Search

To investigating the influence of faulting on blast vibration wave propagation in an underground metal mine in Yunnan, the measuring points are arranged in the north and middle part of 3736 and the south and middle part of 3736 respectively. Using as a research object the actual blast vibration data collected from an underground metal mine in Yunnan, based on the wavelet packet transform, the HHT algorithm, and the STFT algorithm, the attenuation law of the blast vibration wave is investigated. The results show that the instantaneous energy amplitude of the vibration wave of a subsurface metal mine in Yunnan reaches 10X10-4 dB before the fault and 1. 5X10-4 dB after the fault, and the instantaneous amplitude of the energy attenuates by as much as 85%. This fault will perturb the energy distribution of the vibration wave to some degree and retard the rapid rise of the vibration energy. After the vibration wave passes through the fault, the low-frequency energy attenuates by 60%,the high frequency energy by 71%, the total energy power by 77%, the high frequency energy by 18%, the low frequency energy by 17%, and the overall energy power by 15%. Once the blast vibration wave has passed through the defect, a large amount of high-frequency energy is filtered out, and the overall energy distribution exhibits a trend toward the low-frequency domain. [ABSTRACT FROM AUTHOR]

Developing efficient and stable catalysts for synergistic removal of NOx and dioxin has always been key for controlling air pollution. For this, the hydrotalcite-like structured Cr(x)/LDO catalysts were successfully synthesized for synergistic removal of NOx and o-DCB using a co-precipitation method. The performance test results show that the Cr(0.25)/LDO catalyst has the best catalytic performance, and the NOx and o-DCB conversions are 89% and 82% at 250 °C, respectively. In addition, the reaction mechanism of NH3-SCR and o-DCB catalytic oxidation on the surface of the Cr(0.25)/LDO catalyst, and the interaction between the two reactions were investigated by designing in- situ DRIFTS experiments. The results indicate that the NH3-SCR reaction follows both E–R and L–H reaction mechanisms. The reaction pathway for the o-DCB oxidation process is proposed: o-DCB → chlorinated phenolate → benzoquinone → maleic acid, formic acid, acetic acid, etc. → H2O, CO2, HCl. Moreover, there are interactions between NH3-SCR and catalytic oxidation of o-DCB. At low temperature, there is obvious competitive adsorption between NH3/NO and o-DCB. The competitive adsorption between NH3/NO and o-DCB leads to the decrease of the o-DCB conversion. At high temperature, NH3-SCR and o-DCB oxidation exhibit a synergistic effect, NO2in situ-generated from the oxidation of NO can further participate in the o-DCB oxidation and reduce the accumulation of o-DCB oxidation intermediates on the catalyst surface. The research results contribute to understanding the reaction processes of Cr(x)/LDO catalysts and provide support for practical applications. [ABSTRACT FROM AUTHOR]