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Equivalent Widths of 15 Extrasolar-Planet Host Stars

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chinese Journal of Astronomy and Astrophysics 2002年第4期2卷 377-390页

作者： Gang Zhao, Yu-Qin Chen and Hong-Mei Qiunational astronomical observatories, chinese academy of sciences, beijing 100012 national astronomical observatories CAS NAOC Beijing 100012 China

We present the equivalent widths of 15 extrasolar-planet host stars. These data were based on the high-resolution, high signal-to-noise ratio spectra obtained with the 2.16m telescope at Xinglong station. The error in the Xinglong equivalent width is estimated by a comparison of these data with those given in previous studies of common stars.

关键词： stars: planetary systems - stars: late-type

Evolution of the Level of Sunspot Activity in Solar Cycles I. Evolution in the Descending Phase

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chinese Journal of Astronomy and Astrophysics 2006年第3期6卷 354-362页

作者： Jia-Long Wang national astronomical observatories Chinese Academy of Sciences Beijing 100012

Taking the 13-point smoothed monthly sunspot number,Ri, and the deviation of the 13 associated monthly sunspot numbers from the smoothed one, Di, as a number-pair describing the global level of sunspot activity, the evolution of the level is statistically studied for the period from the month which is just 48 months before the minimum to the minimum in the descending phase, using the observed data of Solar Cycles 10 to 22. Our results show （1） for 46 months （94%） of the studied 49 months it is found that for a given month, the distribution of the 13 pairs which come from the 13 solar cycles on a log Ri - Di plane may be fitted by a straight line with a correlation coefficient larger than the critical one at confidence level a = 5%, and for 36 months （73%） the fitting is even better, for a = 1%; （2） time variations of these two parameters and their correlations in the studied period can be described respectively by functions of time, whose main trends may be expressed by a linear or simple curvilinear function; （3） the evolutionary path of the level of sunspot activity may be represented by a logarithmic function as log/~ = 0.704 lnDi - 0.291.

关键词： Sun - sunspots - active level evolution

Expectation for the X-ray Galactic Halo

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chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 112-116页

作者： Zhi-Ying Huo national astronomical observatories, chinese academy of sciences, beijing 100012 Department of Physics, Tianjin Normal University, Tianjin 300073 national astronomical observatories Chinese Academy of Sciences Beijing 100012 Department of Physics Tianjin Normal University Tianjin 300073

We present an estimate of the strength and spectrum of the X-ray background from the warm gas associated with the Galactic halo. This investigation is motivated primarily by the recent detection of a spatially variable soft X-ray component towards the north Galactic polar cap by Kuntz et al. (2001), suggesting that the warm gas heated by gravitational shocks of the Galactic halo may produce a significant contribution to the soft X-ray sky. Another purpose of the study is to refine the recent theoretical prediction of the X-ray spectrum from the Galactic halo by Xue (2001) who adopted an ideal and simple isothermal model for the gas and dark matter distributions of the Galactic halo. We use the universal density profile for the dark matter distributions of the Galactic halo to evaluate the X- ray properties of the warm gas either in hydrostatic equilibrium with, or tracing the underlying gravitational potential of the Galaxy. It has been shown that our prediction is consistent with the measured soft X-ray component towards the north Galactic polar cap if the gas fraction is taken to be^0.005.

关键词： cosmology: diffuse radiation -Galaxy: formation - X-rays: galaxies

2023 Guideline for the management of hypertension in the elderly population in china

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Journal of Geriatric Cardiology 2024年第6期21卷 589-630页

作者： Hypertension Branch of chinese Geriatrics Society,beijing Hypertension Association,national Clinical Research Center of the Geriatric Diseases Qi HUA Li FAN Zeng-Wu WANG Jing LI 不详 Xuanwu Hospital Capital Medical UniversityBeijingChina chinese PLA General Hospital BeijingChina Fuwai Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Preamble Hypertension is one of the most common chronic diseases and the primary risk factor for stroke,myocardial infarction and even cardiovascular *** than half of the elderly population has high blood *** people are a unique group,and strategies for the prevention,diagnosis,evaluation,and treatment of hypertension in elderly individuals differ significantly from those in the general population.

关键词： hypertension prevention diagnosis

Is the Variable X-ray Source in M82 due to Gravitational Lensing?

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chinese Journal of Astronomy and Astrophysics 2001年第4期1卷 287-290页

作者： Da-Ming Chen (national astronomical observatories, chinese academy of sciences, beijing 100012)E-mail:dmchen66@*** national astronomical observatories Chinese Academy of Sciences Beijing 100012

We explore the possibility of attributing the recent discovery of the variable hard X-ray source CXO M82 J095550.2+694047 in M82 to the gravitational magnification by an intervening stellar object along the line of sight acting as a microlens. The duration of the event (> 84 days) allows us to set robust constraints on the mass and location of the microlensing object when combined with the dynamical properties of the Galactic halo, M82 and typical globular clusters. Except for the extremely low probability, the microlensing magnification by MACHO in either the Galactic halo or M82 halo is able to explain the X-ray variability of CXO M82 J095550.2+694047. It is hoped that the lensing hypothesis can be tested soon by measurement of the light curve.

