Time Domain Analysis on the Dynamic Response of a Flexible Floating Structure to Waves

A time-domain numerical method is developed to analyze the hydroelastic responses of flexible floating structures to waves; in which, the boundary element method is applied to evaluate the fluid motion and the finite-element method to analyze the elastic deformation of structure. The dynamic wave-structure interaction is simulated by prescribing the conditions on a wave generation boundary for each time step and by satisfying the continuity of the pressure and displacement on the fluid-structure interface. A time-domain solution is obtained in a predictor-corrector scheme and through a time-stepping computation. The effect of space and time discretizations on the convergence and stability of solution for regular, random and solitary waves is discussed by comparing among numerical solutions. The validity of the present method is verified by comparing it with the experimental results for the three kinds of waves mentioned. Further, the fission of a solitary wave under a flexible floating structure is observed both in numerical analysis and experiments.     

Three-Dimensional Indirect Boundary Element Method Formulation for Dynamic Analysis of Frames Buried in Semiinfinite Elastic Media

This paper presents a formulation of the indirect boundary element method based on the principle of virtual work for the dynamic analysis of frame structures buried in semi-infinite elastic media. The present formulation, which falls in the category of symmetric Galerkin boundary element methods, leads to symmetric stiffness matrices for the continuum that may be defined in terms of conventional structural analysis variables (i.e., generalized displacements and lumped forces). It is shown that, in the context of the present formulation, rotation degrees of freedom may readily be introduced in the interpolation scheme with very little additional computational effort. The consistency of the present formulation with well-established results is assessed by comparing the predictions for the static and dynamic stiffness of single piles with other results from the literature. Finally, the dynamic stiffness of a single buried frame under vertical and horizontal loading is studied. The analysis shows that the stiffness of the full frame may not always be accurately estimated by means of results for single piles, even when dynamic interaction factors are used.     

江西省钢铁领域科技发展的现状与未来

简要回顾了江西钢铁工业科技进步的历程和科技工作者的历史贡献，指出了当前江西省钢铁领域科技进步工作中值得重视的几个制约因素，在分析科技发展现状与趋势的基础上，提出了江西省钢铁领域中长期科技进步工作的战略目标、重点任务及其保障措施。     

在电解二氧化锰生产中去除硫酸锰溶液中As、Sb、Mo等离子的方法

用于碱性锌锰干电池正极活性材料的电解二氧化锰，其化学成分中的As、Sb、Mo杂质含量为0.000 0005％(0．5ppm)以下。因此，必须在电解二氧化锰的制备电解液——硫酸锰溶液阶段，去除溶液中的大量有害杂质。对于溶液中的As、Sb、Mo来说，应达到0．00000003％(0.03ppm)左右，方能保证电解电沉积的EMD中，达到0．0000005％(0．5ppm)以下。     

Extraction of Zinc‐Cobalt from Sulphate Solution of Cobalt Cake by D2EHPA in the Processing of Indian Ocean Nodules

During the processing of Indian ocean nodules, cobalt cake containing zinc in equal proportion is produced. In order to get pure cobalt and zinc from the sulphate leach solution of cake, a solvent extraction process has been considered using an organic extractant, di‐(2‐ethylhexyl) phosphoric acid (D2EHPA). Separation of cobalt and zinc has been carried out by mixing aqueous and organic phases in a rectangular vessel and separating the phases after equilibration in a glass funnel. The analysis of the metal from the aqueous phase was made by atomic absorption spectrometer to compute the metal transfer. The extraction and separation studies carried out under the different operating conditions indicated favourable zinc extraction at the lower pH (~ 2) with partially saponified D2EHPA. The small amount of cobalt co‐extracted with zinc was scrubbed with dilute sulphuric acid. With completely saponified D2EHPA, a high degree of cobalt extraction (99.8%) was achieved at aqueous feed pH of 5.0. The flow sheet developed could be used for the selective extraction and separation of zinc and cobalt from the leach liquor of cobalt cake.