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Avoided crossings between non-radial modes in low mass RGB stars

Research in astronomy and Astrophysics 2012年第12期12卷 1655-1665页

作者： Jun-Jun Guo1,2.3,Yan Li1,2.and Xiang-Jun Lai1,2.1 national astronomical Observatories/Yunnan Observatory,{2., Kunming 650011,china 2.key laboratory for the Structure and Evolution of Celestial Objects,{2.,Kunming 650011,china 3 Graduate University of {2.,beijing 100049,china national astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China key laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China Graduate University of chinese academy of sciences Beijing 100049 China

Non-radial p modes and g modes appear simultaneously in red giant stars. Their frequencies have different variation rates,causing their frequencies to become close during stellar evolution so that avoided crossings *** separation between regions where acoustic waves and gravity waves propagate for l=1,2.and 3 is different,which results in the coupling efficiency also being *** present the results of numerical computations of the models we *** find that the two kinds of modes for l=2.and 3 need to be closer in frequency in order for a complete exchange to occur,compared to the case for modes with l=*** scaled oscillation frequencies also present better regularity with evolution than modes with l=1. In order to study the effect of the avoided crossings in detail,we set the mode which has the smallest mode inertia to be the p *** plot the two kinds of modes for l =1,2.and 3 in frequency and periodéchelle diagrams and find modes of l=2.and 3 fit the two relations better;they are more equally spaced in frequency and period than modes with l=*** careful observation of the two kinds oféchelle diagrams for l=2.and 3,we still find that some p modes shift a little from being equally spaced in frequency and some g modes,which are close to those p modes in period,shift a little from being equally spaced in ***,we study the relation between the deviation from period being equally spaced and the mode inertia of g modes for different *** g modes of l=1 with a period closer to the p mode have less inertia and the deviation is bigger in the periodéchelle *** deviation is also obvious. However g modes of l=2.and 3 shift a little or have almost no deviation from being equally spaced in period,even though some of them may have strong coupling and close mode inertia like in the p ***,we suggest a possible method for measuring period spacing of g modes precisely using mixed g modes with l=2.and 3 that have fewer observed mixed g m

关键词： stars:oscillations-stars:red giants

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Discovery of an optical Jet in the Rosette Nebula: Rosette HH2

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chinese Journal of astronomy and Astrophysics 2003年第6期3卷 495-498页

作者： Jin-Zeng Linational astronomical Observatories, {2., beijing 100012 national astronomical Observatories Chinese Academy of Sciences Beijing 100012

We report on the discovery of an optical jet - Rosette HH2.- in the RosetteNebula. The jet system bears unique features for residing at the center of a giant HII region, andits energy source is visible with apparently very low extinction along the line of sight. Unlikemost other Herbig-Haro jets, this jet indicates a high-excitation origin, and its extended portionshows a seemingly intact structure, instead of normally a shocked working surface, which isattributed to photoablation.

关键词： stars: formation stars: pre-main sequence herbig-haro objects ISM: jetsand outflows

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Analysis on the positioning precision of CAPS

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Science china(Physics,Mechanics & astronomy) 2009年第3期52卷 328-332页

作者： JI YuanFa1,2.& SUN XiYan1,2.1 national astronomical Observatories, {2., beijing 100012, china 2.Applied Science and Technology College, Guilin University of Electronic Technology, Guilin 541004, china 1. national astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 2. Applied Science and Technology College Guilin University of Electronic Technology Guilin 541004 China

As a newly developed satellite positioning system, the chinese Area Positioning System (CAPS) is a typical direct sequence spread spectrum ranging system like GPS. The positioning precision of such navigation signals depends on many factors, including the pseudo-code rate, the signal to noise ratio, the processing methods for tracking loops and so on. This paper describes the CAPS link budget, the solution approach for CAPS positioning, focusing on the autocorrelation function feature of C/A code signals. The CAPS signal measurement precision is studied by the software approach together with theoretical analysis of the range resolution. Because the conventional Delay Lock Loop (DLL) is vul- nerable to the impact of noise, a narrow correlator and multiple correlators as well as the corresponding discrimination methods of phases are proposed, which improves the robustness of DLL and the code-phase resolution of the measurement. The results show that the improvement of the DLL structure and the discrimination method are the most important way to improve the ranging resolution. Theoretical analysis and experimental results show that a CAPS receiver could reach a 2.-m positioning precision by using three satellites with a supported height from an altimeter.

