Rapid periodic light variations of EM Cephei

In 1990 and 1992, using the 60 cm reflector of Beijing Observatory, we carried out photoelectric UBV observations of the Be star EM Cep and obtained 277 data sets. After combining the published minimum times over the years we made the O — C analysis and found an improved period of 0.806184 d or a single wave period of 0.403092d. Our analysis also showed a quickening tendency of the period at a rate dP/dt = −8.8514 × 10⁻¹⁰. The light curve is characterized by sharp minima and broad maxima. We found a detectable variation of the U — B colour index with the phase.     

Global properties of star formation in spiral galaxies

Samples of spiral galaxies from two catalogues of 21 cm line observations and a catalogue of near-infrared observations of nearby galaxies have been used in conjunction with Infrared Astronomical Satellite data to study correlations involving M_G, the dynamic mass of the galaxies, the luminosities in theH band (1.6Μm), the blue band and the far infrared bands and the mass of atomic hydrogen, it is found that both the blue and the far-IR luminosities which are indicators of star formation averaged over ∼3 × l0⁹ and ∼10⁷ years respectively, have a linear dependence onM _G On the other hand, theH luminosity which is a measure of star formation averaged over the lifetime of galaxies, has a steeper power law dependence onM _G. The correlations observed do not have significant dependence on the morophological type of the galaxies There is a poor correlation between the far-infrared luminosity and the mass of atomic hydrogen. The mass of atomic hydrogen has a dependence of the formM _G. Because of the decrease in the mean mass for later morphological types and due to differences in power law dependences of luminosities in different bands onM _G, the mean value of luminosity-to-mass ratio is a constant for blue and far-IR bands, decreases for theH band and the gas-to-mass ratio increases as morphological type increases.     

HD229221：一颗具有独特的H_α变化的主序前恒星

作者在对年轻疏散星团ＮＧＣ６９１３的观测中发现一颗具有独特Ｈ_α谱线形状变化的天体，本文对观测资料进行了初步的分析。     

白山拱坝位移激光监测自动化系统研究

提出用半导体激光发射器结合位敏传感器进行位移测量和利用光学测角仪进行倾角观测的方法解决拱坝变形观测问题。对激光监测自动化系统进行了原理分析、算法推导、精度评定。在白山拱坝的实践表明：本系统精度高，自动化效果好，具有较好的推广价值。     

我国流动SLR首次取得观测成果

介绍了流动SLR系统TROS建成后在北京，乌鲁木齐，拉萨3个站的观测情况。这是流动卫星光测距系统在我国首次正式运行，开创了SLR流动观测的先例，实现了我国SLR领域多年来的愿望。对乌鲁木齐和世界屋脊城市拉萨观测的实现有其重要意义，引起国内外广泛关注。对TROS的建站和观测等问题进行了讨论，给出了观测结果。     

恒星形成时期强远红外源中的22GHz水脉发射与CO分子外向流关系的研究

为揭示大质量星形成及早期演化中的一些重要特征，根据ＩＲＡＳ的流量，选择了一批Ｆ１００μ≥５００Ｊｙ的强远红外源，它们大多是处于恒星形成或早期演化阶段中的大质量的天体，利用紫金山天文台青海观测站１３．７米射电望远镜，对它们进行了２２ＧＨｚ水脉泽的搜寻，得最１１个新的水脉泽源。     

利用SLR资料解算武汉—上海基线长度及结果分析

运用动力学原理，利用全球１９８８、１９９０、１９９１等年份的部分ＬＡＧＥＯＳ卫星激光测距资料解算武汉—上海的基线长度为６５７４９７．０５０７ｍ，内符合精度优于２ｃｍ，相对精度为４×１０－８，与ＩＥＲＳ公布的结果接近。计算结果分析表明武汉ＳＬＲ站的第三代测距仪运行系统稳定，没有明显的系统误差