关键词： X-rays: stars - Galaxies: individual: M82 - gravitational lensing

Magnetic Helicity Injection in Solar Active Regions

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chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 96-112页

作者： Hong-Qi Zhang national astronomical observatories Chinese Academy of Sciences Beijing 100012

We present the evolution of magnetic field and its relationship with magnetic （current） helicity in solar active regions from a series of photospheric vector magnetograms obtained by Huairou Solar Observing Station, longitudinal magnetograms by MDI of SOHO and white light images of TRACE. The photospheric current helicity density is a quantity reflecting the local twisted magnetic field and is related to the remaining magnetic helicity in the photosphere, even if the mean current helicity density brings the general chiral property in a layer of solar active regions. As new magnetic flux emerges in active regions, changes of photospheric cur- rent helicity density with the injection of magnetic helicity into the corona from the subatmosphere can be detected, including changes in sign caused by the injection of magnetic helicity of opposite sign. Because the injection rate of magnetic helicity and photospheric current helicity density have different means in the solar atmosphere, the injected magnetic helicity is probably not proportional to the current helicity density remaining in the photosphere. The evidence is that rotation of sunspots does not synchronize exactly with the twist of photospheric transverse magnetic field in some active regions （such as, delta active regions）. They represent different aspects of magnetic chirality. A combined analysis of the observational magnetic helicity parameters actually provides a relative complete picture of magnetic helicity and its transfer in the solar atmosphere.

关键词： Sun: activity Sun: magnetic fields

Relativist ic Corrections to the Thermal Sunyaev-Zel'dovich Power Spectrum

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chinese Journal of Astronomy and Astrophysics 2003年第5期3卷 410-414页

作者： Hai-Ning Linational astronomical observatories, chinese academy of sciences, beijing 100012 lhnDepartment of Astronomy, beijing Normal University, beijing 100875 national astronomical observatories CAS NAOC Beijing 100012 China Department of Astronomy Beijing Normal University Beijing 100875

We present a quantitative estimate of the relativistic corrections to thethermal SZ power spectrum produced by the energetic electrons in massive clusters. The correctionsare well within 10% for current experiments with working frequencies below ν 350 GHz. Moreover, the corrections appear to be slightlysmaller at higher l or smaller angular scales. We conclude that there is no need to include therelativistic corrections in the theoretical study of the SZ power spectrum especially at lowfrequencies unless the SZ power spectrum is used for precision cosmology.

关键词： cosmic microwave background cosmology: theory galaxies: clusters: general

Comparisons of Infrared Colors and Emission-line Intensities between Two types of Seyfert 2 Galaxies

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chinese Journal of Astronomy and Astrophysics 2002年第5期2卷 408-418页

作者： Lin-Peng Cheng, Yong-Heng Zhao and Jian-Yan Weinational astronomical observatories, chinese academy of sciences, beijing 100012 national astronomical observatories CAS NAOC Beijing China

We study the relation between the infrared colors, [OIII] emission lines, gaseous absorbing column density (NH),and the detectability of the polarized (hidden) broad-line region (HBLR) in a large sample of 75 Seyfert 2 galaxies (Sy2s). From the indicators of star-formation activity, f60/f100 and LFIR/LB, we find some evidence that the Sy2s without HBLR show higher star-formation activities than those with HBLR, in agreement with previous prediction. Also, we confirm that the HBLR Sy2s tend to have a larger luminosity ratio of the core to the host galaxy, suggesting that the HBLR Sy2s display more powerful AGN activity. However, the level of obscuration found in previous papers is nearly indistinguishable between the two types of Sy2s. The results support the statement that the non-HBLR Sy2s, with a weaker core component and a stronger star-formation activity component, are intrinsically different from the HBLR Sy2s, which are Sy1 systems with a hidden powerful AGN core and a low star-formation activity. The indications are that the non-HBLR Sy2s might be at an earlier evolutionary phase than the HBLR Sy2s.

关键词： galaxies: active - galaxies: Seyfert - polarization - star formation

The Variability of Hardness Ratio 1 observed by ROSAT:Narrow-Line Seyfert 1 Galaxies versus Broad-Line Seyfert 1 Galaxies

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chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 207-215页

作者： Lin-Peng Cheng , Jian-Yan Wei and Yong-Heng Zhaonational astronomical observatories, chinese academy of sciences, beijing 100012 national astronomical observatories Chinese Academy of Sciences Beijing 100012

We examined the correlation between the ROSAT Hardness Ratio 1 and Count Rates eight Narrow-line Seyfert 1 Galaxies (NLSls) and 14 Broad-line Seyfertl Galaxies (BLSls). We found that six of the NLSls show a positive HR1-CTs correlation, and seven of the BLSls, a negative correlation. The other two NLSls and seven BLSls do not show any clear HR1-CTs correlation. Thus, the spectral behavior is statistically different for the NLSls and BLSls. The different behaviors can possibly be interpreted in terms of a stable 'soft excess' that is strong in NLSls and weak in BLSls, plus a power law component, common to both, which softens with increasing flux.

关键词： galaxies: Seyfert - galaxies: active - X-ray: galaxies