IERS综合河外射电源表的检验

本文对ＩＥＲＳ综合河外射电源表进行了检验，指出１９８８至１９９１各年度的ＩＥＲＳ综合河外射电源表中均存在坐标系统不一致问题，部分射电源的位置坐标中带有几个毫角秒的偏差，与公认精度不符。坐标系统不一致问题影响了ＩＥＲＳ综合表的指向维持，使此维持仅限于数学意义上的平均水平，失去了明确的物理意义。     

IERS综合河外射电源表的检验

本文对ＩＥＲＳ综合河外射电源表进行了检验，指出１９８８至１９９１各年度的ＩＥＲＳ综合河外射电源表中均存在坐标系统不一致问题，部分射电源的位置坐标中带有几个毫角秒的偏差，与公认精度不符，坐标系统不一致问题影响了ＩＥＲＳ综合表的指向维持，使此维持仅限于数学意义上的平均水平，失去了明确的物理意义。     

脉冲星时间尺度及其TOA预报初步分析

在简述国际天文学会(IAU)定义的几种不同时间尺度的基础上,重点讨论脉冲星计时观测中时间坐标相对论转换问题。脉冲星计时观测资料分析应该参考地球时TT,并将TT转换为质心坐标时TCB或质心力学时TDB。基于IAU重新定义的TDB,讨论和比较了时间坐标转换的解析算法和利用太阳系天体历表的数值积分算法。分析了TCB和TDB对脉冲星自转参数测量的影响。最后,以毫秒脉冲星PSR B1855+09的计时模型为例,初步分析了脉冲星脉冲到达时间的预报问题。     

区域GPS网实时计算可降水量的若干问题

目前地基GPS气象学测得的可降水量(PWV)精度好于2mm，但在利用区域GPS网实时计算每个测站上空的PWV时，要涉及到很多常规GPS资料处理时所忽略的问题，如需考虑数据处理软件和计算方式的选择、站坐标的确定和约束、轨道的使用方法、网外辅助站最佳数量的确定、海潮对实时计算PWV的影响以及实时应用于气象服务时的端部效应等问题。利用上海GPS综合应用网获取的2002年6、7月份长江三角洲地区人梅前后的数据，分析了利用区域性的GPS网实时计算高精度的PWV时要解决的各种问题，探讨了其数据处理方案。     

太阳大气中磁重联的MHD数值模拟

回顾了近３０年太阳大气中磁重联过程的ＭＨＤ数值模拟工作取得的进展。着重描述了在验证理论模型,解释观测现象,以及研究各种因素对重联的影响三个方面的成果,如快速磁重联,太阳耀斑机制及色球,日冕中的各种爆发现象等。指出了在数值模拟中应注意的几个问题,并对该领域今后的发展作了简要的展望。     

球状星团系统的比频、金属度和质量谱

评述了球状星团系统研究中的比频、金属度和质量谱三大问题，就目前的认识和存在的问题进行了讨论。指出不同星系球状星团比频之间的差别表明了需要有各种不同的球状星团形成模型；球状星团金属度的分布表明球状星团可能有三个形成时期，分别与三类形成模型效应；尽管对数正态初始质量的数值模拟初步结果与观测结果符合得更好，然而幂函数的初始质量谱在物理上能很好地与球状星团形成联系起来。     

世界时的概念还需要吗

地球自转速度的不均匀性的存在使传统的世界时的概念变得复杂、模糊和不精确。引进赤道上的无旋转原点代替历书春分点并不能使上述问题得到解决。世界时曾在三个方面起过作用：（1）提供一个均匀的时间尺度；（2）是描述地球参考系和天球参考系之间关系的参数之一；（4）为协调时UTC跳秒提供依据。这里的第一项作用早已被国际原子时尺度所取代。第二项作用可以由恒星时更直接更简单地实现。第三项作用可通过恒星时与“坐标恒星时”之差的测定来实现。因此，作者认为，世界时这一传统概念已无继续存在的必要，长期以来由于世界时的概念所引进的各种矛盾只有在抛弃世界时的概念后才能和彻底解决。     

Kuiper带小天体动力演化

Kuiper带是指太阳系内位于离太阳30－50AU一个区域。1992年该区域陆续发现了一群半径在几十到几百公里的小天体。这些小天体在Kuiper带的分布是极其不均匀的。Kuiper带小天体的发现对人们认识太阳系的形成与演化有重要的意义。本文回顾了近年来国际上在Kuiper带小天体动力演化方面的研究，着重分析了目前国际上几种用以解释其非均匀分布的动力学机制，并提出目前该领域的一些尚未解决的问题。     

