One-dimensional alumina photonic crystals with defect modes were successfully fabricated through inserting a constant voltage waveform into the periodic voltage signals. The trans-mission spectra show that the thickne...One-dimensional alumina photonic crystals with defect modes were successfully fabricated through inserting a constant voltage waveform into the periodic voltage signals. The trans-mission spectra show that the thickness of defects plays a key role in determining the trans-mittance of defect modes. When the thickness was ？180 nm, an obvious defect mode with the high transmittance of 55% and a narrow full width at half maximum of 18 nm was observed in the original photonic band gaps. The defect mode shifted linearly with the increasing of refractive index of the analytes infiltrated into pores, indicating its potential application in chemical sensing or bio-sensing.展开更多
During the plasma spheroidization process powders undergo different changes in their microstructures and crystal phases. In this paper, simple calculation of heat transfer between the plasma and a suspended particle w...During the plasma spheroidization process powders undergo different changes in their microstructures and crystal phases. In this paper, simple calculation of heat transfer between the plasma and a suspended particle was performed based on three hypotheses for the purpose of guiding experiments. Experimental investigation of the crystal phases and microstructural changes during the plasma processing was made using silica, alumina and nickel powders as starting materials. It has been revealed from the experimental results that these materials undergo different changes in crystal phases and microstructures, and these changes are essentially determined by the structures, properties and aggregate states of the starting materials.展开更多
Industrial catalyst waste has emerged as a hazardous pollutant that requires safe and proper disposal after the unloading process.Finding a valuable and sustainable strategy for its treatment is a significant challeng...Industrial catalyst waste has emerged as a hazardous pollutant that requires safe and proper disposal after the unloading process.Finding a valuable and sustainable strategy for its treatment is a significant challenge compared to traditional methods.In this study,we present a facile method for the recovery of molybdenum and aluminum contents from spent Mo-Ni/Al_(2)O_(3) hydrogenation catalysts through crystallization separation and coprecipitation.Furthermore,the recovered molybdenum and aluminum are utilized as active metals and carriers for the preparation of new catalysts.Their properties were thoroughly analyzed and investigated using various characterization techniques.The hydrogenation activity of these newly prepared catalysts was evaluated on a fixed-bed small-scale device and compared with a reference catalyst synthesized from commercial raw reagents.Finally,the hydrogenation activity of the catalysts was further assessed by using the entire distillate oil of coal liquefaction as the raw oil,specifically focusing on denitrogenation and aromatic saturation.This work not only offers an effective solution for recycling catalysts but also promotes sustainable development.展开更多
The effect of 20 kHz ultrasound on alumina hydrate precipitation from seeded sodium aluminate solution was studied. Compared with alumina hydrate precipitation without treatment of ultrasound, the precipitation time i...The effect of 20 kHz ultrasound on alumina hydrate precipitation from seeded sodium aluminate solution was studied. Compared with alumina hydrate precipitation without treatment of ultrasound, the precipitation time is reduced from 30 h to 15 h when the precipitation ratio is 45% under 20 kHz ultrasound. Furthermore, agglomeration is increased and the growth rate of alumina hydrate is increased under 20 kHz ultrasound by comparing the crystal size distribution and the SEM photographs. As a result, the average size of alumina hydrate is increased by 3.7 μm. The structure of product is not changed according to the results of X ray powder deflection.展开更多
The effects of Al2O3 on the crystallization behavior of glass compositions in the Na2O-CaO-P2O5-SiO2 system were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron micro...The effects of Al2O3 on the crystallization behavior of glass compositions in the Na2O-CaO-P2O5-SiO2 system were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In this system, thermal parameters of glasses were studied by DTA. The density of the glass ceramic samples was measured by Archimedes’ method. It was found that the glass-ceramic containing 2.0 molar percent Al2O3 had desirable sintering behavior and reached to an acceptable density. Phase investigation and micro structural study were performed by XRD and SEM, respectively.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Basic Research Program of China （No.2012CB932303）,the National Natural Science Foundation of China （No.11074254 and No.51171176）, Hundred Talent Program of Chinese Academy of Sciences, and the President Foundation of Hefei Institute of Physical Sciences.
文摘One-dimensional alumina photonic crystals with defect modes were successfully fabricated through inserting a constant voltage waveform into the periodic voltage signals. The trans-mission spectra show that the thickness of defects plays a key role in determining the trans-mittance of defect modes. When the thickness was ？180 nm, an obvious defect mode with the high transmittance of 55% and a narrow full width at half maximum of 18 nm was observed in the original photonic band gaps. The defect mode shifted linearly with the increasing of refractive index of the analytes infiltrated into pores, indicating its potential application in chemical sensing or bio-sensing.
基金supported by National Natural Science Foundation of China (No.50574083)
文摘During the plasma spheroidization process powders undergo different changes in their microstructures and crystal phases. In this paper, simple calculation of heat transfer between the plasma and a suspended particle was performed based on three hypotheses for the purpose of guiding experiments. Experimental investigation of the crystal phases and microstructural changes during the plasma processing was made using silica, alumina and nickel powders as starting materials. It has been revealed from the experimental results that these materials undergo different changes in crystal phases and microstructures, and these changes are essentially determined by the structures, properties and aggregate states of the starting materials.
基金supported by grants from the National Key Research and Development Program of China(2023YE41507601)the National Natural Science Foundation of China(22122807,22378038)+1 种基金the Fundamental Research Funds for the Central Universities(DUT23RC(3)044)State Key Laboratory of Heavy Oil Processing,China University of Petroleum(WX20230149)。
文摘Industrial catalyst waste has emerged as a hazardous pollutant that requires safe and proper disposal after the unloading process.Finding a valuable and sustainable strategy for its treatment is a significant challenge compared to traditional methods.In this study,we present a facile method for the recovery of molybdenum and aluminum contents from spent Mo-Ni/Al_(2)O_(3) hydrogenation catalysts through crystallization separation and coprecipitation.Furthermore,the recovered molybdenum and aluminum are utilized as active metals and carriers for the preparation of new catalysts.Their properties were thoroughly analyzed and investigated using various characterization techniques.The hydrogenation activity of these newly prepared catalysts was evaluated on a fixed-bed small-scale device and compared with a reference catalyst synthesized from commercial raw reagents.Finally,the hydrogenation activity of the catalysts was further assessed by using the entire distillate oil of coal liquefaction as the raw oil,specifically focusing on denitrogenation and aromatic saturation.This work not only offers an effective solution for recycling catalysts but also promotes sustainable development.
文摘The effect of 20 kHz ultrasound on alumina hydrate precipitation from seeded sodium aluminate solution was studied. Compared with alumina hydrate precipitation without treatment of ultrasound, the precipitation time is reduced from 30 h to 15 h when the precipitation ratio is 45% under 20 kHz ultrasound. Furthermore, agglomeration is increased and the growth rate of alumina hydrate is increased under 20 kHz ultrasound by comparing the crystal size distribution and the SEM photographs. As a result, the average size of alumina hydrate is increased by 3.7 μm. The structure of product is not changed according to the results of X ray powder deflection.
文摘The effects of Al2O3 on the crystallization behavior of glass compositions in the Na2O-CaO-P2O5-SiO2 system were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In this system, thermal parameters of glasses were studied by DTA. The density of the glass ceramic samples was measured by Archimedes’ method. It was found that the glass-ceramic containing 2.0 molar percent Al2O3 had desirable sintering behavior and reached to an acceptable density. Phase investigation and micro structural study were performed by XRD and SEM, respectively.
