A Probable Short Decimetric Type Ⅰ-like Noise Storm: Associated with Type Ⅲ Bursts?

A rare Type I-like noise storm was observed with the solar radio spectrometers (1.0-2.0 GHz and 2.60-3.8 GHz) at National Astronomical Observatories of China (NAOC) on September 23, 1998. We concentrate on checking the Type I-like noise storm occurred in the decay phase of a Type Ⅳ radio burst. This noise storm consists of many Type I bursts and isolated Type Ⅲ or Type Ⅲ pair bursts. It has a bandwidth of ≤0.5 GHz. The duration of each Type I burst is of the order of 100-300 ms. The total duration is greater than 11 minutes. The circular polarization     

太阳物理学中的分形和混沌

对非线性科学的两个重要分支；分形和混沌在太阳物理学中的应用情况作了综述信要内容包括；太阳活动混沌性的揭示；对太阳活动混沌性的可能解释－太阳非线性发电机理论；一些太阳现象的分形描述；耀斑的自组织临界行为研究，最后给出了作者对这一领域工作前景的展望。     

On the DB gap of white dwarf evolution:effects of hydrogen mass fraction and convective overshooting

We investigate the spectral evolution of white dwarfs by considering the effects of hydrogen mass in the atmosphere and convective overshooting above the convection zone.Our numerical results show that white dwarfs with MH～10-16M⊙ show the DA spectral type between 46000■Teff■26000K and the DO or DB spectral type may appear on either side of this temperature range.White dwarfs with10-15M⊙ appear as DA stars until they cool to Teff～31000K;from then on they will evolve into DB white dwarfs as a result of conve...     

Magnetic activity of the spotted dwarf AP149 in the α Persei open cluster

The simultaneous photometric and spectroscopic observations of the spotted G dwarf AP149 in the young open cluster α Persei are analyzed here.We reconstruct the observed light curves with a two-starspot model by means of a light curve modeling technique,and find that the active regions shift oppositely along longitude on a time scale of one day.Combining with the observational data obtained by other groups,we discuss the evolution of spotted regions in the photosphere,and find that its starspots evolve not ...     

WD+RG systems as the progenitors of type Ia supernovae

Type Ia supernovae(SNe Ia)play an important role in the study of cosmic evolution,especially in cosmology.There are several progenitor models for SNe Ia proposed in the past years.By considering the effect of accretion disk instability on the evolution of white dwarf(WD)binaries,we performed detailed binary evolution calculations for the WD+red-giant(RG)channel of SNe Ia,in which a carbon-oxygen WD accretes material from a RG star to increase its mass to the Chandrasekhar mass limit.According to these calcu...     

Characteristics of infrared point sources associated with OH masers

We collect 3249 OH maser sources from the literature published up to April 2007, and compile a new catalog of OH masers. We look for the exciting sources of these masers and their infrared properties from IRAS and MSX data, and make a statistical study. MSX sources associated with stellar 1612 MHz OH masers are located mainly above the blackbody line; this is caused by the dust absorption of stellar envelopes, especially in the MSX A band. The mid-IR sources associated with stellar OH masers are concentrate...     

多层湍流大气相位屏的数值模拟

高分辨图像重建技术可以有效消除湍流大气的影响,重建目标的接近望远镜衍射极限的图像。但是当目标的视场角比较大时,大气—望远镜综合系统不再是线性空不变的,给图像重建带来新的困难,它是大气性质中的一个重要特性,对大气相位屏的模拟应该满足这一特性。提出了一种可以模拟等晕区效应的多层大气相位屏的数值模拟方法,这种方法可以应用于等晕区对高分辨统计重建方法的影响的研究中。利用该数值模拟方法模拟了5″和8″的双星的斑点图,用斑点干涉术对模拟的双星进行了重建,并与实测的双星的斑点干涉术重建结果进行了比较。比较结果表明该数值模拟方法所产生的等晕区效应与实际的等晕区效应相似。     

大气对532nm激光影响在漫反射激光测距中的应用

激光光束在大气中的传输是与大气特征有关的,如大气湍流、大气散射与吸收,而且激光测距的回波除了与距离有关外,其回波数及精度也与大气特征相关。漫反射激光测距的目标是低轨空间碎片,在一定反射截面的条件下,应用一定功率的激光进行地面靶板漫反射测距试验,以确定多少功率的激光器可实现空间碎片的漫反射测距,这时地面靶的距离选取应该具有代表性,它代表了在一定斜程下穿过整个大气层的效应。通过对大气湍流和大气衰减对激光传输的影响进行分析,理论上计算出在低轨目标为400km时,漫反射激光测距试验地面靶的水平距离该取多远时才能代表在一定斜程下穿过400km大气层的效应,从而为漫反射激光测距试验地面靶距离的选取提供参考依据。     

利用中国地壳运动观测网络研究中国大陆相对于ITRF97板块模型形变

在建立全球ITRF97板块运动模型的基础上,利用"中国地壳运动观测网络"79个GPS基本站的数据,建立我国新的地壳运动方向图和块体运动模型.通过与NNR-NUVEL1A地质模型比较认为,ITRF97板块运动模型反映了现今十几年跨度的地壳运动,在研究我国现今几年到十几年时间跨度的地壳形变时,地壳运动背景场应采用基于ITRF97实测速度场建立欧亚板块运动模型.     

西北地区东部重要天气预报业务系统

利用实时资料和数值预报产品,建立以多种数据库为支撑的西北地区东部重要天气预报业务系统。该系统在本地灾害性、关键性和转折性天气的中短期预报方面具有较好的业务实用效果。