  Using the generalized tortoise coordinate transformations the quantum
radiation properties of Klein-Gordon scalar particles, Maxwell's
electromagnetic field equations and Dirac equations are investigated in general
non-stationary black hole. The locations of the event horizon and the Hawking
temperature depend on both time and angles. A new extra coupling effect is
observed in the thermal radiation spectrum of Maxwell's equations and Dirac
equations which is absent in the thermal radiation spectrum of scalar
particles. We also observe that the chemical potential derived from scalar
particles is equal to the highest energy of the negative energy state of the
scalar particle in the non-thermal radiation in general non-stationary black
hole. Applying generalized tortoise coordinate transformation a constant term
$\xi$ is produced in the expression of thermal radiation in general
non-stationary black hole. It indicates that generalized tortoise coordinate
transformation is more accurate and reliable in the study of thermal radiation
of black hole.
