  We study X-ray spectra of four Narrow Line Seyfert 1 galaxies (NLS1s), Mrk
110, SWIFT J2127.4+5654, IGR J16185-5928, and WKK 4438, using Suzaku and NuSTAR
data. The spectra of the four sources are reproduced with a model consisting of
a cutoff power law component, a reflection component, and a soft excess
component. The photon indices of all the sources are found to be ~ 2. The
cutoff energies are constrained to be ~ 40 keV for Mrk 110, SWIFT J2127.4+5654,
and WKK 4438, whereas a lower limit of 155 keV is obtained for IGR J16185-5928.
We find that the NLS1s in our sample have systematically softer spectra and
lower cutoff energies than Broad Line Seyfert 1 galaxies reported in the
literature. We also perform spectral fittings with a model in which the cutoff
power law is replaced with the thermal Comptonization model in order to
directly obtain the electron temperature of the corona (kTe). The fits give kTe
~ 10-20 keV for Mrk 110 and SWIFT J2127.4+5654, and lower limits of kTe > 18
keV for IGR J16185-5928 and kTe > 5 keV for WKK 4438. We divide the NuSTAR data
of SWIFT J2127.4+5654 into three periods according to the flux. The spectral
fits in the three periods hint that kTe is the lower in the higher flux period.
The results of the four sources suggest a possible anti-correlation between kTe
and the ratio of the luminosity of Compton up-scattered photons to the
Eddington luminosity. The anti-correlation can be explained by a simple model
in which electrons in the corona are cooled and heated through inverse Compton
scattering and Coulomb collisions with protons, respectively.
