Using provision of centrally compressed lattice columns,the maximum slenderness-ratio of the T-shaped-cross-section component above the opening and the maximum width of opening are decided.

Under complicated geological conditions,large slenderness ratio ultra-deep well sinks in the ultra-soft soil by prevented sinking method,sinks in hard soil by assisted sinking method,and in the process of sinking to take difficult technical measures of anti-tilt,correcting,and prevent sudden sinking to make large slenderness ratio ultra-deep wells vertically and evenly sink in the position.

The relationship between N/P ratios and maximum specific growth rate of red tide algae was analyzed according to Shelford\'s law of tolerance to study the response mechanism between N/P ratios and red tide algae,and the tolerance model between specific growth rate of red tide algae and N/P ratios was established.

The batch respirometric method was applied for the determination of the concentrations and the maximum specific growth rate(μ^A) of autotrophic biomass (XA) in mixed liquors from aerobic tanks of a full-scale wastewater treatment plant with anaerobic/anoxic/aerobic process and a pilot-scale anaerobic/aerobic process.

Sensitivity analysis showed that the performance of activated sludge system was affected remarkably by heterotrophic decay rate, heterotrophic maximum specific growth rate and autotrophic maximum specific growth rate, so these parameters were studied.