中国虚拟天文台研发策略与重点

由于不同的天文和技术背景，不同的虚拟天文台项目采取了不同的研究策略。本文首先介绍了国际上几个典型虚拟天文台项目的研发目标和工作重点；然后讨论了包括中国虚拟天文台在内的小型虚拟天文台项目在研发方面的优势和劣势。中国虚拟天文台项目根据自身所处的具体情况确定自己将走应用路线，争取在某些领域取得突破，研发重点包括五个方面：China-VO系统平台建设、国内外天文数据的统一访问、现有天文工具的虚拟天文台集成、天文设备的虚拟天文台集成、虚拟天文台基础上的公众教育。     

冕洞观测研究的近期进展

简要介绍了在１９８８－１９９５年期间冕洞观测研究的主要进展。文中共分五个方面：１．冕洞磁场观测研究的新进展；２．冕洞在太阳活动周不同位相时的规律性；３．冕洞区高速太阳风观测的新结果；４．冕洞加热问题；５．存在问题。     

高精度国际时间比对的进展

在过去的４５ｙｒ中原子频标的性能大约每７ｙｒ提高一个数量级,从国际标准时间和各国高精度守时的需要出发,远距离的高精度时间频率传递比对技术也有与之相适应的很大的发展。ＧＰＳ卫星在近２０ｙｒ中不仅成为导航定位不可缺少的工具,在时间、频率的方面也发挥出巨大威力;近年来多通道“全视接收”技术的发展钎时频传输比对的稳定性有了重大改善;ＧＬＯＮＡＳＳ卫星系统在高精度时间比对方面正在成为ＧＰＳ系统的重要补充手段     

Concluding remarks and perspectives on the evolution and seismic tools activity (ESTA) of the CoRoT community

A first part gives a summary of the main conclusions stemmed from the different comparisons reported in this book. One main conclusion is: with some care in the computations, one is able to obtain frequency differences between different computations which are smaller than required by Corot challenges. This is true for high frequency modes. Small frequency differences are much less easily obtained for low frequencies around the fundamental radial mode frequency. Care here means: having the same physics, same constants of physics, same input stellar parameters, computing models and oscillations with enough self numerical consistent accuracy. The ESTA group has built reference grids of models and associated oscillation frequencies and made them available to the community. In a second part of the present paper, a study case is considered in order to show the need and the use of such reference grids. Finally some perspectives concerning the remaining tasks are suggested.     

基于DS1624的多点温度监测系统

为了减少温度变化对高精度时间比对的影响,设计了一种由带存储功能的数字温度计DS1624构建的、基于I2C总线的温度监测系统,并给出了系统的构成及软件、硬件实现方法和详细实验结果。分析表明,以温度监测系统为关键部分的温度控制系统是高精度时间比对所必要的。     

Distribution of magnetic flux on the solar surface and low-degree p-modes

The frequencies of solar p-modes are known to change over the solar cycle. There is also recent evidence that the relation between frequency shift of low-degree modes and magnetic flux or other activity indicators differs between the rising and falling phases of the solar cycle, leading to a hysteresis in such diagrams. We consider the influence of the changing large-scale surface distribution of the magnetic flux on low-degree ( l ≤3) p-mode frequencies. To that end, we use time-dependent models of the magnetic flux distribution and study the ensuing frequency shifts of modes with different order and degree as a function of time. The resulting curves are periodic functions (in simple cases just sine curves) shifted in time by different amounts for the different modes. We show how this may easily lead to hysteresis cycles comparable to those observed. Our models suggest that high-latitude fields are necessary to produce a significant difference in hysteresis between odd- and even-degree modes. Only magnetic field distributions within a small parameter range are consistent with the observations by Jiménez-Reyes et al. Observations of p-mode frequency shifts are therefore capable of providing an additional diagnostic of the magnetic field near the solar poles. The magnetic distribution that is consistent with the p-mode observations also appears reasonable compared with direct measurements of the magnetic field.     

