Mangrove sediments were sampled form 14 main mangrove reserves of China. Concentrations of Cu, Pb, Zn, Cr and Cd were analyzed with a PE ICP-MS, and physical and physicochemical factors such as particle size distribut...Mangrove sediments were sampled form 14 main mangrove reserves of China. Concentrations of Cu, Pb, Zn, Cr and Cd were analyzed with a PE ICP-MS, and physical and physicochemical factors such as particle size distribution, pH, salinity and Total Organic Matter （TOM） were also determined. In the mangrove sediments of China, the average contents of heavy metals decreased in the order ofZn 〉 Pb 〉 Cu 〉 Cr 〉 Cd. The average contents of heavy metals were： Cu = 22.8 4- 16.46 mg/kg, Pb = 76.1 4- 52.33 mg/kg, Zn = 86.3 4- 42.65 mg/kg, Cr = 18.4 4- 5.83 mg/kg and Cd = 0.21 4- 0.25 mg/kg. Compared with previous studies, levels of heavy metals increased greatly. Contents of Cd, Cu, Pb and Zn were higher than the Background Values （BV）. However, the contents of Cr was under the BV. The results revealed that levels of heavy metals changes significantly with anthropogenic input, physical and physicochemical factors. Significant correlations were found between concentrations of Cu, Ph and pH, TOM.展开更多
The wave diffraction and radiation around a floating body is considered within the framework of the linear potential theory in a fairly perfect fluid. The fluid domain extended infinitely in the horizontal directions ...The wave diffraction and radiation around a floating body is considered within the framework of the linear potential theory in a fairly perfect fluid. The fluid domain extended infinitely in the horizontal directions but is limited by the sea bed, the body hull, and the part of the free surface excluding the body waterplane, and is subdivided into two subdomains according to the body geometry. The two subdomains are connected by a control surface in fluid. In each subdomain, the velocity potential is described by using the usual boundary integral representation involving Green functions. The boundary integral equations are then established by satisfying the boundary conditions and the continuous condition of the potential and the normal derivation across the control surface. This multi-domain boundary element method （MDBEM） is particularly interesting for bodies with a hull form including moonpools to which the usual BEM presents singularities and slow convergence of numerical results. The application of the MDBEM to study the resonant motion of a water column in moonpools shows that the MDBEM provides an efficient and reliable prediction method.展开更多
基金This project is supported by National Natural Science Foundation of China （No. 41176090）.
文摘Mangrove sediments were sampled form 14 main mangrove reserves of China. Concentrations of Cu, Pb, Zn, Cr and Cd were analyzed with a PE ICP-MS, and physical and physicochemical factors such as particle size distribution, pH, salinity and Total Organic Matter （TOM） were also determined. In the mangrove sediments of China, the average contents of heavy metals decreased in the order ofZn 〉 Pb 〉 Cu 〉 Cr 〉 Cd. The average contents of heavy metals were： Cu = 22.8 4- 16.46 mg/kg, Pb = 76.1 4- 52.33 mg/kg, Zn = 86.3 4- 42.65 mg/kg, Cr = 18.4 4- 5.83 mg/kg and Cd = 0.21 4- 0.25 mg/kg. Compared with previous studies, levels of heavy metals increased greatly. Contents of Cd, Cu, Pb and Zn were higher than the Background Values （BV）. However, the contents of Cr was under the BV. The results revealed that levels of heavy metals changes significantly with anthropogenic input, physical and physicochemical factors. Significant correlations were found between concentrations of Cu, Ph and pH, TOM.
文摘The wave diffraction and radiation around a floating body is considered within the framework of the linear potential theory in a fairly perfect fluid. The fluid domain extended infinitely in the horizontal directions but is limited by the sea bed, the body hull, and the part of the free surface excluding the body waterplane, and is subdivided into two subdomains according to the body geometry. The two subdomains are connected by a control surface in fluid. In each subdomain, the velocity potential is described by using the usual boundary integral representation involving Green functions. The boundary integral equations are then established by satisfying the boundary conditions and the continuous condition of the potential and the normal derivation across the control surface. This multi-domain boundary element method （MDBEM） is particularly interesting for bodies with a hull form including moonpools to which the usual BEM presents singularities and slow convergence of numerical results. The application of the MDBEM to study the resonant motion of a water column in moonpools shows that the MDBEM provides an efficient and reliable prediction method.
