星系结构和动力学

从星系形成和演化的角度出发，对星系结构和动力学进行的粗略的评述，内容包括：（1）初步描述了星系中各主要成分的物理特征（空间分布，运行学和化学）及其形成和演化，（2）Damped Lyman-alpha systems(DLAs)是本地星系的化石，对其进行观测研究是HST的主要任务之一，对DLAs宽的谱线轮廓的物理机制和其恒星形成，化学演化进行了讨论，（3）目前已证明Lyman Break方法是发现高红移高恒星形成星系的有效手段，讨论了Lyman Break Galaxies的动力学过程和恒星形象，（4）旋涡星系和椭圆星系的Scaling Law是星系形成和演化所必须解释的问题，对近期该方面的研究结果作了介绍，（5）整体超星的反馈作用在星系形成和演化中起了重要作用，评述了该物理过程对星系演化的影响；（6）随着观测资料的不断积累，各种物体对河外背景辐射的贡献已成了一个重要的研究方向，讨论了宇宙整体的星形成历史和化学演化，（7）银河系是进行星系形成和演化研究的归算零点，介绍了银河系的结构，动力学及演化。     

类星体和星系的关系

本文从类星体与星系成协、类星体是遥远的星系核以及类星体跟活动星系,正常星系形成一个活动程度的明显序列等方面,评述了类星体和星系的关系。这些关系是否意味着类星体和星系有演化上的联系,还有待从观测和理论上作进一步研究。     

核盘晕星系相互作用的模拟研究

用一个星系相互作用数值模拟的综合三体模型，研究椭圆星系是否由盘星系合并而成，结果表明，主要取决于星系的盘面积和星系运行轨道面的夹角，如果夹角不等于零，盘星系的相互作用是可能形成椭圆星系的，否则还是盘星系。     

Virgo星系团的光度函数和质量函数

本文对Ｖｉｒｇｏ星系团中央６°天区内的成员星系作了光度函数和质量函数的研究。成员星系是以视向速度作为判据并合理地考虑了密度分布因素后确定的。研究表明，该天区全部成员星系的光度函数为Ｓｃｈｅｃｈｔｅｒ型，而各类Ｓ星系的光度函数则为Ｇａｕｓｓ型，且峰值位置按Ｓａ→Ｓｄ序列向暗端移动，宽度亦逐渐变宽；Ｖｉｒｇｏ团质量函数与恒星质量函数一样可以用指数形式来描述，文中还利用光度函数和质量函数对该团的形态和质量分层进行了讨论，并计算了该天区团的总光度。     

宇宙信息

宇宙信息分辨出矮旋涡星系哈勃星系分类法根据星系的外形将“正常”星系分成椭圆星系。透镜星系、旋涡星系和不规则星系。此分类法也适用于矮星系，矮星系是光度和质量都小的星系，绝对星等一般为一８—一１６等；质量一般为１０６～１０９太阳质量。矮星系中多数为椭圆星...     

核盘晕星系相互作用的模拟研究

用一个星系相互作用数值模拟的综合三体模型，研究椭圆星系是否由盘星系合并而成。结果表明，主要取决于星系的盘面和星系运行轨道面的夹角。如果夹角不等于零，盘星系的相互作用是可能形成椭圆星系的，否则还是盘星系。     

星系之谜四则

星系之谜四则许梅１９２６年，美国天文学家哈勃（Ｅ．Ｈｕｂｂｌｅ），对星系光谱线红移的发现开创了天文学的一个重要分支──星系天文学。７０年来，虽然对形形色色的星系积累了大量的观测资料，但有关星系的很多问题仍未搞清楚，如星系的起源与演化、星系的能源、星系...     

