类星体Lyα吸收线密度与其发射线红移的关系

本文利用７２个具有中等分辨率的类星体Ｌｙα线资料，研究了Ｌｙα吸收线数密度Ｎ（Ｚａｂｓ）与类星体发射红移Ｚｅｍ的变化关系，结果表明：对于Ｚｅｍ越大的类星体其全部Ｌｙα吸收线的平均数密度Ｎ（Ｚａｂｓ）也越大，但对于相同的吸收红移值而言，Ｎ（Ｚａｂｓ）在统计意义上与Ｚｅｍ并无关系。本文还将所得结果与其他的有关工作作了比较及讨论。     

Type III burst pair

We present a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0–2.0 GHz) of the Beijing Astronomical Observatory (BAO). Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. We call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is a nice interpretation of type III burst pair since the plasma beta 0.01 is much less than 1 and the beams have velocity of about 1.07×10⁸ cm s^–1 after leaving the reconnection region if we assume that the ambient magnetic field strength is about 100 G.     

2.63.8GHZ太阳微波爆发中的精细结构

微波Ⅲ型爆发和微波尖峰辐射是太阳微波爆发中两个主要的精细结构,由于微波段比长波段的情况更复杂,单从形态上很难区分。１９９４ 年Ｉｓｌｉｋｅ ＆ Ｂｅｎｚ 给出１３ＧＨｚ 频带上的各类爆发分类定义,本文参考了其中关于微波Ⅲ型爆发和微波尖峰辐射的分类,分析北京天文台２ ．６３ ．８ＧＨｚ 频带上观测到的微波尖峰辐射的精细结构,发现该定义有局限性,重新定义了本波段上的微波Ⅲ型爆发和微波尖峰辐射,并讨论了这种分类定义与设备时间分辨率的关系     

High Spatial Resolution X-Ray Spectroscopy of Cas A with Chandra

We present high spatial resolution X-ray spectroscopy of the supernova remnant Cassiopeia A with the Chandra observations. The X-ray emitting region of this remnant was divided into 38 × 34 pixels of 10″× 10″ each. Spectra of 960 pixels were created and fitted with an absorbed two component non-equilibrium ionization model. From the results of the spectral analysis we obtained maps of absorbing column density, temperatures, ionization ages, and the abundances of Ne, Mg, Si, S, Ca and Fe. The Si, S and possibly Ca abundance maps show obvious jet structures, while Fe does not follow the jet but seems to be distributed perpendicular to it. The abundances of Si, S and Ca show tight correlations between one another over a range of about two dex. This suggests that they are ejecta from explosive Oburning and incomplete Si-buming. Meanwhile, the Ne abundance is well correlated with that of Mg, indicating them to be the ashes of explosive C/Ne burning. The Fe abundance is positively correlated with that of Si when the latter is lower than 3 times the solar value, and is negatively correlated when higher. We suggest that such a two phase correlation is due to the different ways in which Fe was synthesized.     

A GRB Follow-up System at the Xinglong Observatory and Detection of the High-Redshift GRB 060927

A gamma-ray burst (GRB) optical photometric follow-up system at the Xinglong Observatory of National Astronomical Observatories of China (NAOC) has been constructed. It uses the 0.8-m Tsinghua-NAOC Telescope (TNT) and the 1-m EST telescope, and can au-tomatically respond to GRB Coordinates Network (GCN) alerts. Both telescopes slew rela-tively fast, being able to point to a new target field within ～ 1 min upon a request. Whenever available, the 2.16-m NAOC telescope is also used. In 2006 the system responded to 15 GRBs and detected seven early afterglows. In 2007 six GRBs have been detected among 18 follow-up observations. TNT observations of the second most distant GRB 060927 (z = 5.5) are shown, which started as early as 91 s after the GRB trigger. The afterglow was detected in the combined image of the first 19 × 20 s unfiltered exposures. This GRB follow-up system has joined the East-Asia GRB Follow-up Observation Network (EAFON).     

