The Greek philosophers were obsessed with the chain of causality, how the cause of an effect should be traced back in a relay of hops until one reached the Prime Cause.
希腊哲学家痴迷于链式的因果关系，研究如何沿因果链条溯本追源，直至找到最初原因。
2
Compare with the traditional control with the relay, the PLC control lowers the practice cost, enhances the teaching effect, and increases the study efficiency.
与传统的继电器控制比较，PLC控制降低了实习成本，增强了教学效果，提高了学习效率。
3
The new type DC solid state relay is a kind of new contactless switching device, with the new type IGBT and power field effect tube as the core and composed completely by solid state electron devices.