Based on some new concepts,the preceding main chain theorem,the succeeding main chain theorem and the total float theorem are offered,and then a method is given to find the second critical path in a CPM network quickly by total floats.

Node slack is of great importance in CPM network,and it is the most intuitive and the simplest for computing and applications in a variety of slacks.

At present,the study of the time-cost optimization is generally in the CPM network,and the traditional CPM network is not in line with the actual situation of the project.

Objective: To observe the effection of functional recovery of knee joint after total knee arthroplasty by the early rehabilitative functional training accompany with CPM,and discussing the method and the time of it after total knee arthroplasty.

Dyeing and printing machine synchronization system based on network and frequency conversion technologies;

Study and application of network derivation constraint method of multi-flow heat exchanger;

Study of network based CAI system for computer-aided calculation in chemical processes;