The author believes that the bearing core is a precondition for leap-frog penetration and for maintaining the constant angle offracture resulted from the release of the energy absorbed by the core.
认为承压核是造成跃进式侵入和破碎角稳定的条件，跃进式侵入和破碎角稳定是承压核储能释放的结果。
2
The causes offractureof the chipper knives made in China are analysed. A new process on gaseous Carbon-Nitrogen-Boron penetration is tested and better results have been achieved.
Popularity of acid emulsion treatment is duo to the fact that can be used in high temperature Wells and slow reaction rate which results in a deeper fracturepenetration.