  We study the current-phase relation of the
superconductor/normal/superconductor (SNS) junction imbedded in a
superconducting loop. Considering the current conservation and free energy
minimum conditions, we obtain the persistent currents of the
normal/superconductor (NS) loop. At finite temperature we can explain the
experimentally observed highly non-sinusoidal currents which have maxima near
the zero external flux.
