO YongHeng1 1 national astronomical observatories, {3., beijing 100012, China 2 Department of Physics, Hebei Normal University, Shijiazhuang 050016, China 3.Weishanlu Middle School, Tianjin 3.0222, China 1. national astronomical observatories Chinese Academy of Sciences Beijing 100012 China 2. Department of Physics Hebei Normal University Shijiazhuang 050016 China 3. Weishanlu Middle School Tianjin 300222 China

The nearest neighbors (NNs) classifiers, especially the k-Nearest Neighbors (kNNs) algorithm, are among the simplest and yet most efficient classification rules and widely used in practice. It is a nonparametric method of pattern recognition. In this paper, k-Nearest Neighbors, one of the most commonly used machine learning methods, work in automatic classification of multi-wavelength astronomical objects. Through the experiment, we conclude that the running speed of the kNN classier is rather fast and the classification accuracy is up to 97.73.. As a result, it is efficient and applicable to discriminate active objects from stars and normal galaxies with this method. The classifiers trained by the kNN method can be used to solve the automated classification problem faced by astronomy and the virtual observatory (VO).

关键词： k-Nearest Neighbors data analysis classification astronomical catalogues

Time-variation of the near 5-month period of sunspot numbers

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chinese Science Bulletin 2002年第23期47卷 1969-1973页

作者： HAN Yanben1 & HAN Yonggang1,21. national astronomical observatories, {3., beijing 100012, China 2. Department of Applied Mathematics, beijing Polytechnic University, beijing 100022, China national astronomical observatories Chinese Academy of Sciences Beijing China Department of Applied Mathematics Beijing Polytechnic University Beijing China

The variation of the near 5-month period of sunspot numbers is discussed on the basis of the wavelet transform of the daily sunspot number series in the 14th-22nd solar cycles. The result shows that the period exists in every cycle and its energy density (amplitude) is comparatively large in the peak section of the cycle. In the distinct cycle, the length and intensity of the period is different, which means that the period varies with time. The near 25-day period is also analyzed and it is found to be time-variable and even not very stable in the peak section of the cycle. The variations of the two periods show that the near 5-month period should not be simply regarded as the multiples of the near 25-day period.

关键词： solar activity sunspot time-variation wavelet.

Statistics of Galactic Supernova Remnants

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chinese Journal of Astronomy and Astrophysics 2005年第2期5卷 165-174页

作者： jian-WenXu Xi-ZhenZhang Jin-LinHan nationalastronomicalobservatories ChineseAcademyofSciencesBeijing100012

We collected the basic parameters of 23. supernova remnants (SNRs) in ourGalaxy, namely, distances (d) from the Sun, linear diameters (D), Galactic heights (Z), estimatedages (t), luminosities (L), surface brightness (Σ) and flux densities (S_1) at 1-GHz frequency andspectral indices (α). We tried to find possible correlations between these parameters. As expected,the linear diameters were found to increase with ages for the shell-type remnants, and also to havea tendency to increase with the Galactic heights. Both the surface brightness and luminosity ofSNRs at 1-GHz tend to decrease with the linear diameter and with age. No other relations between theparameters were found.

关键词： methods: statistical (ISM:) supernova remnants

Human CD56+CD3.+ dNK cells support fetal survival through controlling trophoblastic cell fate:immune mechanisms of recurrent early pregnancy loss

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national Science Review 2024年第6期11卷 129-145页

作者： Wentong Jia Liyang Ma Xin Yu Feiyang wang Qian Yang Xiaoye wang Mengjie Fan Yan Gu Ran Meng jian wang Yuxia Li Rong Li Xuan Shao Yan-ling wang State Key Laboratory of Stem cell and Reproductive Biology Key Laboratory of Organ Regeneration and ReconstructionInstitute of ZoologyChinese Academy of Sciences beijing Institute for Stem Cell and Regenerative Medicine University of the chinese academy of sciences NHC Key Lab of Reproduction Regulation Shanghai Engineering Research Center of Reproductive Health Drug and Devices Shanghai Institute for Biomedical and Pharmaceutical Technologies national Clinical Center for Obstetrics and Gynecology Peking University Third Hospital Department of Family Planning The Second Hospital of Tianjin Medical University Department of Prenatal Screening Haidian Maternal and Child Health Hospital

Decidual natural killer（dNK） cells are the most abundant immune cells at the maternal-fetal interface during early pregnancy in both mice and humans, and emerging single-cell transcriptomic studies have uncovered various human dNK subsets that are disrupted in patients experiencing recurrent early pregnancy loss（RPL） at early gestational stage, suggesting a connection between abnormal proportions or characteristics of dNK subsets and RPL pathogenesis. However, the functional mechanisms underlying this association remain unclear. Here, we established a mouse model by adoptively transferring human dNK cells into pregnant NOG（NOD/Shi-scid/IL-2Rγnull） mice, where human dNK cells predominantly homed into the uteri of recipients. Using this model, we observed a strong correlation between the properties of human dNK cells and pregnancy outcome. The transfer of dNK cells from RPL patients（dNK-RPL）remarkably worsened early pregnancy loss and impaired placental trophoblast cell differentiation in the recipients. These adverse effects were effectively reversed by transferring CD56+CD3.+dNK *** studies revealed that CD56+CD3.+dNK subset facilitates early differentiation of mouse trophoblast stem cells（m TSCs） towards both invasive and syncytial pathways through secreting macrophage colony-stimulating factor（M-CSF）. Administration of recombinant M-CSF to NOG mice transferred with dNK-RPL efficiently rescued the exacerbated pregnancy outcomes and fetal/placental development. Collectively, this study established a novel humanized mouse model featuring functional human dNK cells homing into the uteri of recipients and uncovered the pivotal role of M-CSF in fetal-supporting function of CD56+CD3.+dNK cells during early pregnancy, highlighting that M-CSF may be a previously unappreciated therapeutic target for intervening RPL.

关键词： recurrent pregnancy loss CD56+CD3.+ dNK subset NOG mice adoptive transfer placental trophoblast cell fate M-CSF