  We assume that the gravitational instability of standard thin accretion disks
leads to the Broad Line Regions (BLRs), the B band luminosity comes from
standard thin disk and the motion of BLRs is virial. The central black hole
masses, the accretion rates and the disk inclinations to the line of sight for
17 Seyfert 1 galaxies and 17 Palomar-Green (PG) quasars have been calculated.
Our results are sensitive to $\alpha$ parameter of the standard $\alpha$ disk.
With the same values of $\alpha$ ($\alpha=1$), calculated central black hole
masses for 17 Seyfert 1 galaxies are consistent with that from Kaspi et al.
(2000) while that for 17 PG quasars are larger than that from Kaspi et al.
(2000) by almost 2 orders of magnitude. Inclinations of 17 Seyfert 1 galaxies
are about 6 times larger than that of 17 PG quasars. These inclinations, with a
mean value of $32^{o}$ for 17 Seyfert 1 galaxies that agrees well with the
result obtained by fitting the iron $K\alpha$ lines of Seyfert 1 galaxies
observed with ASCA (Nandra et al. 1997) and the result obtained by Wu & Han
(2001), provide further support for the orientation-dependent unification
scheme of active galactic nuclei. There is a relation between the FWHM of
H$\beta$ and the inclination, namely the inclination is smaller in AGNs with
smaller FWHM of H$\beta$. The effect of inclinations in narrow line Seyfert 1
galaxies (NLS1s) should be considered when one studies the physics of NLS1s.
(abbreviated)
