The life span of the data saved to a session is, at most, from the moment the user accesses a domain to the moment when a user times out after a preset amount of time of inactivity.

Based on the model of multi-span slender rod, the moment equations and deflection equations of elevator rail with duplex safety gear were established and resolved in a complex state of stress.

This paper has made use of the mo me nt distribution method to bring on the formulas of support moment of unequal span continuous beam less than or equal to four spans.