The comple mentary sink angle a and these maths models can be used to analyse the order and the balance condition of pressure on the soft rock coal mine laneway, so an accurate choice of support intensity can be chosen.

Analysis on the phase balance conditions and the chemical trend of certain element’s non-existence in a phase;

To meet the needs of the two balance conditions of both argument and amplitude simultaneously, at least, two parameters should be adjusted.

When the oscillation is stabilized, the oscillatory balance condition should be abided.

The result showed that,if only the necessary but insufficient condition,the equilibrium condition,was adopted to deal with the infinite uncertain boundary condition,the solution to the stress was non-unique due to the fact that the boundary problem here was a mal posed mathematic problem.

Using limit equilibrium condition,the paper analyzed plastic limit of Ring slab with simple inside and fixed outside support.

In this paper, it is pointed out that the element analysis, developed by Gibson et al, of honeycomb structures with walls in uniform thickness under in-plane shear load does not satisfy equilibrium conditions.