威德尔海的重磁场特征及其构造意义

威德尔海是南极洲最大的边缘海。通过搜集威德尔海的重磁资料、历史文献以及总结前人的相关研究成果,介绍了威德尔海的重磁场基本特征以及指示的构造意义。威德尔海最显著的重力特征是在威德尔海的中北部分布着以鲱骨式结构展布的一系列NW-SE向重力异常,其上可见一系列弧形、上凹的以E-W为主要方向的磁力异常。沿南极半岛陆架边缘的重力高一直可延伸到南侧海域,高值区与陆架平行,但是在磁异常上反映不明显。威德尔海原始海盆的形成约在150 Ma,并伴随南北向张裂,随后在140 Ma发生东西向扩张,到约120 Ma异常形成现代南极洲、非洲和南美洲板块的分布格局,鲱骨式结构异常脊也形成于该时期。     

基于原始观测值的单频精密单点定位算法

研究了一种基于GPS原始观测值的单频PPP算法。该算法通过增加电离层延迟先验信息、空间和时间约束的虚拟观测方程,将电离层延迟当作未知参数与其他定位参数一并进行估计来高效修正电离层延迟误差。通过使用全球178个IGS站1d的实测数据对本算法的收敛速度、定位精度和电离层VTEC的精度进行检验与分析。结果表明,该算法的收敛速度和稳定性均得到了改善,其静态单频单天PPP解的精度可达2~3cm、模拟动态单频单天PPP解的精度可达2~3dm,并且单频PPP与双频PPP提取的电离层总电子含量平均偏差小于5个TECU,可作为一种附属定位产品使用。     

通过卫星双向双频观测对电离层时延的测定

介绍了利用卫星双向双频(C波段)观测来测定电离层时延的方法,并对不同经纬度的观测结果进行了比较和分析。卫星双向双频(C波段)观测精度高,采样间隔短,能测定电离层总电子含量的细微变化。     

GPS掩星技术和电离层反演

系统地介绍了GPS无线电掩星技术的发展现状、系统组成和一些关键技术；论述了利用GPS掩星数据进行电离层反演的理论、模型及相应的计算流程．并结合GPS／MET和CHAMP卫星的实测资料，计算了电子密度剖面，与用其他方法所得结果的对比表明．GPS掩星电离层观测具有精度高、覆盖范围大等特点；最后讨论了GPS掩星技术应用于地震前兆监测的机理和前景。     

2-D or 3-D interpretation of conductivity anomalies: example of the Rhine-Graben conductivity anomaly

Summary. Evidence of a conductivity anomaly in the Rhine-Graben was first given about 15 years ago and consequently led to the definition of various models of induction in the region for periods ranging from a few minutes to a few hours. These models reflect two antagonistic ways of explaining the observed anomalous variations of the magnetic field: direct induction in a two-dimensional (2-D) structure or static distortion of telluric currents by the resistive crystalline Vosges (France) and Schwarzwalde (Germany) massifs. We discuss the two approaches using a simple formalism. In particular, we show that the self-induction related to the anomalous currents flowing in the Rhine-Graben is negligible for periods larger than 1000 s, and that, even though the static distortion of telluric currents does account for the observed anomaly, 2-D models can explain some of its features. We also show how the channelled currents are induced in the large sedimentary basins surrounding the area under study.
An experimental verification of this result is given.     

Propagation of Extremely Low Frequency Waves Through the Ionosphere

The propagation features of extremely low frequency electromagnetic waves through the multicomponent ionospheric plasma are studied. It is shown that at relatively lower frequencies refractive index for right hand mode is higher than the left-hand mode, which is reversed at higher frequencies. The thermal temperature of plasma particle causes decrease in phase and group velocities of both right and left-hand modes. The crossover frequencies for different plasma models are computed and variation with ion concentration and thermal velocity is studied. Explicit expression for group velocity and travel time has been derived and studied numerically. Finally, we have presented simulation of the ion whistler spectrograms for Hydrogen, Helium and Oxygen ions present in the ionospheric plasma. The results are compared with the experimentally detected hydrogen and helium ion whistlers. The importance of the present study in the exploration of ionospheric plasma is illustrated.     

Hydro simulations of the ICM: the effect of energy feedback

Current models and observations of variability in HgMn stars disagree.We present here the models that argue for pulsating HgMn stars with properties similar to those of SlowlyPulsating B Stars. The lack of observed variable HgMn stars suggeststhat some physical process is missing from the models. Somepossibilities are discussed.     

新疆精河莱历斯高尔铜钼矿床原生地球化学异常

矿区处于博罗霍洛山主脊,属斑岩型铜钼矿床。斑岩体本身为矿体,钼矿在岩体内,铜矿在外接触带。通过矿区北部勘查地球化学工作表明,Mo、Cu、Pb、Ag、As原生地球化学异常规模大、连续性好,形态规则,梯度大。As、Sb、Ag具前缘特征。除Mo、Cu外,Pb、Ag具主成矿元素特征。原生异常纵向分带具轴向分带特征,分带序列有一定的典型意义。从地质、地球化学异常特征、小岩体地球化学特征以及金属预测资源初步计算认为该矿床很有远景。