In order to investigate the characteristics of re-oxidation of residual coal in goafs in close coal seam mining,scanning electron microscope and infrared spectrometer are used to study the changes of coal microstructu...In order to investigate the characteristics of re-oxidation of residual coal in goafs in close coal seam mining,scanning electron microscope and infrared spectrometer are used to study the changes of coal microstructure and chemical reaction of functional groups of eight coal samples at different ranks.Result shows that after initial oxidation,the surface morphology of pore are different,and the porosity of coal is increased and the oxygen adsorption capacity of coal is improved.The change of coal molecular structure and presence of a large amount of active oxygen-containing functional groups lead to increasing tendency of coal to further oxidation.In addition,the higher lever of the initial oxidation is,the easier the re-oxidation occurs.展开更多
本实验采用二次回归正交组合设计法优化了乙酰化黑木耳多糖的制备工艺,并对乙酰化前后黑木耳多糖的抗氧化活性进行了比较研究。实验以甲酰胺为溶剂,乙酸酐为酰化试剂,N-溴代琥珀酰亚胺(NBS)为催化剂,采用二次回归正交组合设计法,以反应...本实验采用二次回归正交组合设计法优化了乙酰化黑木耳多糖的制备工艺,并对乙酰化前后黑木耳多糖的抗氧化活性进行了比较研究。实验以甲酰胺为溶剂,乙酸酐为酰化试剂,N-溴代琥珀酰亚胺(NBS)为催化剂,采用二次回归正交组合设计法,以反应时间、反应温度、酰化试剂用量和NBS添加量为实验因素,采用羟胺比色法测定乙酰取代度的大小,以乙酰化取代度大小为实验指标,利用SPSS软件进行数据分析。结果表明,酰化试剂用量和NBS添加量对黑木耳多糖乙酰化有显著影响(p<0.05),经过方程运算,得到制备乙酰化黑木耳多糖的最优实验条件为,反应时间3.5 h,反应温度80.0℃,乙酰化试剂用量32.5 m L,NBS添加量为1.0%,在此实验条件下,得到的乙酰化取代度平均值为0.55。通过对原多糖和乙酰化多糖的红外光谱检测,显示乙酰化黑木耳多糖制备成功。抗氧化活性研究结果显示,黑木耳多糖乙酰化改性后清除羟自由基和超氧阴离子自由基的能力有所增加;还原能力也要比原料多糖有所提高。展开更多
Nanopowder MnO 2 was prepared with two oxidation reduction methods.XRD,SEM,FT IR and surface area measurement techniques were used to investigate properties of the MnO 2 powder.The results showed that the nano MnO 2 w...Nanopowder MnO 2 was prepared with two oxidation reduction methods.XRD,SEM,FT IR and surface area measurement techniques were used to investigate properties of the MnO 2 powder.The results showed that the nano MnO 2 with an average diameter in 30～50nm and good dispersity and high catalytic activity for H 2O 2 decomposition,can be synthesized with the two methods.With reduced crystal size of the powder,the infrared absorption peak of Mn O bond was blue shifted and fissioned,one shifted 61 19cm -1 and the other shifted 11 15cm -1 ,and the characteristic vibration bands of adsorption water were also blue shifted.展开更多
基金the National Key Foundation for Exploring Scientific Instruments of China(No.2012YQ24012705)the National Natural Science Foundation of China(No.51174113)+2 种基金the special fund for Scientific Research Institutes of China(Nos.2013EG122192 and 2014EG122293)CCTEG Innovation Foundation of China(No. 2014MS030)Shenhua Innovation Foundation of China(No. SHGF-13-07)
文摘In order to investigate the characteristics of re-oxidation of residual coal in goafs in close coal seam mining,scanning electron microscope and infrared spectrometer are used to study the changes of coal microstructure and chemical reaction of functional groups of eight coal samples at different ranks.Result shows that after initial oxidation,the surface morphology of pore are different,and the porosity of coal is increased and the oxygen adsorption capacity of coal is improved.The change of coal molecular structure and presence of a large amount of active oxygen-containing functional groups lead to increasing tendency of coal to further oxidation.In addition,the higher lever of the initial oxidation is,the easier the re-oxidation occurs.
文摘本实验采用二次回归正交组合设计法优化了乙酰化黑木耳多糖的制备工艺,并对乙酰化前后黑木耳多糖的抗氧化活性进行了比较研究。实验以甲酰胺为溶剂,乙酸酐为酰化试剂,N-溴代琥珀酰亚胺(NBS)为催化剂,采用二次回归正交组合设计法,以反应时间、反应温度、酰化试剂用量和NBS添加量为实验因素,采用羟胺比色法测定乙酰取代度的大小,以乙酰化取代度大小为实验指标,利用SPSS软件进行数据分析。结果表明,酰化试剂用量和NBS添加量对黑木耳多糖乙酰化有显著影响(p<0.05),经过方程运算,得到制备乙酰化黑木耳多糖的最优实验条件为,反应时间3.5 h,反应温度80.0℃,乙酰化试剂用量32.5 m L,NBS添加量为1.0%,在此实验条件下,得到的乙酰化取代度平均值为0.55。通过对原多糖和乙酰化多糖的红外光谱检测,显示乙酰化黑木耳多糖制备成功。抗氧化活性研究结果显示,黑木耳多糖乙酰化改性后清除羟自由基和超氧阴离子自由基的能力有所增加;还原能力也要比原料多糖有所提高。
文摘Nanopowder MnO 2 was prepared with two oxidation reduction methods.XRD,SEM,FT IR and surface area measurement techniques were used to investigate properties of the MnO 2 powder.The results showed that the nano MnO 2 with an average diameter in 30～50nm and good dispersity and high catalytic activity for H 2O 2 decomposition,can be synthesized with the two methods.With reduced crystal size of the powder,the infrared absorption peak of Mn O bond was blue shifted and fissioned,one shifted 61 19cm -1 and the other shifted 11 15cm -1 ,and the characteristic vibration bands of adsorption water were also blue shifted.