盘星系的内禀扁度研究

盘星系的内禀扁度对计算星系的空间倾角非常重要．对从LEDA数据库中选取的14988个盘星系进行内禀扁度的统计分析．研究表明，盘星系的内禀扁度与星系的形态密切相关．整体上说，透镜星系和不规则星系的内禀扁度qo大于旋涡星系，早型旋涡星系的内禀扁度qo大于晚型旋涡星系，其中Scd星系的内禀扁度qo最小．利用所得的qo-T关系，还对16个已知倾角的亮星系进行了倾角计算，发现与其他方法估计的空间倾角符合得较好．     

极亮红外星系和活动星系核(英文)

介绍了我们对极亮红外星系研究的系列工作。这些工作包括对星系并合激发星暴和星系核活动并最终形成椭球星系的演化过程。特别介绍了星系多重并合的观测证据和IRQSO与窄线Seyfert 1(NLS1)、低电离宽吸收线类星体之间可能的演化关系     

星系的转动与黑洞形成的判据

本文通过数值计算解出稳态星系模型，并与椭圆星系及旋涡星系核球的自转和弥散速度曲线相比较。由星系运动曲线传合出的星系半径与从光度曲线拟合出的潮汐半径不一致，后者总是前者的３倍左右，这是由于分布函数的截断方式不妥造成的。我们的结论是：该模型虽不能正确描述整个星系，但却能正确描述星系的较内部区域。我们分析了三个速度曲线资料的星系黑洞候选者：Ｍ１０４、Ｍ３１和银河系，发现它们由于有太快的自转，都不可能在达     

The structure of polar caps and the equatorial belt of pulsars

The self-consistent balanced pulsar magnetosphere of a magnetic neutron star with aligned magnetic and rotational axes is considered. It is shown that the magnetosphere consists of electron polar caps separated by empty space from a positron equatorial belt. The shape of the cold polar caps at a large distance from the star is calculated. It is shown that the cap shape at a large distance is independent of the magnetospheric structure near the neutron star. The shape of the equatorial belt is calculated. It is shown that a part of the equatorial belt rotates differentially, and its angular velocity is larger than that of the star (superrotation). It is shown that under certain conditions the space charge density of the belt can be very large. In principle, the formation of a surface charge placed in vacuum on a magnetic surface is possible. Magnetospheric vibrations are considered. A connection is established between drifting subpulses and the equatorial belt superrotation and also between drifting subpulses and cap vibrations. The characteristic frequency of vibrations and the angular velocity of superrotation are estimated.     

原太阳吸积盘结构

计算了粘滞演化阶段原太阳吸积盘结构。采用稳态标准吸积盘模型来描述盘中湍动粘滞；忽略其径向能量传输，将垂直结构作为一维问题处理。假设盘作Keplerian较差旋转，处于流体力学平衡和局域热平衡，盘由粘滞耗散加热，能量通过对流和辐射向外传输。结果表明，对温度敏感的不透明度是决定盘结构的重要因素；原太阳吸积盘为冷的薄盘，盘中热对流不稳定性由外而内，由上而下地终结；行星的形成应首先开始于对流终结的区域。     

应用于射电天文的低噪声温度测量方法

噪声温度是接收机和低噪声放大器最重要的性能指标,是了解设备性能好坏的关键因素。随着电子技术的快速发展,接收机和低噪声放大器的噪声温度变得越来越低,准确而快速地测量接收机和低噪声放大器的噪声温度变得非常困难。介绍了6种在射电天文中经常使用的测量低噪声温度的方法,这些测量方法具有准确可靠、简单易行的优点。叙述了测量原理并给出了一些测量方法的测量结果,对影响测量噪声温度精度并且易被忽视的因素也做了详细讨论。     

网络时延对网上高时间约束业务影响的讨论

给出了一系列的网络测量结果。通过对实测结果的分析，结合图表形象地揭示了网络时延的严重性、随机性和信息路径的不确定性，指出了这种网络现象对具有高时间约束的网络通信业务的严重影响，并阐述了测量和改正网络时延的重要意义。     

A new regularization of the restricted three-body problem and an application

A new regularizing transformation for the three-dimensional restricted three-body problem is constructed. It is explicitly derived and is equivalent to a simple rational map. Geometrically it is equivalent to a rotation of the 3-sphere. Unlike the KS map it is dimension preserving and is valid inn dimensions. This regularizing map is applied to the restricted problem in order to prove the existence of a family of periodic orbits which continue from a family of collision orbits.     