基于伪距测量的钟差计算模型

基于伪距和钟差定义,讨论了无线电时间比对的基本原理。在此基础上,详细推导了地心非旋转坐标系中一般意义下基于伪码测距模式的钟差计算模型,并通过坐标变换,给出了地固系中的实用计算模型。对地回系计算模型的进一步分析表明：卫星在地固系运动速度引起的改正项与sagnac效应项是完全不同的两项改正;对于GEO卫星,sagnac效应项最大约为200ns,其地固系运动速度引起的改正约为1ns;而对于MEO卫星,sagnac效应项最大为120ns,其地固系运动速度引起的改正约为1200ns。     

Three-Dimensional Reconstruction of Two Solar Coronal Mass Ejections Using the STEREO Spacecraft

Previous attempts to produce three-dimensional (3-D) reconstructions of coronal mass ejections (CMEs) have required either modeling efforts or comparisons with secondary associated eruptions near the solar surface. This is because coronagraphs are only able to produce sky-plane-projected images of CMEs and it has hence been impossible to overcome projection effects by using coronagraphs alone. The SECCHI suite aboard the twin STEREO spacecraft allows us to provide the means for 3-D reconstruction of CMEs directly from coronagraph measurements alone for the first time. We present these measurements from two CMEs observed in November 2007. By identifying common features observed simultaneously with the LASCO coronagraphs aboard SOHO and the COR coronagraphs aboard STEREO we have triangulated the source region of both CMEs. We present the geometrical analysis required for this triangulation and identify the location of the CME in solar-meridional, ecliptic, and Carrington coordinates. None of the two events were associated with an easily detectable solar surface eruption, so this triangulation technique is the only means by which the source location of these CMEs could be identified. We present evidence that both CMEs originated from the same magnetic structure on the Sun, but from a different magnetic field configuration. Our results reveal some insight into the evolution of the high corona magnetic field, including its behavior over time scales of a few days and its reconfiguration after a major eruption.     

时间传递接收机天线坐标的检测方法

讨论利用全球定位系统 (GPS)共视观测数据 (GGTTS格式 )测定接收机天线坐标的原理和方法 ,采用此方法 ,发现日本国家计量研究院 (NRLM )、墨西哥国家计量院 (CNM )、土耳其国家计量院 (UME)在进行TAIGPS共视观测时采用的GPS接收机天线坐标存在明显偏差。经坐标偏差改正后 ,日本国家计量研究院与日本通信综合研究所 (NRLM CRL)、墨西哥国家计量院与美国国家标准、技术研究院 (CNM NIST)、土耳其国家计量院与法国巴黎天文台 (UME OP)的比对精度分别由 1 8.6ns、7.0ns、2 83.0ns提高到 3.0ns、4 .5ns、4 .7ns。     

Time Lags between the 22 and 37 GHz Bursts of 48 Radio-loud AGNs

Based on the light curves at 22 and 37 GHz from the Metsahovi monitoring pro-gram, we investigate the time lags between the two radio bands for 48 radio-loud AGNs. DCF and ZDCF analyses are applied to the data. Our results show that there is a strong correlation between the two radio frequencies for all the sources, with the variations in the light curvesat 37 GHz leading the ones at 22 GHz in general. There is no obvious differences between different sub-class AGNs as regards the time lag. In two sources, it was found that the bursts at the lower frequency lead the ones at the higher frequency. One possible explanation is that electron acceleration dominates the light curve until the radiation reaches the maximum. Some sources, such as 3C 273, 3C 279, 3C 345 and 3C 454.3, have good enough data, so we can calculate their lags burst-by-burst. Our calculations show that different outbursts have dif- ferent lags. Some bursts have positive lags, most of bursts have no clear lags, and a few have negative lags. This result means that different bursts are triggered by different mechanisms, and the interpretation for the result involves both an intrinsic and a geometric mechanism. The positive lags are well consistent with the shock model, and we use these lags to calculate the typical magnetic field strength of the radiating region.     

GPS载波相位在频率测量中的应用

讨论了载波相位测量在频率对比测量中的应用方法与可能遇到的问题,以及该方法所能达到的测频精度。     

脉冲星时稳定度及可能应用

给出了毫秒脉冲星长期计时观测最新结果和脉冲星时与原子时频率稳定度的比较。指出脉冲星时频率稳定度的提高受到计时观测误差的限制,讨论了提高毫秒脉冲星计时观测精度的方法。随着脉冲星计时阵的实施,脉冲星时的应用已为期不远。可能的应用包括毫秒脉冲星与原子钟结合守时、建立综合脉冲星时和用脉冲星计时阵检测原子时误差等方面。