Excessive plant height is an important factor that can lead to lodging, which is closely related to soybean yield. Gibberellins are widely used as plant growth regulators in agricultural production. Gibberellic acid (GA3), one of the most effective active gibberellins, has been used to regulate plant height and increase yields. The mechanism through which GA3 regulates internode elongation has been extensively investigated. In 2019 and 2020, we applied GA3 to the stems, leaves, and roots of two soybean cultivars, Heinong 48 (a high-stalk cultivar) and Henong 60 (a dwarf cultivar), and GA3 was also applied to plants whose apical meristem was removed or to girded plants to compare the internode length and stem GA3 content of soybean plants under different treatments. These results suggested that the application of GA3 to the stems, leaves, and roots of soybean increased the internode length and GA3 content in the stems. Application of GA3 decreased the proportion of the pith in the soybean stems and primary xylem while increasing the proportion of secondary xylem. The apical meristem is an important site of GA3 synthesis in soybean stems and is involved in the regulation of stem elongation. GA3 was shown to be transported acropetally through the xylem and laterally between the xylem and phloem in soybean stems. We conclude that the GA3 level in stems is an important factor affecting internode elongation.

This paper investigated the effectiveness of a vent burst door in isolating the shock waves of gas explosions in coal mines and to reveal the mechanisms of gas explosion overpressure. A 17.5 m × φ 0.63 m columnar explosion test duct with a similar shape to the roadways in coal mines was designed. Explosion overpressure propagation characteristics and the effects of methane concentration at different locations along the duct with and without a vent burst door were experimentally investigated. The results demonstrate that the vent burst door plays a significant role in sealing the explosion area and isolating the explosion propagation. A properly designed vent burst door is a promising technique for suppressing and isolating multiple and continuous gas explosions and is poised to have a significant positive impact on improving the safety of coal mines in China and all over the world.

Addressing the issue of suffocation and casualties caused by a large amount of poisonous CO gas generated after a gas explosion, research involving an experimental system for the removal of CO using a Cu−Mn elimination agent was studied. The influence of O 2 concentration, temperature, and CO concentration on the elimination performance of the agent after a gas explosion was studied. The quantitative relationship between the amount of CO eliminated, the elimination rate, the O 2 concentration, and temperature was analyzed. Further analysis was completed regarding the influence of O 2 concentration, temperature, and CO concentration on the thermal effect in the elimination process. The results showed that the elimination agent had a rapid effect on the removal of CO. When the ratio of CO concentration to O 2 concentration was closer to the stoichiometric ratio, the elimination and reaction were more complete, the time to complete elimination was shorter, and the peak temperature was higher. As the temperature increased, the time to reach the elimination limit became longer, the elimination rate decreased, the reaction was slower, and the peak temperature was lower. As the CO concentration increased, it was observed that the higher the peak temperature, the longer it took to reach the peak time. The results of the study provide a theoretical support for the catalytic oxidation of CO using the Cu−Mn eliminator after a coal mine gas explosion.