关键词： satellite navigation receiver narrow correlation tracking loop

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IRAS 01005+7910:a High Galactic Latitude Post-AGB Star

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chinese Journal of astronomy and Astrophysics 2002年第3期2卷 193-196页

作者： Jing-Yao Hunational astronomical Observatories, {2., beijing 100012 national astronomical Observatories Chinese Academy of Sciences Beijing 100012

IRAS 01005+7910 is a cold IRAS source. We present its optical identification, photometric and spectroscopic observation results. Its optical counterpart is classified as a B2.e star with V magnitude 10.85. Its Hα line shows the P Cygni profile. According to its location in the Galaxy (b = 16.6), we consider it to be a post-AGB star or a proto-planetary nebula.

关键词： stars: post-AGB - infrared: stars - stars: evolution

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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,{2.,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 >30-40 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

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Pulsars in FIRST Observations

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chinese Journal of astronomy and Astrophysics 2002年第2期2卷 146-150页

作者： Xiang-Hua Li and Jin-Lin Han national astronomical Observatories, {2., beijing 100012 national astronomical Observatories Chinese Academy of Sciences Beijing 100012

We identify 16 pulsars from the Survey of Faint Images of the Radio Sky at Twenty-cm (FIRST) at 1.4 GHz. Their positions and total flux densities are extracted from the FIRST catalog. By comparing the source positions with those in the PSR catalog, we obtain better determined positions of PSR J102.+1001, J1518+4904, J1652.2.51, and proper motion upper limits of PSR J0751+1807, J1012.5307, and J1640+2.2.. The proper motions of the other ten pulsars are consistent with the catalog values.

关键词： pulsar: general -stars: neutron

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Wet-chemical synthesis and characteristics of Au nanoshell

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Science china Chemistry 2005年第5期48卷 431-435页

作者： LIU Zhongxin1,2. SONG Hongwei1, YU Lixin1,2. YANG Linmei1,2.& PAN Guohui1,2.1. key laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, {2., Changchun 130033, china 2. Graduate School of the {2., beijing 100039, china 1. key laboratory of Excited State Physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences 130033 Changchun China 2. Graduate School of the chinese academy of sciences 100039 Beijing China

Gold nanoshells were prepared by an easy wet-chemical method, with Ag nanoparticles used as the templates. Transmission electron microscopy (TEM) indicated that the shells were sphere in shape, the size was homogenous, being about 2. nm, and no hard ag-glomerates were observed. The plasma resonance absorption of gold was tuned from visible to near-infrared (NIR) with the increased volume of HAuCl4. The temperature grads (?T) of the gold nanoshell hydrosol under the exposure of an 808-nm optical fiber laser with different power den-sities were measured. The highest ?T was 30℃ (5 W/cm2. irradiation area was 2.cm2.. This kind of gold nanoshell hydrosol is a promising material to be used in biomedicine such as photo-thermal cancer therapy, and its special photothermal convert property will photothermally trigger drug release.

关键词： wet-chemical synthesis, Au, nanoshell, NIR absorption, photothermal conversion.

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Metallicity calibration for solar type stars based on red spectra

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Research in astronomy and Astrophysics 2011年第5期11卷 563-576页

作者： Jing-KunZhao GangZhao Yu-QinChen A-LiLuo keylaboratoryof{2.astronomy NationalAstronomicalObservatoriesChineseAcademyofSciencesBeijing100012China

Based on a high resolution and high signal-to-noise ratio （S/N） spectral analysis of 90 solar-type stars, we have established several new metaUicity calibrations in the Tefr range [5600, 6500] K based on red spectra with the wavelength range of 560-880 nm. The new metallicity calibrations are applied to determine the metallicity of solar analogs selected from Sloan Digital Sky Survey （SDSS） spectra. There is a good consistent result with the adopted value presented in SDSS-DR7 and a small scatter of 0.2. dex for stars with S/N 〉 50 being obtained. This study provides a new reliable way to derive the metallicity for solar-like stars with low resolution spectra. In particular, our calibrations are useful for finding metal-rich stars, which are missing in the SEGUE Stellar Parameter Pipeline.

