The influence of the gas space on the top of an integral reactor vessel on the flow stability in the start up process of a natural circulation two phase flow system is studied experimentally.

The phase difference caused by piston error translated with the tiled-grating compressor, the focal spot was affected by both non-integral number of grating space and out-of-plane piston error.

The integral invariant construction of holonomic nonconservative dynamical systems in the high-dimensional extended phase space;