XUV Photometer System (XPS): Improved Solar Irradiance Algorithm Using CHIANTI Spectral Models

Solar soft X-ray (XUV) radiation is highly variable on all time scales and strongly affects Earth’s ionosphere and upper atmosphere; consequently, the solar XUV irradiance is important for atmospheric studies and for space weather applications. Although there have been several recent measurements of the solar XUV irradiance, detailed understanding of the solar XUV irradiance, especially its variability during flares, has been hampered by the broad bands measured in the XUV range. In particular, the simple conversion of the XUV photometer signal into irradiance, in which a static solar spectrum is assumed, overestimates the flare variations by more than a factor of two as compared to the atmospheric response to the flares. To address this deficiency in the simple conversion, an improved algorithm using CHIANTI spectral models has been developed to process the XUV Photometer System (XPS) measurements with its broadband photometers. Model spectra representative of quiet Sun, active region, and flares are combined to match the signals from the XPS and produce spectra from 0.1 to 40 nm in 0.1-nm intervals for the XPS Level 4 data product. The two XPS instruments are aboard NASA’s Solar Radiation and Climate Experiment (SORCE) and Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) satellites. In addition, the XPS responsivities have been updated for the latest XPS data processing version. The new XPS results are consistent with daily variations from the previous simple conversion technique used for XPS and are also consistent with spectral measurements made at wavelengths longer than 27 nm. Most importantly, the XPS flare variations are reduced by factors of 2 – 4 at wavelengths shorter than 14 nm and are more consistent, for the first time, with atmospheric response to solar flares. Along with the details of the new XPS algorithm, several comparisons to dayglow and photoelectron measurements and model results are also presented to help verify the accuracy of the new XUV irradiance spectra.     

锆石氧逸度对义敦岛弧南段中甸矿集区斑岩型矿床差异性成矿控制因素的指示

中甸铜钼多金属矿集区位于义敦岛弧南段,区内绝大多数矿床与晚三叠世和晚白垩世岩浆活动有关,目前两期斑岩锆石氧逸度及差异性成矿研究薄弱.对4个斑岩体5类岩石的锆石开展LA-ICPMS微量元素分析,数据经筛选检验后进行了氧逸度估算.氧逸度结果由高到低为:地苏嘎铜矿晚三叠世石英闪长玢岩(Ce4+/Ce3+比值为515)、休瓦促...     

瞬时偏振滤波技术压制X分量中的面波(英文)

瑞雷面波与体波在偏振上的差异使得利用偏振特征分离这两种波场成为可能。为克服滑动时窗法在应用中存在的一些问题,本文将工程地震和天然地震信号分析中的复数道技术与瞬时偏振分析技术引进到能源领域多分量地震勘探转换波记录中的面波压制处理。理论模拟与野外实测数据的处理试验显示了较好的压制面波、保留有效信号的去噪效果,证明了该技术值得在多分量数据处理中推广应用。     

椒江口潮间带大型底栖动物群落beta多样性分析

于2007年10月在椒江口共布设6条潮间带采样断面,每条断面在中潮带上区、中区、下区和低潮区各设1站位进行大型底栖动物采样。分析了不同采样站位数与大型底栖动物种数的关系,选用Wilson-Shmidabeta多样性测度方法,对以下3种空间环境梯度下大型底栖动物群落beta多样性进行了研究:(1)断面内垂直环境梯度;(2)河流到海洋的环境梯度;(3)河口两岸间的距离梯度。分析了不同采样站位数对群落beta多样性指数的影响,结果显示:(1)随着采样站位数的增加,物种数呈增加趋势但增速渐慢,同时beta多样性指数呈下降趋势;(2)不同的潮区间隔下的be-ta多样性指数均有显著差异;(3)在北岸和南岸,随着断面间距的增加beta多样性指数均呈升高趋势,而且与各断面的沉积物粒度、油类含量呈显著相关;(4)椒江口为喇叭形河口,随着河口两岸断面距离的增加beta多样性指数呈升高趋势。