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Petrology and mineral chemistry of new ureilites found in Grove Mountains, Antarctica

Progress in Natural Science:Materials International 2008年第4期18卷 431-439页

作者： Bingkui Miaoa,b,, Yangting Linb, Guiqin Wangc, Daode Wangc, Ziyuan Ouyangd a key laboratory of Geological Engineering Center of Guangxi Province, Guilin University of Technology, Guilin 541004, China b State key laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, chinese academy of sciences, beijing 100029, China c key laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, Chinad national astronomical observatories, chinese academy of sciences, beijing 100012. China key laboratory of Geological Engineering Center of Guangxi Province Guilin University of Technology Guilin 541004 China State key laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China key laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

Petrography and mineral chemistry of two new ureilites, GRV 02.512.and 02.931, from the Grove Mountains, Antarctica, are reported in this paper. GRV 02.512.exhibits a typical ureilite texture, and consists of 48.3% olivine, 9.4% pigeonite and 38.1% carbo- naceous interstitial material and/or reduction product. GRV 02.931 has a cataclastic porphyritic texture, and consists of 19.1% olivine and 14.1% pigeonite embedded in 66.3% carbonaceous interstitial material and/or reduction product. The coarse-grained olivine and pigeonite in both meteorites have homogeneous cores, and they are FeO-rich within the range of the ferroan subgroup (subgroup I) of olivine-pigeonite ureilites. All olivine grains of the meteorites show reduction zones along boundaries and cracks. Abundant diamond coexists with graphite as graphite-rich patches and veins in the carbonaceous interstitial material. Petrogenesis of both meteorites and the origin of diamond are discussed.

关键词： Meteorite Achondrite Ureilite Diamond Antarctica

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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 nationalastronomical{2. 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 λ532..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

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Anisotropic Beam Model for the Spectral Observations of Radio Burst Fine Structures on 1998 April 15

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chinese Journal of Astronomy and Astrophysics 2001年第5期1卷 475-482页

作者： V.G. LedenevE-mail:yyh@*** , Yi-Hua Yan, and Qi-Jun Fu (national astronomical {2., chinese academy of sciences, beijing 100012. (Institute of solar-Terrestrial Physics, Siberian Division of Russian academy of sciences 664033, Irkutsk, P. 0 Institute of solar-Terrestrial Physics Siberian Division of Russian Academy of Sciences 664033 Irkutsk P. O. Box 4026 Russia

A fine structure consisting of three almost equidistant frequency bands was observed in the high frequency part of a solar burst on 1998 April 15 by the spectrometer of beijing {2. Observatory in the range 2.6-3.8 GHz. A model for this event based on beam-anisotropic instability in the solar corona is presented. Longitudinal plasma waves are excited at cyclotron resonance and then transformed into radio emission at their second harmonic. The model is in accordance with the observations if we suppose a magnetic field strength in the region of emission generation of about 2.0 G.

关键词： Sun: radio radiation Sun: activity - Sun: corona

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Possible triggering of solar activity to big earthquakes (Ms ≥ 8) in faults with near west-east strike in China

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Science China(Physics,Mechanics & Astronomy) 2004年第2期47卷 173-181页

作者： HAN Yanben1, GUO Zengjian1,2. WU Jinbing1,2.& MA Lihua1 1. national astronomical {2., chinese academy of sciences, beijing 100012. China 2. Earthquake Research Institute of Lanzhou, CSB, Lanzhou 73000, China Correspondence should be addressed to Han Yanben (email: hyb@***) 1. national astronomical {2. Chinese Academy of Sciences 100012 Beijing China 2. Earthquake Research Institute of Lanzhou CSB 73000 Lanzhou China

This paper studies the relationship between solar activity and big earthquakes (Ms≥8) that occurred in China and western Mongolia. It is discovered that the occurrence dates of most of the big earthquakes in and near faults with west-east strike are close to the maximum years of sunspot numbers, whereas dates of some big earthquakes which are not in such faults are not close to the maximum years. We consider that it is possibly because of the appearance of many magnetic storms in the maximum years of solar activity. The magnetic storms result in anomalies of geomagnetic field and then produce eddy current in the faults gestating earthquake with near west-east strike. Perhaps the gestated big earthquakes occur easily since the eddy current heats the rocks in the faults and therefore decreases the shear resistant intensity and the static friction limit of the rocks .

关键词： earthquake, solar activity, magnetic storm, eddy current.

