The evolution of rifting on the volcanic margin of the Pelotas Basin and the contextualization of the Paraná–Etendeka LIP in the separation of Gondwana in the South Atlantic

The Pelotas Basin is the classical example of a volcanic passive margin displaying large wedges of seaward-dipping reflectors (SDR). The SDR fill entirely its rifts throughout the basin, characterizing the abundant syn-rift magmatism (133–113 Ma). The Paraná–Etendeka Large Igneous Province (LIP), adjacent to west, constituted the pre-rift magmatism (134–132 Ma). The interpretation of ultra-deep seismic lines showed a very different geology from the adjacent Santos, Campos and Espírito Santo Basins, which constitute examples of magma-poor passive margins. Besides displaying rifts totally filled by volcanic rocks, diverse continental crustal domains were defined in the Pelotas Basin, such as an outer domain, probably constituted by highly stretched and permeated continental igneous crust, and a highly reflective lower crust probably reflecting underplating.The analysis of rifting in this portion of the South Atlantic is based on seismic interpretation and on the distribution of regional linear magnetic anomalies. The lateral accretion of SDR to the east towards the future site of the breakup and the temporal relationship between their rift and sag geometries allows the reconstitution of the evolution of rifting in the basin. Breakup propagated from south to north in three stages (130–127.5; 127.5–125; 125–113 Ma) physically separated by oceanic fracture zones (FZ). The width of the stretched, thinned and heavily intruded continental crust also showed a three-stage increase in the same direction and at the same FZ. Consequently, the Continental-Oceanic Boundary (COB) shows three marked shifts, from west to east, from south to north, resulting into rift to margin segmentation. Rifting also propagated from west to east, in the direction of the final breakup, in each of the three segments defined. The importance of the Paraná–Etendeka LIP upon the overall history of rupturing and breakup of Western Gondwanaland seems to have been restricted in time and in space only to the Pelotas Basin.     

Vondrak滤波方法在软件接收机卫星双向时间传递中的应用

基于软件接收机的卫星双向时间传递(Two-Way Satellite Time and Frequency Transfer based on Software Defined Receiver, SDR-TWSTFT)链路每秒采集测量数据后通过数学模型将原始数据拟合为300 s一组的观测文件,因此链路的时间传递结果受短期测量噪声和非模型误差的影响,呈现出一定的随机噪声的特征.提出了一种频域幅值分析方法,针对性地确定滤波因子,构造符合需求的低通Vondrak滤波器.通过对中国科学院国家授时中心(National Time Service Center, NTSC)和德国联邦物理技术研究所(Physikalisch-Technische Bundesanstalt, PTB)之间的SDR-TWSTFT链路测量数据的分析发现,该方法对过滤链路平均时间一天内的高频噪声有效,能够提高链路时间传递结果的可信度,同时滤波后链路的短期频率、时间稳定度也有了显著提高.     

地震火山地层学及其在我国火山岩盆地中的应用

火山地层,物源来自于地下,搬运和分散方式有岩浆流、碎屑流、空落堆积及它们的再搬运,是不同于所有沉积地层的"异化地层".与层序地层学研究沉积地层类似,火山地层学着重研究火山岩系的层序界面和内部充填样式,通过地震层序分析刻画成因地层单元和地层对比关系.应用地震火山地层学在南海北部陆缘带识别出向海倾斜反射(SDR)、向陆流、...     

Application of partial least squares regression and WetSpa model to determine factors controlling sediment yield in Chardavol watershed,Iran

This paper examines the effects of watershed complexity in terms of physiography and land use on the specific sediment yield of the Chardavol watershed (1012.946 km²) in Iran. First, specific sediment yield was simulated using spatially distributed hydrological WetSpa model, then the influential factors such as morphometric variables, land-use composition and pattern and soil properties of the watershed were calculated at the sub-watershed scale. Due to the inter-reliant of these watershed characteristics, a partial least squares regression (PLSR) was used to illustrate the relationship between the specific sediment yield and data of 15 selected watershed characteristics. The results showed that the land-use composition and soil properties had the maximum effects on the specific sediment yield and clarified 79% of the variation in the specific sediment yield. Regarding the availability of digital spatial database over the watershed, this simple PLSR procedure could be applied in different watersheds.     

基于软件无线电的802.11 a OFDM系统实现

介绍4G移动通信系统的关键技术OFDM（正交频分多路复用）和软件无线电的基本概念,给出了OFDM系统模型,参照802．11a物理层的规范给出了OFDM符号帧结构。基于软件无线电的思想构建了OFDM传输系统。并用SystemView对OFDM传输系统的性能进行了仿真。     

基于SDR的GNSS接收机原理可视化教学平台

针对GNSS原理教学中,GNSS接收机原理部分缺乏直观的教学演示,提出了一种基于SDR的GNSS接收机原理可视化教学平台。通过这个平台,将封闭在硬件中的GNSS接收机实现方法直观地展现给学生,使学生加深了对GNSS接收机原理的认识。     

地震火山地层学研究综述

上个世纪60年代开始的深海钻探计划与其后的大洋钻探计划掀起了海洋研究的热潮。而研究被动大陆边缘,进而研究大陆张裂及至海底扩张的过程一直是这些计划的核心内容。挪威奥斯陆大学的Sverre Planke教授等在研究火山裂谷边缘时,提出了地震火山地层学的概念,用于分析火山沉积在地震上的响应。研究方法主要集中在对火山地震相单元的识别与描绘,并用火山岩知识对这些相单元进行解释。经过数年对大西洋沿岸和西澳大利亚裂谷边缘的地震反射数据的研究,Sverre Planke等先后识别出16种典型的火山岩地震相单元,本文选取其中8种研究得较为成熟的地震相单元来阐述地震火山地层学,分别为:近端向海倾斜反射体,②远端向海倾斜反射体,③外部隆起,④向陆熔岩流,⑤熔岩三角洲,⑥内部熔岩流,⑦穹隆,⑧岩席侵入。地震火山地层学为我们了解火山型裂谷边缘,分析该区大型火成岩省的形成过程提供了重要的技术和方法。     

GNSS软件无线电接收机及典型案例

介绍了GNSS软件无线电接收机和它与传统接收机相比的优缺点，并引述了典型的GNSS软件接收机及其应用。