Black hole X-ray binaries (BHXBs) in our galaxy provide important clues to 
understand the fundamental physics of black hole accretion and outflows 
over a wide range of mass accretion rates. At high X-ray luminosities, they 
exhibit soft X-ray dominated spectra, which are well described by the 
standard disk model ("high/soft state"). In contrast, at low luminosities, 
the hard X-ray contribution to the entire flux becomes more substantial 
("low/hard state"). The hard X-ray emission is explained by unsaturated 
Compton up-scattering of disk emission by hot electrons. However, the 
physical properties and geometry of the electron cloud remain to be studied. 
In the high/soft state, highly ionized, blueshifted absorption lines 
originating in disk winds are often detected in high inclination BHXBs,
while they are rarely seen in low/hard state. It is still unclear whether 
the disk winds are present but almost completely ionized, 
or somehow suppressed in the low/hard state.

In this talk, I present the results from our recent Suzaku Time-Of-Opportunity 
observations of the Galactic black hole transients  H 1743-322 and 
MAXI J1305-704 in the low/hard state. The wide-band high-quality data 
enabled us to constrain the inner disk structure. I also report the discovery of 
ionized absorption in MAXI J1305-704 during the low/hard state and discuss 
its origin.