利用F10.7和Mg II构建太阳极紫外辐射长时间序列

利用SOHO/SEM在1996-2008年的太阳EUV观测数据,比较和评估F10.7和Mg II作为EUV代理参数的代表性,不能支持Viereck等关于Mg II是比F10.7更好的代理参数的结论.通过比较对两种参数的多种回归计算结果,确立双因子极大似然估计方法构建EUV计算模式,通过模型计算结果与SEM观测数据比较,表明该模型能够很好地重建EUV数据系列.利用该模式,构建了1978年11月以来的太阳极紫外辐射数据序列.     

Local, global and virtual buzz: The importance of face-to-face contact in economic interaction and possibilities to go beyond

Novel information and communication technologies have created new possibilities for transferring information and knowledge over distance. Although this might open up broad options for economic interaction, knowledge regarding the effects of these changes on the geographies of production and innovation is still incomplete. Under these circumstances, permanent co-location and face-to-face (F2F) interaction may be efficient in some contexts but not in others. Support by computer-mediated communication (CMC), temporary, and virtual interaction is increasingly becoming the basis for establishing trans-local production networks. By combining results from social psychology with economic geography, it is argued that there is no generally superior spatial fix for economic interaction. Different spatial configurations can be advantageous in different production and innovation contexts, even over large distances without permanent or even regular F2F contact. This paper systematically investigates the effects of new communication technologies and different organisational forms for economic interaction by emphasizing the potential of combining CMC with forms of temporary and permanent F2F interaction.     

Modelling F2-layer seasonal trends and day-to-day variability driven by coupling with the lower atmosphere

This paper presents results from the TIME-GCM-CCM3 thermosphere–ionosphere–lower atmosphere flux-coupled model, and investigates how well the model simulates known F2-layer day/night and seasonal behaviour and patterns of day-to-day variability at seven ionosonde stations. Of the many possible contributors to F2-layer variability, the present work includes only the influence of ‘meteorological’ disturbances transmitted from lower levels in the atmosphere, solar and geomagnetic conditions being held at constant levels throughout a model year.In comparison to ionosonde data, TIME-GCM-CCM3 models the peak electron density (NmF2) quite well, except for overemphasizing the daytime summer/winter anomaly in both hemispheres and seriously underestimating night NmF2 in summer. The peak height hmF2 is satisfactorily modelled by day, except that the model does not reproduce its observed semiannual variation. Nighttime values of hmF2 are much too low, thus causing low model values of night NmF2. Comparison of the variations of NmF2 and the neutral [O/N₂] ratio supports the idea that both annual and semiannual variations of F2-layer electron density are largely caused by changes of neutral composition, which in turn are driven by the global thermospheric circulation.Finally, the paper describes and discusses the characteristics of the F2-layer response to the imposed ‘meteorological’ disturbances. The ionospheric response is evaluated as the standard deviations of five ionospheric parameters for each station within 11-day blocks of data. At any one station, the patterns of variability show some coherence between different parameters, such as peak electron density and the neutral atomic/molecular ratio. Coherence between stations is found only between the closest pairs, some 2500 km apart, which is presumably related to the scale size of the ‘meteorological’ disturbances. The F2-layer day-to-day variability appears to be related more to variations in winds than to variations of thermospheric composition.     

A climatological study of nocturnal equatorial F-region irregularities at the west Pacific longitudes by using phase fluctuations of the global positioning system

This study investigated a long-term climatology of nocturnal equatorial F-region irregularities by using phase fluctuations of the global positioning system during the solar cycle of 1996–2006 at the west Pacific longitudes. The results showed that the distribution of the occurrence of irregularities is a two-peak pattern, which peaks in equinoxes with a shallow/deep dip in June/December solstice during high solar activity but with two about the same dips in magnitude in both June and December solstices during low solar activity. Moreover, the most interesting longitudinal effect in the area is in solstice occurrences of irregularities during high solar activity that the irregularities in December solstice months develop easier in the west area but those in June solstice months develop easier in the east area.     

