建立了顶空进样法—芯片级非对称场离子迁移谱(Microchip-based FAIMS)技术快速识别霉变烟草。在常压条件下,以经过活性炭和分子筛净化的空气为载气,同时在正负离子模式下进行检测。在优化的条件下(载气流量2000 m L/min,顶空温度为25℃...建立了顶空进样法—芯片级非对称场离子迁移谱(Microchip-based FAIMS)技术快速识别霉变烟草。在常压条件下,以经过活性炭和分子筛净化的空气为载气,同时在正负离子模式下进行检测。在优化的条件下(载气流量2000 m L/min,顶空温度为25℃,样品气流为100 m L/min),对不同霉变程度烟草进行定性分析,建立识别规则,依据规则识别烟草霉变程度,识别率达90%以上,实现对203种烟草的快速检测。对得到不同烟草的特征峰,利用解析-气相色谱-质谱仪器(TD-GC-MS)定性分析不同霉变状态烟草的特征霉变物质,验证FAIMS测试结果。烟草特征峰在指定的CV值和DF值下,离子电流值值存在显著性差异,利于识别。方法重复性的相对标准偏差RSD≤5%。因此,FAIMS检测技术可用于快速识别霉变烟草的方法开发。展开更多
In this study,a MnOx@TiO2 core‐shell catalyst prepared by a two‐step method was used for the low‐temperature selective catalytic reduction of NOx with NH3.The catalyst exhibits high activity,high stability,and exce...In this study,a MnOx@TiO2 core‐shell catalyst prepared by a two‐step method was used for the low‐temperature selective catalytic reduction of NOx with NH3.The catalyst exhibits high activity,high stability,and excellent N2 selectivity.Furthermore,it displays better SO2 and H2O tolerance than its MnOx,TiO2,and MnOx/TiO2 counterparts.The prepared catalyst was characterized systematically by transmission electron microscopy,high‐resolution transmission electron microscopy,X‐ray diffraction,Raman,BET,X‐ray photoelectron spectroscopy,NH3 temperature‐programmed desorption and H2 temperature‐programmed reduction analyses.The optimized MnOx@TiO2 catalyst exhibits an obvious core‐shell structure,where the TiO2 shell is evenly distributed over the MnOx nanorod core.The catalyst also presents abundant mesopores,Lewis‐acid sites,and high redox capability,all of which enhance its catalytic performance.According to the XPS results,the decrease in the number of Mn4+active centers after SO2 poisoning is significantly lower in MnOx@TiO2 than in MnOx/TiO2.The core‐shell structure is hence able to protect the catalytic active sites from H2O and SO2 poisoning.展开更多
目的建立近红外光谱法快速检测山茱萸中莫诺苷和马钱苷含量的分析方法。方法利用近红外光谱仪扫描粉碎后的山茱萸药材样品,对其光谱进行预处理和波段选择,并结合偏最小二乘法(partial least squares,PLS)建立莫诺苷和马钱苷含量快速无...目的建立近红外光谱法快速检测山茱萸中莫诺苷和马钱苷含量的分析方法。方法利用近红外光谱仪扫描粉碎后的山茱萸药材样品,对其光谱进行预处理和波段选择,并结合偏最小二乘法(partial least squares,PLS)建立莫诺苷和马钱苷含量快速无损检测方法。结果所建立的模型的决定系数R分别为0.9668、0.9062,交叉验证均方根差值分别为0.059、0.047,对验证集样品进行预测并统计分析,预测值与真实值之间无显著差异(P>0.05)。结论所建立的模型准确度高,适用于山茱萸药材粉末的莫诺苷和马钱苷含量的快速检测。展开更多
文摘建立了顶空进样法—芯片级非对称场离子迁移谱(Microchip-based FAIMS)技术快速识别霉变烟草。在常压条件下,以经过活性炭和分子筛净化的空气为载气,同时在正负离子模式下进行检测。在优化的条件下(载气流量2000 m L/min,顶空温度为25℃,样品气流为100 m L/min),对不同霉变程度烟草进行定性分析,建立识别规则,依据规则识别烟草霉变程度,识别率达90%以上,实现对203种烟草的快速检测。对得到不同烟草的特征峰,利用解析-气相色谱-质谱仪器(TD-GC-MS)定性分析不同霉变状态烟草的特征霉变物质,验证FAIMS测试结果。烟草特征峰在指定的CV值和DF值下,离子电流值值存在显著性差异,利于识别。方法重复性的相对标准偏差RSD≤5%。因此,FAIMS检测技术可用于快速识别霉变烟草的方法开发。
文摘In this study,a MnOx@TiO2 core‐shell catalyst prepared by a two‐step method was used for the low‐temperature selective catalytic reduction of NOx with NH3.The catalyst exhibits high activity,high stability,and excellent N2 selectivity.Furthermore,it displays better SO2 and H2O tolerance than its MnOx,TiO2,and MnOx/TiO2 counterparts.The prepared catalyst was characterized systematically by transmission electron microscopy,high‐resolution transmission electron microscopy,X‐ray diffraction,Raman,BET,X‐ray photoelectron spectroscopy,NH3 temperature‐programmed desorption and H2 temperature‐programmed reduction analyses.The optimized MnOx@TiO2 catalyst exhibits an obvious core‐shell structure,where the TiO2 shell is evenly distributed over the MnOx nanorod core.The catalyst also presents abundant mesopores,Lewis‐acid sites,and high redox capability,all of which enhance its catalytic performance.According to the XPS results,the decrease in the number of Mn4+active centers after SO2 poisoning is significantly lower in MnOx@TiO2 than in MnOx/TiO2.The core‐shell structure is hence able to protect the catalytic active sites from H2O and SO2 poisoning.
文摘目的建立近红外光谱法快速检测山茱萸中莫诺苷和马钱苷含量的分析方法。方法利用近红外光谱仪扫描粉碎后的山茱萸药材样品,对其光谱进行预处理和波段选择,并结合偏最小二乘法(partial least squares,PLS)建立莫诺苷和马钱苷含量快速无损检测方法。结果所建立的模型的决定系数R分别为0.9668、0.9062,交叉验证均方根差值分别为0.059、0.047,对验证集样品进行预测并统计分析,预测值与真实值之间无显著差异(P>0.05)。结论所建立的模型准确度高,适用于山茱萸药材粉末的莫诺苷和马钱苷含量的快速检测。
