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In this paper, the formation process of single cathode spot on hydrogen titanium cathode is simulated. The influence of impregnation degree α(H content per metal atom) on the formation and development of craters was studied by the control variable method. In this model, hydrogen diffusion in the cathode is calculated, and the deformation of cathode metal is simulated by hydrodynamic model. The components considered in the model include electrons, titanium atoms, H atoms, Ti ions (Ti+, Ti2+ and Ti3+) and H+ ions. The simulation results show that the impregnation degree has a great effect on the cathode spot process. The average charge state on the pure titanium cathode is larger, while the total ion number density on the hydrogen titanium cathode is larger because of the extra hydrogen ions. Low impregnation hydrogen (impregnation degree less than 1) can reduce the surface temperature and ablation of the cathode. With the increase of impregnation degree, the proportion of titanium ions in the plasma cloud decreases gradually, resulting in the decrease of the total energy current density and the decrease of the radius and depth of cathode spots. The simulation results are broadly consistent with the work of other researchers.

The marine environmental conditions of typhoon affected area in South China Sea (SCS) in China are complicated. The parameters of wind, wave and current speed of different return period are the basis of the selection of oilfield project and the important role of development cost evaluation. Based on the deduction method of API specification, the design criteria of the typhoon in SCS oil and gas regions with the two-layer nested model combined with typhoon numerical model is proposed in this paper. The statistical analysis of typhoon characteristics were presented, then wind speed of all the blocks in north part of SCS induced by typhoon with long return period was calculated. The prediction accuracy of the design parameters of long return period is improved by this model.