H II region G340.294−00.193. The R_eff and 2R_eff of the H II region are indicated as solid and dashed white circles, respectively. The purple squares highlight the position of HMSCs. The red, yellow, and blue crosses represent AS, PA, and NA HMSCs, respectively. The corresponding v_lsr in km s⁻¹ is shown close to the mark. Number −43.0 is the v_lsr of H II region in km s⁻¹. The RGB image is constructed in the same method as Fig. 1. The white contours represent SUMSS 35 cm emission. The v_lsr of the H II region is taken from Hou & Gao (2014) and Anderson et al. (2014), see Sect. 4.1.