Current density low, sedimentary speed is slow, prone to Yin and Yang, the luster of the poor, face Current density too high, convex department easily burnt.

The quality is a burnt magnesia spinel brick made from fused magnesia, low iron sintered magnesia and fused hercynite. This synthetic hercynite is a patent by RHI Refractories.

Quasi homogeneous charge compression ignition (QHCCI) combustion may be with low emissions, especially for soot and NO_X, according as the most fuel which is pre-mixed is lean burnt.