We have revisited Monte Carlo radiative transfer calculations for clumpy molecular clouds. Instead of introducing a three-dimensional geometry to implement clumpy structure, we have made use of its stochastic properties in a one-dimensional geometry. Taking into account the reduction of spontaneous emission and optical depth due to clumpiness, we have derived the excitation conditions of clumpy clouds and compared them with those of three-dimensional calculations. We found that the proposed approach reproduces the excitation conditions in a way compatible to those from three-dimensional models, and reveals the dependencies of the excitation conditions on the size of clumps. When bulk motions are involved, the applicability of the approach is rather vague, but the one-dimensional approach can be an excellent proxy for more rigorous three-dimensional calculations.

In order to reduce the small scale fluctuation resulting from shearing holograpy(Park et. al. 1997), differential panel adjustments were performed for 14 m radio telescope of Taeduk Radio Astronomy Observatory with T2 theodolite It appears that this method improves the surface accuracy by about 50μm 50μm . The measured surface accuracy is, at best, 170μm 170μm . The beam efficiency at 86.2 GHz is estimated to be 44% We also found that the elevation at which Park et. al. performed holography was too low.

The HII region S140 and the associated molecular cloud L1204 have been observed with 10 molecular transitions, CO (1-0), 13CO (1-0), C18O (1-0), CS (2-1), HCO+ (1-0), HCN (1-0), SO (22-11), SO2(220-313), OCS (8-7), and HNCO (404-303) with ~ 50" angular resolutions. More than 7,000 spectra were obtained in total. The morphology of this region shows a massive fragment (the S140 core) and the extended envelope to the northeast. Several gas condensations have been identified in the envelope, having masses of ~103M⊙ and gas number densities of ≾104cm-3 to 3×105cm-3 in their cores. The column densities of the observed molecular species toward the S140 core appear to be the typical warm clouds' abundances. It seems to be that the S140 core and L1204 have been swept up by an expanding shell called the Cepheus bubble. The large value of LIR(embedded stars)/Mcloud ~5 L⊙/M⊙ of the S140 core may suggest that the star formation has been stimulated by the HII region, but the shock velocity and the pressure of the region seem to give a hint of the spontaneous star formation by the self gravity.