The transformation from "the physical production" to "the living production"is a new observation on Marxs living source determinating peoples physical production.

The harmonic impedance on two sides of converters in HVDC transmission system is important in determinating the harmonics due to GIC (geomagnetic induced currents).

Stresses of the in-explosive cylinder were analyzed, compound criteria for determinating the fracture radius was put forward to calculate the initial velocity of cylinder fragment.