江西冷水坑银铅锌矿田闪锌矿铷-锶测年及地质意义

江西冷水坑矿田是武夷山地区重要的银铅锌集中区之一.无论其是世界上少有的斑岩型银铅锌矿床还是火山沉积-热液改造型矿床都独具特色,具有很高的研究价值.冷水坑矿田含矿斑岩的锆石年龄为162～155Ma,可作为花岗斑岩侵入的时间,绢云母Ar-Ar年龄与含矿斑岩活动时间的一致性说明冷水坑早期成矿发生于斑岩成岩过程中.本文首次采用闪锌矿Rb-Sr同位素测年方法获得冷水坑矿田成矿年龄为126.9±7.1 Ma,代表了冷水坑矿田晚期阶段矿化的年龄.冷水坑Ag-Pb-Zn矿田中大型—超大型矿床的形成,不但受中国东部燕山期构造体制转换的制约,而且受长期多阶段矿化的影响.     

浅海声速剖面自动分类方法研究

海洋中的声速剖面是影响水声设备效能的重要环境因素之一,声速剖面的自动分类和区划对海洋环境的应用意义重大.依据浅海30分方区按月统计声速剖面,通过归一化处理和Akima差值采样,建立了各方区按月归化后声速剖面的分层梯度样本集,并应用多种系统聚类算法分别对分层梯度样本集进行分析;计算各种算法在不同聚类数水平下聚类结果的总的类内离差和,依据总的类内离差和变化曲线拐点对应的聚类数目,结合分类结果确定浅海声速剖面最优聚类数目.对大量历史统计声速剖面数据的分析结果表明,该方法得到的聚类结果与人工经验分类结果吻合较好.     

基于TerraSuite的网络化三维空间信息平台的构建

介绍了基于TerraSuite的三维影像平台,分析了结合TerraSuite与ArcGIS软件实现网络化三维平台的可行性,构建了基于TerraSuite与ArcGIS的网络化三维空间信息平台。     

水声环境仿真及其可视化技术研究

针对水声环境对舰艇声纳探测效能的显著影响以及主要海域海洋环境特点,建立了浅海和深海水声环境仿真模型,实现了对海区水声环境的快速、准确预报。提出了基于3维声场纹理预积分的水声环境体可视化方法,实现了对水下声场的直观表达与多维分析,从而为水声环境的认知、教学训练以及决策支持提供了有效手段。     

水声环境仿真及其可视化技术研究

针对水声环境对舰艇声纳探测效能的显著影响以及主要海域海洋环境特点,建立了浅海和深海水声环境仿真模型,实现了对海区水声环境的快速、准确预报.提出了基于3维声场纹理预积分的水声环境体可视化方法,实现了对水下声场的直观表达与多维分析,从而为水声环境的认知、教学训练以及决策支持提供了有效手段.     

The dwarf low surface brightness galaxy population of the Virgo Cluster – II. Colours and H i line observations

In order to investigate the nature of dwarf low surface brightness (LSB) galaxies we have undertaken a deep B - and I -band CCD survey of a 14-deg² strip in the Virgo Cluster and applied a Fourier convolution technique to explore its dwarf galaxy population down to a central surface brightness of ∼26 B mag arcsec⁻² and a total absolute B mag of  ∼−10  . In this paper we carry out an analysis of their morphology, ( B − I ) colours and atomic hydrogen content. We compare these properties with those of dwarf galaxies in other environments to try and assess how the cluster environment has influenced their evolution. Field dwarfs are generally of a more irregular morphology, are bluer and contain relatively more gas. We assess the importance that various physical processes have on the evolution of cluster dwarf galaxies (ram-pressure stripping, tidal interactions, supernova-driven gas loss). We suggest that enhanced star formation triggered by tidal interactions is the major reason for the very different general properties of cluster dwarfs: they have undergone accelerated evolution.     

A revaluation of the Co/Ni ratio in pyrite as geochemical tool in ore genesis problems

On the basis of a sound evaluation of literature's data, the Co/Ni ratio in pyrite proves a more reliable indicator in ore genesis than previously retained. This is particularly true for volcanogenic pyritic ores which are constantly characterized by Co/Ni values (>5 but more often >10) definitely higher than those attained by sedimentary or hydrothermal pyrites. Moreover, once stated that an appropriate sampling has been performed, such geochemical studies, extended to as many deposits as possible from a same area, may provide relevant insights into the metallogenic history of the given area. On the basis of their Co/Ni ratios the Southern Tuscany ores fit in a two-stage metallogenic model: a primary (Paleozoic) emplacement of volcanogenic massive-sulfide deposits, in a sub-marine volcanic-exhalative environment, followed by later (Mio-Pliocenic) deposition of smaller, prevalently replacement deposits through hydrothermal partial mobilization of the older ones. The research of new ores may benefit from these geochemical studies too.