柳珊瑚分子系统发育学的研究进展

珊瑚分子系统发育学研究始于90年代初,用于柳珊瑚分子系统学研究的主要分子标记是线粒体DNA和核糖体RNA。本文在重点介绍了柳珊瑚种群遗传多样性和柳珊瑚种上阶元系统发育学两方面的研究进展和所取得研究成果的同时,也讨论了珊瑚虫纲的系统发生关系。最后在简单引述了柳珊瑚分子系统发育学同传统形态分类学方法之间关系的同时,也对柳珊瑚分子系统发育学今后的重点研究方向做了预测。     

凡纳对虾引进亲本及其子代RFLP分析

运用 PCR-RFLP 技术分析凡纳对虾两个引进亲本群体及其各自子一代的遗传变异情况。用一对引物对这四个群体进行 mt DNA-细胞色素氧化酶I部分片段的 PCR 扩增,扩增结果为一条约 1.25 kb的条带。用 19种限制性内切酶对该扩增条带进行酶切分析,其中 Hinf I, Sty I, Taq I 这 种酶有酶切位点。用这3种 3酶进行限制性片段长度多态性 ( RFLP )分析,共获得 种限制性类型 基因型 。而且内切酶 2 ( ) Sty I在两个不同的引进亲本群体及其各自的子一代的扩增产物的酶切中,表现出明显的差异。     

中、低纬度地区电离层不同层结间的耦合对夜晚F区不规则结构的影响

电离层不规则结构的形成和演化与电离层等离子体不稳定性密切相关 .长期以来 ,在中低纬区扩展 -F现象的研究中 ,没有考虑电离层上下层结之间的相互作用 .本文从理论上全面探讨了在中纬度地区 ,E区可变的Pedersen电导率和Hall电导率 ,与F区可变的Pedersen电导率的共同作用对F区梯度漂移不稳定性的影响 ,导出了存在这种耦合时电离层梯度漂移不稳定性的统一表达式 .这一耦合理论不但解释了实际观测中发现的 ,在某些地方电离层F区顶部的不稳定性发生率要高于F区底部这一现象 ;同时还表明 ,电离层E区与F区的耦合对F区夜晚梯度漂移不稳定性的形成不仅会有阻碍作用 ,同时还使得中、低纬度地区的扰动增长具有了方向的选择性 .该理论的一个重要结论是 ,F区中某一地区能否发展出梯度漂移不稳定性 ,并不完全由当地电离层F区的状态决定 ,同一根磁力线连接的、位于不同纬度地区的E区层结对其发展和演化也会有相当大的影响 .     

等温剩磁各向异性及其在磁倾角校正中的应用

等温剩磁各向异性是一种新的磁组构研究方法 .与非滞后剩磁各向异性的参数一样 ,等温剩磁各向异性的参数直接与岩石中的携磁矿物颗粒形状有关 ,它直接反映了岩石形成与压实作用下携磁矿物的变形和变位 .利用等温剩磁各向异性技术 ,有可能对磁倾角偏低进行有效的校正 .本文介绍了等温剩磁各向异性及其在磁倾角校正中的应用 ,并以塔里木盆地库车拗陷的苏维依组红色砂岩的实验为实例 ,获得磁倾角校正值 ,与理想的欧亚板块磁倾角值十分吻合     

460铀-钼矿床控矿因素及矿床成因探讨

460矿床是上世纪80年代在冀北沽源中生代火山断陷盆地西部发现的大型铀-钼矿床。在对该矿床野外实地调研的基础上，结合矿床地质详查和矿床专题科研报告的综合分析，对矿床的控矿因素进行了系统总结。研究结果表明，矿床受NE向断裂（F45）和火山构造的联合控制；火山活动晚期沿断裂和中心式火山机构侵入的次流纹斑岩体是矿床定位的决定性因素；铀-钼矿化主要产于次流纹斑岩体产状变异部位或接触带附近；容矿构造为次流纹斑岩体接触带构造、隐爆角砾岩和J3z^3-5川层流纹岩中的层间裂隙带。研究认为，铀矿化受断裂构造、火山机构、岩浆活动、热液蚀变等作用的复合控制，其中火山口-火山通道相的次流纹斑岩体是主要的控矿因素。