基于模糊层次分析-多级可拓的北极东北航线不同航段风险评价

北南东北航线经度跨度大,海区地理环境复杂,其不同航段的通航环境在自然环境和人为干预的影响下,存在较大的差异性.不同航段的差异性分析对保障航行安全具有重要意义.结合模糊层次分析法(Fuzzy Analytic Hierarchy Process,FAHP)和多级可拓理论,基于构建的北南东北航线风险评价指标体系,对北南东北...     

酸洗法测定海洋沉积物有机碳和无机碳含量的致命缺陷

Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.