  In view of the question about the vortex glass theory of the freezing of
disordered vortex matter raised by recent experimental observations we
reinvestigate the critical scaling of high $T_c$ superconductors. We find that
dc current-voltage characteristic of mixed state superconductors has the
general form of extended power law which is based on the Ginzburg-Landau (GL)
functional in the similar way as the vortex glass theory. Isotherms simulated
from this nonlinear equation fit the experimental I-V data of Strachan et
al.[Phys.Rev.Lett. 87, 067007 (2001)]. The puzzling question of the derivative
plot for the I-V curves and the controversy surrounding the values of critical
exponents are also discussed.
