It is caused by the property change of feed stock in storage process and alkadiene polymerization.

造成这一问题的主要原因，是原料油性质在存储过程中发生变化、二烯烃发生聚合。

It also put forward the connectible coefficient to simplify the description of the network, especially whose connection property changed frequently.

本文进一步提出利用路网连通系数表示路网连通性的方法，特别适于描述连通性变化较频繁的路网。