Methane explosion suppression characteristics based on the NaHCO3/red-mud composite powders with core-shell structure.

The NaHCO3/red-mud (RM) composite powders were successfully prepared by the solvent-anti-solvent method for methane explosion suppression. The RM was used as a carrier, and the NaHCO3 was used as a loaded inhibitor. The NaHCO3/RM composite powders showed a special core-shell structure and excellent endothermic performance. The suppression properties of NaHCO3/RM composite for 9.5% CH4 explosion were tested in a 20L spherical explosion vessel and a 5L Perspex duct. The results showed that the NaHCO3/RM composite powders displayed a much better suppression property than the pure RM or NaHCO3 powders. The loading amount of NaHCO3 has an intensive influence on the inhibition property of NaHCO3/RM composite powders. The best loaded content of NaHCO3 is 35%. It exhibited significant inhibitory effect that the explosion max-pressure declined 44.9%, the max-pressure rise rate declined 96.3% and the pressure peak time delayed 366.7%, respectively.

Comparative study on specific chromatograms and main active components of wild and cultivated rhizomes of Paris polyphylla var. yunnanensis / 中国中药杂志

The present study is to compare specific chromatograms and main acitive components between wild and cultivated rhizomes of Paris polyphylla var. yunnanensis by HPLC. HPLC analysis was performed on a Waters XSelect HSS T3 C₁₈ clumn (4.6 mm×250 mm, 5 μm), with a mobile phase consisting of acetonitrile (A)-water (B) at a flow rate of 1 mL•min⁻¹ (0-50 min,30%-50%A;50-80 min,50% A,80-85 min,50%-30%A;85-100 min,30% A). The detection wavelength was 203 nm and the column temperature was controlled at 30 ℃, and the injection volume was 10 μL. HPLC specific chromatograms of wild and cultivated rhizomes of P. polyphylla var. yunnanensis were established and nine steroidal saponins were simultaneously determined by the above method. The mean contents of paris saponin Ⅶ, paris saponin H and total average contents of four pennogenyl saponins in Rhizomes of wild samples were significantly higher than those of cultivated ones. However, this result is opposite from the average content of paris saponin Ⅰ and total average contents of five dioscins in the wild and cultivated samples. Because the significant differences occurred for the specific chromatograms and main active components between the wild and cultivated P. polyphylla var. yunnanensis, much more pharmacological and clinical researches are therefore necessary.