Areas of the global major river plumes

River plumes are the regions where the most intense river-sea-land interaction occurs, and they are characterized by complex material transport and biogeochemical processes. However, due to their highly dynamic nature, global river plume areas have not yet been determined for use in synthetic studies of global oceanography. Based on global climatological monthly averaged salinity data from the NOAA World Ocean Atlas 2009 (WOA09), and monthly averaged salinity contour maps of the East and South China Seas from the Chinese Marine Atlas, we extract the monthly plume areas of major global rivers using a geographic information system (GIS) technique. Only areas with salinities that are three salinity units lower than the average salinity in each ocean are counted. This conservative estimate shows that the minimum and maximum monthly values of the total plume area of the world’s 19 largest rivers are 1.72 × 10 6 km 2 in May and 5.38 × 10 6 km 2 in August. The annual mean area of these river plumes (3.72 × 10 6 km 2 ) takes up approximately 14.2% of the total continental shelves area worldwide (26.15 × 10 6 km 2 ). This paper also presents river plume areas for different oceans and latitude zones, and analyzes seasonal variations of the plume areas and their relationships with river discharge. These statistics describing the major global river plume areas can now provide the basic data for the various flux calculations in the marginal seas, and therefore will be of useful for many oceanographic studies.     

包裹缓释外壳的缓释氧材料的性能影响分析

针对地下水水质原位生物修复过程中由于缺乏氧气导致的生物活性降低、修复作用受抑等问题,以过氧化镁(MgO2)为释氧原料,塑性剂、缓冲剂、造孔剂为载体材料,采用共混滚动造粒技术,分别制备出包裹和不包裹缓释外壳的释氧材料(ORC)并进行材料性能对比分析。扫描电镜和静态实验研究表明:粒径在0.6～0.8 cm之间未添加缓释外壳的ORC材料,其机械强度约为14～18 N,固液比投加量2 g/L时,氧释放系数K为0.005 89,氧平衡浓度Cm为10.641 mg/L,材料在实验四个月后溶解氧含量达到峰值后开始逐渐下降;粒径在0.6～0.8 cm之间添加缓释外壳的ORC材料,其机械强度达到30～70 N,液固比投加量2g/L时,氧释放系数K为0.004 66,氧平衡浓度Cm为10.57 mg/L,八个月后溶解氧浓度开始逐渐下降。分析结果表明,添加缓释外壳的ORC材料其强度和释氧周期都有提高。     

地震作用下含弱面斜坡变形破坏实验研究

为了研究含弱面斜坡在强震作用下变形破坏规律,对含单一弱面的3组斜坡模型模拟地震作用下的变形破坏,并用数字散斑相关方法对实验结果进行处理,得到斜坡模型位移和应变。从实验结果可以发现:位移和应变变形均集中在弱面上,随着震动的持续,这种变形积累最终导致斜坡发生破坏; 模型对比中可以发现,在斜坡体内弱面越深则斜坡稳定性越强,在斜坡体内弱面越长则斜坡稳定性越弱。分析模型最初在顶部出现裂缝和沿弱面发生滑动的原因。     

道康宁推出新一代高性能建筑硅基材料

为了满足高性能建筑日益增长的需求,改进其总体能源管理、健康与安全性、耐久性并降低建筑的碳排放,在近日举办的第八届国际绿色建筑与建筑节能大会上,美国道康宁公司推出了新一代有机硅材料。     

“老马”带来的改变——浅谈MARIAN软件的应用和思考

本文着眼于惠生工程独山子项目工程材料管理和MARIAN推广应用实务,阐述了一个基于MARIAN数据库面向工程材料管理过程中的成败、分析、应用、关键控制以及前景展望,旨在为项目材料管理的未来实施去铺平道路,指明方向。     

The kilosecond variability of X-ray sources in nearby galaxies

Chandra observations of 17 nearby galaxies were analyzed and 166 bright sources with X-ray counts 〉 100 were chosen for temporal analysis. Fractional root mean square （rms） variability amplitudes were estimated for light curves, binned at 4 kilosecond （ks）, with length 〈 40 ks. While there are nine ultra-luminous X- ray sources （ULXs） with unabsorbed luminosity （in the 0.3-8.0 keV band） L 〉 1039 erg s-1 in the sample for which the fractional rms variability is constrained to be 〈 10%, only two of them show variability. One of the variable ULXs exhibits a secular transition and has an ultra-soft spectrum with temperature - 0.3 keV while the other is a rapidly varying source in NGC 0628, which has previously been com- pared to the Galactic microquasar GRS 1915＋105. These results seem to indicate that ULXs are typically not highly variable on ks timescales, except for some ultra-soft ones. Among the relatively low luminosity sources （L - 10^38 erg s-1）, we find five of them to be variable. Apart from an earlier known source in NGC 1569, we identify a source in NGC 2403 that exhibits persistent high amplitude fluctuations. In general, the variability of the sources does not seem to be correlated with hardness, which indicates that they may not be due to variations in any absorbing material, but instead could reflect instabilities in the inner accretion disk.     

《企业名称预先核准通知》能否作为取得采矿许可证的身份材料？

案情简介 2008年12月,在S市2008年第3期采矿权挂牌出让活动中,张某成为竞得人,随后与S市国土资源局签订了《采矿权挂牌公开出让成交确认书》和《采矿权出让合同》,合同约定由张某组建有资质的矿山企业从事矿产资源的开发。合同签订后,张某以个人名义缴纳了全额价款。     

在部机关司局和督察局领导班子对照检查材料点评会上的讲话

党的十八届三中全会刚刚胜利闭幕。今天,召开部机关司局、督察局领导班子对照检查材料点评会,是我部学习贯彻三中全会精神、深入扎实开展教育实践活动的一个重要步骤。这次会议的主要目的是,交流、点评各单位领导班子对照检查材料,查找差距,传导压力,拧紧螺丝,进一步把教育实践活动引向深入。     

基于数字图像的真实细观非均质岩土力学分析数值方法

本文介绍基于真实非均质岩土材料的数值方法与研究进展.这些方法运用新发展的数字图像技术,获取真实岩土和混凝土材料的细观非均质分布,再进行定量细观结构研究,采用数值计算程序,定量分析它们的物理力学响应,为解决限制岩土和混凝土力学进一步发展的非均质材料假设问题提供了有效途径.本文介绍该方法的研究背景和三项主要内容.包括真实细...     

动力荷载作用下混凝土破裂特征的CT试验研究

汶川地震后,强震作用下的大坝混凝土动态力学性能研究广受关注.本文利用CT技术对动力荷载作用下混凝土细观破裂过程进行实时扫描观测,获得了混凝土试件在动力荷载作用下裂纹的开裂、扩展、贯通的全过程CT图像,并给出了动力压缩、动力拉伸CT试验的初步成果.结果表明:动力压缩荷载条件下混凝土破坏时裂纹起裂点多,裂纹演化速度快,能够...