MED路由策略研究

边界网关协议是目前用于广域网中最主要的域间分布式动态路由协议,具有丰富的路由控制机制。MED属性的使用不当通常会引起热土豆路由和MED振荡。介绍热土豆路由和MED振荡,总结分析了避免热土豆路由和MED振荡的方法,并针对广域网和专网分别提出了整体的MED路由策略,最后利用仿真软件加以验证。     

郭山高岭土铁钛赋存状态的分析电子显微术研究

使用分析电子显微术对福建郭山高岭土中铁、钛元素的赋存状态进行了研究。结果表明,高岭土中铁钛的赋存状态分为两类,一类为参加到粘土矿物晶格中的铁和钛,简称为结构铁、结构钛;另一类为游离出现或吸附在高岭矿物(高岭石和埃洛石)颗粒表面的铁、钛矿物。查明了在全铁和全钛中,结构铁和结构钛仅占少数,大部分以铁、钛独立矿物形式出现。从而确定了可将高岭土粘粒级(<2μm)中铁、钛含量降低到的最低限度,这便为提高高岭土品级和经济价值提供了可靠的依据。     

The Effect of Temporal Changes and Environmental Trophic Condition on the Isotopic Composition (ω13C and ω15N) of Atherina boyeri (Risso, 1810) and Gobius niger (L., 1758) in a Mediterranean Coastal Lagoon (Lake of Sabaudia): Implications for Food Web Structure

Abstract. ω¹³C and ω¹⁵N of organic matter sources and consumers were employed to analyse trophic differentiation between a benthic consumer, Gobius niger (L., 1758) (Pisces, Osteichthyes), and a pelagic consumer, Atherina boyeri (Risso, 1810) (Pisces, Osteichthyes) in a Mediterranean coastal lagoon (Lake of Sabaudia) in winter and summer 1999. Trophic differences between the two species throughout the two sampling periods were related to the environmental trophic condition (i. e. nutrient and phytopigment concentrations). Although these two fish have different habitats, they both exploited benthic organisms, above all in summer. When the nutrient and phytopigment concentrations were higher (summer), the most abundant benthic organisms were the main food sources for both species. In winter A. boyeri apparently shifted its feeding preferences to include zooplankton, confirming its opportunistic feeding strategy. Par-ticulate organic matter and algae seemed to play the main trophic role in the food web structure. Benthic invertebrates used both sources, while zooplankton seemed to rely exclusively on the particulate fraction. The overlapping and very depleted signatures of sedimentary and particulate organic matter highlights a strong link between sediments and water column, rarely observed in other aquatic ecosystems using stable isotopes. Such a finding further substantiates the importance of particulate organic matter as a food source in the study area.     

基于MED的探地雷达信号处理研究

   文中运用改进的最小熵反褶积（MED） 理论,采用MATLAB编写程序,实现了改进的MED计算机自动处理功能。将 其应用到在建中的某地铁4号线某区间的探地雷达资料处理中,较准确地确定了岩溶的位置和尺寸。将处理结果与钻孔岩 芯资料进行比照,发现雷达探测结果与钻探结果具有较好的一致性,表明MED方法能在雷达剖面上有效显示溶洞位置,该 项研究成果对类似工程具有重要借鉴意义。