针对爆破振动信号具有非线性、随机性较强的特点,提出利用局部波分解(Local Mean Decomposition,LMD)处理并分析爆破振动信号。结合露天铁矿逐孔起爆方式下爆破振动测试信号分析,研究信号的时频及能量分布特征。结果表明:LMD方法能完整...针对爆破振动信号具有非线性、随机性较强的特点,提出利用局部波分解(Local Mean Decomposition,LMD)处理并分析爆破振动信号。结合露天铁矿逐孔起爆方式下爆破振动测试信号分析,研究信号的时频及能量分布特征。结果表明:LMD方法能完整地分解重构爆破信号,有效减少模态混叠现象,更加真实反映信号的原始信息;相比经验模态分解方法(Empirical Mode Decomposition,EMD)、LMID方法的端点效应轻微,具有较高的解凋精度;LMID方法可以精确分析振动能量的分布规律,有利于进一步识别爆破本身的力学作用特征。展开更多
The present paper covers an X-ray photoelectron spectroscopic (XPS) method proposed for identifying Bronsted and Lewis acidic sites in zeolites and estimating acidic strength of these sites. It was found that the adso...The present paper covers an X-ray photoelectron spectroscopic (XPS) method proposed for identifying Bronsted and Lewis acidic sites in zeolites and estimating acidic strength of these sites. It was found that the adsorption of pyridine on different acidic sites of H[M]-ZSM-5 zeolites exhibited three peaks: A (402.20-401.30 eV), B (400.95-400.40 eV) and C (399. 40-399. 10 eV). The peaks A and B are assigned to the N(?) level of pyridine adsorbed on Bronsted and Lewis acidic sites, and peak C is assigned to the N(?) level of pyridine adsorbed on a weak Lewis site and/or strongly physisorbed pyridine, respectively. The comparison of the ratio of the Bronsted and Lewis acidic sites determined from the relative intensities of the N(?), peaks with IR spectroscopic data shows that there is an inhomoge-neous distribution of Bronsted and Lewis acidic sites in H[M]-ZSM-5 zeolites. The N(?), binding energies of pyridine adsorbed on these zeolites directly reflect acidic strength, and these results are in good agreement with those observed in NH3-TPD experiments.展开更多
文摘针对爆破振动信号具有非线性、随机性较强的特点,提出利用局部波分解(Local Mean Decomposition,LMD)处理并分析爆破振动信号。结合露天铁矿逐孔起爆方式下爆破振动测试信号分析,研究信号的时频及能量分布特征。结果表明:LMD方法能完整地分解重构爆破信号,有效减少模态混叠现象,更加真实反映信号的原始信息;相比经验模态分解方法(Empirical Mode Decomposition,EMD)、LMID方法的端点效应轻微,具有较高的解凋精度;LMID方法可以精确分析振动能量的分布规律,有利于进一步识别爆破本身的力学作用特征。
文摘The present paper covers an X-ray photoelectron spectroscopic (XPS) method proposed for identifying Bronsted and Lewis acidic sites in zeolites and estimating acidic strength of these sites. It was found that the adsorption of pyridine on different acidic sites of H[M]-ZSM-5 zeolites exhibited three peaks: A (402.20-401.30 eV), B (400.95-400.40 eV) and C (399. 40-399. 10 eV). The peaks A and B are assigned to the N(?) level of pyridine adsorbed on Bronsted and Lewis acidic sites, and peak C is assigned to the N(?) level of pyridine adsorbed on a weak Lewis site and/or strongly physisorbed pyridine, respectively. The comparison of the ratio of the Bronsted and Lewis acidic sites determined from the relative intensities of the N(?), peaks with IR spectroscopic data shows that there is an inhomoge-neous distribution of Bronsted and Lewis acidic sites in H[M]-ZSM-5 zeolites. The N(?), binding energies of pyridine adsorbed on these zeolites directly reflect acidic strength, and these results are in good agreement with those observed in NH3-TPD experiments.