关键词： techniques: radial velocities - stars: temperatures - stars: abundances

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A comparative analysis on two solar proton events

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chinese Science Bulletin 2007年第1期52卷 47-51页

作者： LE GuiMing1,2.3,4, HAN YanBen2.& ZHANG YiJun3 1 key laboratory of Radiometric Calibration and Validation for Environmental Satellites, {2. Meteorological Administration, beijing 100081, {2. 2.national astronomical Observatories, chinese academy of sciences, beijing 100012, {2. 3 chinese {12. of Meteorological sciences, {2. Meteorological Administration, beijing 100081, {2. 4 national Center for Space Weather, {2. Meteorological Administration, beijing 100081, {2. key laboratory of Radiometric Calibration and Validation for EnvironmentalSatellites China Meteorological Administration Beijing 100081 China

This paper presents a comparative analysis on the two Solar Proton Events (SPE), which occurred on 14 July 2.00 (Bastille Day) and 2. October 2.03 (2.OCT03) respectively. It is found that although the peak flux of the latter seemed to be greater than that of the former based on geostationary observations, the maximum intensities of the energetic protons (>10 MeV and 30 MeV) during the Bastille Day event were all higher than those of the 2.OCT03 event according to the interplanetary observations. Further analysis indicated that the quantity of the seed particles, which could be accelerated to the energies exceeding 10 and 30 MeV by the Coronal Mass Ejection (CME)-driven shock on 14 July 2.00, was far larger than that of the 2.OCT03 event. In the Bastille Day case, when the CME approached to the height around 14 R⊙, the CME-driven shock would reach its maximum capacity in accelerating the solar en- ergetic protons (>100 MeV). In contrast, on 2. October 2.03, when CME approached to the height about 58R⊙, the CME-driven shock reached its highest potential in accelerating the solar energetic protons of the same category. At this moment, the peak flux (>100 MeV) was about 155 pfu, which was much lower than 355 pfu measured on 14 July 2.00. This demonstrated that in the Bastille Day event, the quantity of the seed particles, which could be accelerated to the energy beyond 100 MeV, was significantly larger than its counterpart in the 2.OCT03 case. Therefore, the peak flux of an SPE event depends not only on the interplanetary intensity of the solar energetic particles, but also on the velocity of the associated CME-driven shock, and the quantity of the seed particles as well as on the interplanetary magnetic en- vironment. This paper also reveals that the magnetic sheath associated with ICME on 2. October 2.03 captured a large number of solar energetic protons, including those having energy greater than 100 MeV.

关键词：太阳质子 CME 太阳耀斑太阳系

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Focal plane wave-front sensing algorithm for high-contrast imaging

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Science china(Physics,Mechanics & astronomy) 2009年第8期52卷 1284-1288页

作者： DOU JiangPei1,2.3,REN DeQing1,2.4,ZHU YongTian1,2.& ZHANG Xi1,2.3 1 national astronomical Observatories/Nanjing Institute of astronomical Optics & Technology,chinese academy of sciences,Nanjing 2.0042.china 2.key laboratory of astronomical Optics & Technology,Nanjing Institute of astronomical Optics & Technology,chinese academy of sciences,Nanjing 2.0042.china 3 Graduate University of chinese academy of sciences,{12. 100049,china 4 Physics & astronomy Department,California State University Northridge,18111 Nordhoff Street,Northridge,California 91330-82.8,USA national astronomical Observatories/Nanjing Institute of astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China key laboratory of {2. Optics & Technology Nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Graduate University of chinese academy of sciences Beijing 100049 China Physics & astronomy Department California State University Northridge 18111 Nordhoff Street Northridge California 91330-8268 USA

High-contrast imaging provided by a coronagraph is critical for the direction imaging of the Earth-like planet orbiting its bright parent star.A major limitation for such direct imaging is the speckle noise that is induced from the wave-front error of an optical *** derive an algorithm for the wave-front measurement directly from 3 focal plane *** 3 images are achieved through a deformable mirror to provide specific phases for the optics *** introduce an extra amplitude modulation on one deformable mirror configuration to create an uncorrelated wave-front,which is a critical procedure for wave-front *** simulation shows that the reconstructed wave-front is consistent with the original wave-front theoretically,which indicates that such an algorithm is a promising technique for the wave-front measurement for the high-contrast imaging.

关键词： high-contrast imaging multi-image algorithm speckle nulling technique wave-front sensing

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