On the interpretation of the photometry of irregular variable stars observed intermittently

This note is concerned with the inherent possibilities and limitations in the characterisation of irregular variables when, as is almost inevitably the case, the observations are not effectively continuous. The historical tendency to interpret almost everything in terms of strict periodicity is criticised. The basic logic of the situation is discussed, and it is emphasised that intermittency of observation inevitably blunts our knowledge of the spectrum of the variation. This can be restored to only a limited extent, depending on how reliably it is possible to presume missing observations by interpolation. Some applcation is made to a recent publication on 3C 345.A knowledge of formal Fourier theory is assumed, and the aim is to discuss critical principles rather than to recommend any fixed procedures of interpretation.     

Some physical properties and stability of an exact model of a relativistic star

An exact solution of Einstein's field equations for an isentropic fluid sphere is examined. It turns out that the crucial factor for the physical properties and the stability of this model is the degree of incompressibility. Necessary and sufficient conditions are given for the weak and the strong energy conditions to be fulfilled and for the speed of sound to be less than the speed of light. The speed of sound always has a minimum at the center of the fluid sphere. But two possibilities exist: either the speed of sound is increasing all the way outwards to the surface of the sphere, or the speed of sound is first increasing, then reaching a maximum when still inside the fluid sphere, and thereafter decreasing outwards to the surface. The adiabatic index is investigated and is found to be increasing outwards for the actual degrees of compressibility. This adiabatic index is always greater than unity, and the temperature is thus decreasing throughout the sphere. The necessary and sufficient condition for the adiabatic index to be greater than 4/3 is also given. (This is a necessary condition for the fluid sphere to be stable.) Chandrasekhar's pulsation equation with boundary conditions is investigated, and the fluid sphere is found to bestable if and only if the degree of incompressibility is greater than a certain value.Dedicated to the memory of the late Bronislaw Kuchowicz.     

中国古代彗星记录的证认

对中国古代彗星记录的研究状况进行了全面论述,讨论了古代彗星名称、记录和轨道的确定,以事实说明,据这些彗星记录不可能得垤精确的轨道;回顾了古代彗星证认的历史发展,着重分析进行短周期彗得证认时可能出现的问题和解决方法;总结了古代彗星证认的意义：一是有助于短周期彗星长期演化的研究,二是有助于历史年代的确定。     

Conditions for Propagation of Torsional Waves in Solar Magnetic Flux Tubes

Propagation of torsional waves along isothermal and initially-untwisted magnetic-flux tubes embedded in the solar atmosphere is studied analytically. Conditions for wave propagation along thin and wide magnetic-flux tubes are determined, and it is shown that the propagation along thin tubes is cutoff free; however, for wide tubes the propagation is affected by a cutoff frequency. A method to determine the cutoff frequency is presented and applied to a specific model of solar magnetic flux tubes. An interesting result is that the cutoff frequency is a local quantity in the model and that its value at a given height determines the frequency that torsional tube waves must have to propagate at this height.     

Active Optics in LAMOST

Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is one of the major national projects under construction in China. Active optics is one of the most important technologies for new large telescopes. It is used for correcting telescope errors generated by gravitational and thermal changes. Here, however, we use this technology to realize the configuration of LAMOST, -a task that cannot be done in the traditional way. A comprehensive and intensive research on the active optics used in LAMOST is also reported, including an open-loop control method and an auxiliary closed-loop control method. Another important development is in our pre-calibration method of open-loop control, which is with some new features: simultaneous calculation of the forces and displacements of force actuators and displacement actuators; the profile of mirror can be arbitrary; the mirror surface shape is not expressed by a fitting polynomial, but is derived from the mirror surface shape formula which is highly accurat