The 2-1 and 5-4 transitions of SiO have been observed toward the Sgr B2 region, including the Principal Cloud(the GMC containing Sgr B2(M)) and its surroundings. The morphology and velocity structure of the SiO emission show a close resemblance with the HNCO Ring feature, identified by Minh & Irvine(2006), of about 10 pc in diameter, which may be expanding and colliding with the Principal Cloud. Three SiO clumps have been found around the Ring, with total column densities Nsio ~1x1014 cm-2 at the peak positions of these clumps. The fractional SiO abundance relative to H2 has been estimated to be ~(0.5-1)X10-9, which is about two orders of magnitude larger than the quiet dense cloud values. Our SiO observational result supports the existence of an expanding ring, which may be triggering active star formations in the Principal Cloud.

The 3mm transitions to CO, 13CO, CS, HCO+, and HCN have been observed toward the compact HII regions in W58 using the 14m Daeduk Radio Telescope (DRT). Some of the observed lines show high-velocity wings resulted from outflowing materials of the compact HII regions. We derive the beam averaged column densities of the observed species and compare their relative abundances. The HCO+ abundance appears to be smaller by about an order of magnitude than those of 'typical' quiet molecular clouds. CS may be a good reference molecule in comparing relative abundances in different physical conditions.

Using the Daeduk Radio Telescope, we have observed J = 1 → 0 transitions of 1 12 C O , 13 C O a n d C 18 O toward OMC-l. The column densities of 1 \~ 5 × 10 17 c m − 2 a n d 1 \~ 3 × 10 16 c m − 2 have been derived, for 13 C O and C 18 O , respectively, in the 11 ′ × 11 ′ region centered at Orion - KL. The double isotope ratio [ 13 C O ] / [ C 18 O ] was found to be larger than the cosmic abundance ratio by factors of 2 \~ 10 which may result from the chemical fractionation effect.