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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 {2., chinese academy of sciences, beijing 100012. China 2.Applied Science and Technology College, Guilin University of Electronic Technology, Guilin 541004, China 1. national astronomical {2. 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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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 keylaboratoryofOpticalAstronomy 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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An Electron Density Model above the Sunspot from a Mapping of NOAA 72.0 at 17 GHz

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chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 287-292页

作者： Xing－FengYu Jin－XingYao nationalastronomical{2. ChineseAcademyofSciencesBeijing100012 PurpleMountainObservatory ChineseAcademyofSciencesNanjing210008

The brightness temperature distribution of microwave emission in a solar active region generally shows a ring structure, with a dip at the centre. However, no dip was found in the Nobeyama Radioheliograph left handed circular polarization (LCP) image on 1992.August 18; instead, there was a peak. This is a completely LCP source with zero right-handed circular polarization (RCP). We examine this structure in terms of the joint effect of gyroresonance and bremsstrahlung mechanism with a raised electron density above the central part of the sunspot, and the commonly assumed temperature and vertical dipole magnetic field models. The raised electron density is found to be 1.4 × 1011 cm-3 at the chromosphere base.

关键词： Sun: activity - sunspots - Sun: radio radiation - Sun: chromosphere

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solar release time of solar energetic particles and associated acceleration source in corona

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chinese Science Bulletin 2008年第2期53卷 161-168页

作者： LE GuiMing1,2.3,4, TANG YuHua1 & HAN YanBen4 1 Department of Astronomy, Nanjing University, Nanjing 2.0093, China 2.key laboratory of Radiometric Calibration and Validation for Environmental Satellites, China Meteorological Administration, {2. 100081, China 3 national Center for Space Weather, China Meteorological Administration, {2. 100081, China 4 national astronomical observatories, chinese academy of sciences, {2. {12. China Department of Astronomy Nanjing University Nanjing China key laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing China national Center for Space Weather China Meteorological Administration Beijing China national astronomical {2. Chinese Academy of Sciences Beijing China

solar energetic particles (SEPs) are accelerated in corona at an early phase of solar energetic particle events (SEPE). The acceleration mechanism of SEPs in corona can only be inferred from an analysis of multi-band observational data, as the observation of SEPs is usually made around 1AU. In this context, people have investigated spectrums, charge state, solar release time (SRT), and multi-band data of SEPEs, in an attempt to judge the acceleration mechanism of SEPs. The SRT computation of SEPs is an important and commonly used approach to study the acceleration mechanism of SEPs in corona. This paper reviews some important findings concerning the SRT computation of SEPs, and analyzes different merits of each approach for such calculation, based on a range of SEPE case studies. This paper also analyzes and discusses both possible and actual acceleration mechanisms of a number of SEPEs, by calculating the SRT of the SEPEs. Finally, the paper summarizes the possible problems in studying an acceleration mechanism of SEPEs inferred from the SRT of SEP.

关键词：阳光释放时间加速度电晕太阳耀斑

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Can Asymmetry of solar activity be Extended into Extended Cycle?

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chinese Journal of Astronomy and Astrophysics 2002年第1期2卷 66-70页

作者： Ke－JunLi Jing－XiuWang 等 YunnanObservatory ChineseAcademyofSciencesKunming650011 nationalastronomical{2. ChineseAcademyofSciencesBeijing100012

With the use of the Royal Greenwich Observatory data set of sunspot groups, an attempt is made to examine the north-south asymmetry of solar activity in the 'extended' solar cycles. It is inferred that the asymmetry e... 详细信息

关键词： Sun: sunspot - Sun: active cycle - Sun: activity

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Spectral analysis of two solar twins and the colors of the Sun

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 579-585页

作者： ZHAO ZhengShi1,2. CHEN YuQin1, ZHAO JingKun1 & ZHAO Gang1 1 national astronomical {2., chinese academy of sciences, beijing 100012. China 2.Graduate University of chinese academy of sciences, beijing 100049, China 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

High resolution (R^40,000) and high signal-to-noise ratio (>150) spectra of two solar twins, HD1462.3 and HD195034, are obtained with the Coude Echelle Spectrograph at the 2.16 m telescope of the national astronomical observatories of chinese academy of sciences (Xinglong, China). Based on the detailed spectrum match, comparisons of chemical composition and chromospheric {2., HD1462.3 and HD195034 are confirmed that they are similar to the Sun except for lithium abundance, which is higher than the solar value. Moreover, among nine solar twin candidates (including HD1462.3 and HD195034) found in the previous works, we have picked out six good solar twin candidates based on newly-derived homogenous parameters, and collected their colors in the Johnson/Cousins, Tycho, 2.ASS and Strmgren system from the literature. The average color are (B-V)⊙=0.644 mag, (V-Ic)⊙=0.707 mag, (BT-VT)⊙=0.72. mag, (J-H)⊙=0.2.8 mag, (H-K)⊙=0.066 mag, (v-y)⊙=1.02. mag, (v-b)⊙=0.619 mag, (u-v)⊙=0.954 mag and (b-y)⊙=0.409 mag, which represent the solar colors with higher precision than previous works.

关键词： Sun-colors Star-atmospheres abundances fundamental parameters

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