Hi Yu,
I would first advise bookmarking and using the mailing list archives in the future ?C this particular question has been asked and answered many times.
Attached is one such thread for your convenience ;).
Briefly, users of eQuest simply define slab materials/properties to match the prescribed F-factor, as defined in 90.1 Appendix A.
~Nick
NICK CATON, P.E.
