The atomic structure and transition properties of H-like Al embedded in hot and dense plasmas are investigated using modified GRASP2 K code. The plasma screening effect on the nucleus is described using the self-consi...The atomic structure and transition properties of H-like Al embedded in hot and dense plasmas are investigated using modified GRASP2 K code. The plasma screening effect on the nucleus is described using the self-consistent field ion sphere model. The effective nuclear potential decreases much more quickly with increasing average free electron density,but increases slightly with increasing electron temperature. The variations of the transition energies, transition probabilities,and oscillator strengths with the free electron density and electron temperature are the same as that of the effective nuclear potential. The results reported in this work agree well with other available theoretical results and are useful for plasma diagnostics.展开更多
Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculation...Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculations. For the minimization of H[Al]ZSM 5, significant geometric rearrangements have been investigated in the local environments of Brnsted acidic sites, which resulted from the isomorphous substitution of Al for Si atoms in MFI framework.展开更多
Sulfonated catalysts based on zirconia (SO3</sub>H-ZrO2</sub>), silica (SO3</sub>H-SBA-15) and zeolite (SO3</sub>H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a...Sulfonated catalysts based on zirconia (SO3</sub>H-ZrO2</sub>), silica (SO3</sub>H-SBA-15) and zeolite (SO3</sub>H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a microwave reactor. The prepared catalysts were characterized by various techniques (XRD, N2</sub> physisorption at 77 K, SEM, TEM and NH3</sub>-TPD). The obtained results reveal that despite the differences in their structural and textural properties, the ZrO2</sub>, Al-SBA-15 and H-ZSM-5 supports show similar conversions. Doping supports with sulfonate species created hydrogen bonds between SO3</sub>H groups and increased the amount of weak acid sites, which enhanced the hydrolysis of hemicellulose. SO3</sub>H- ZSM-5 showed the highest catalytic activity followed by SO3</sub>H-SBA-15 while SO3</sub>H-ZrO2</sub> exhibited a poor conversion. Furthermore, the catalytic hydrolysis of the hemicellulose leads to several interesting products, such as formic acid, acetic acid, lactic acid and xylan. The correlation between the catalytic performances and the acidic properties of the different samples indicates that the best catalytic performances were obtained with the least acidic solids and especially when the density of strong acid sites decreases.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11474208 and 11565018)the Department of Education Fund Item of Gansu Province,China(Grant No.2015B-109)the Doctoral Scientific Fund Project of Longdong University,China(Grant No.XYBY1601)
文摘The atomic structure and transition properties of H-like Al embedded in hot and dense plasmas are investigated using modified GRASP2 K code. The plasma screening effect on the nucleus is described using the self-consistent field ion sphere model. The effective nuclear potential decreases much more quickly with increasing average free electron density,but increases slightly with increasing electron temperature. The variations of the transition energies, transition probabilities,and oscillator strengths with the free electron density and electron temperature are the same as that of the effective nuclear potential. The results reported in this work agree well with other available theoretical results and are useful for plasma diagnostics.
文摘Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculations. For the minimization of H[Al]ZSM 5, significant geometric rearrangements have been investigated in the local environments of Brnsted acidic sites, which resulted from the isomorphous substitution of Al for Si atoms in MFI framework.
文摘Sulfonated catalysts based on zirconia (SO3</sub>H-ZrO2</sub>), silica (SO3</sub>H-SBA-15) and zeolite (SO3</sub>H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a microwave reactor. The prepared catalysts were characterized by various techniques (XRD, N2</sub> physisorption at 77 K, SEM, TEM and NH3</sub>-TPD). The obtained results reveal that despite the differences in their structural and textural properties, the ZrO2</sub>, Al-SBA-15 and H-ZSM-5 supports show similar conversions. Doping supports with sulfonate species created hydrogen bonds between SO3</sub>H groups and increased the amount of weak acid sites, which enhanced the hydrolysis of hemicellulose. SO3</sub>H- ZSM-5 showed the highest catalytic activity followed by SO3</sub>H-SBA-15 while SO3</sub>H-ZrO2</sub> exhibited a poor conversion. Furthermore, the catalytic hydrolysis of the hemicellulose leads to several interesting products, such as formic acid, acetic acid, lactic acid and xylan. The correlation between the catalytic performances and the acidic properties of the different samples indicates that the best catalytic performances were obtained with the least acidic solids and especially when the density of strong acid sites decreases.
