We performed observations of the HC3N (24–23, 17–16, 11–10, 8–7) lines towards a sample consisting of 19 Galactic massive star-forming regions with the Arizona Radio Observatory 12 m and Caltech Submillimeter Observatory 10.4 m telescopes. HC3N (24–23, 17–16, 11–10, 8–7) lines were detected in sources except for W 44, where only HC3N (17–16, 11–10) were detected. Twelve of the nineteen sources showed probable line wing features. The excitation temperatures were estimated from the line ratio of HC3N (24–23) to HC3N (17–16) for 18 sources and are in the range 23– 57 K. The line widths of higher-J transitions are larger than lower-J ones for most sources. This indicates that the inner dense warm regions have more violent turbulence or other motions (such as rotation) than outer regions in these sources. A possible cutoff tendency was found around LIR ∼ 106 L⊙ in the relation between LIR and full width at half maximum line widths.
Considering the characteristics of narrow underground space and energy distribution, based on blade element momentum theory, Wilson optimization model and MATLAB programming calculation results, the torsion angle and chord length of wind turbine blade under the optimized conditions were obtained. Through coordinate transformation, the data were transformed into three-dimensional form. The three-dimensional model of the blade was constructed, and the horizontal axis wind turbine blade under the underground low wind speed environment was designed. The static structural analysis and modal analysis were carried out. Structural design, optimization calculation and aerodynamic analysis were carried out for three kinds of air ducts: external convex, internal concave and linear. The results show that the velocity distribution in the throat of linear air duct is relatively uniform and the growth rate is large, so it should be preferred. When the tunnel wind speed is 4.3 m/s and the rated speed is 224 rad/s, the maximum displacement of the blade is in the blade tip area and the maximum stress is at the blade root, which is not easy to resonate. The change rate of displacement, stress and strain of blade is positively correlated with speed. The energy of blade vibration is mainly concentrated in the swing vibration of the first and second modes. With the increase in vibration mode order, the amplitude and shape of the blade gradually transition to the coupling vibration of swing, swing and torsion. The stress and strain of the blade are lower than the allowable stress and strain of glass fiber reinforced plastics (FRP), and resonance is not easy to occur in the first two steps. The blade is generally safe and meets the design requirements.
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