采用浸渍法制备Co-β-SBA-15催化剂,通过XRD、BET和FT-IR等对其进行表征与分析,结果发现,该催化剂具有良好的稳定性。将其应用于模拟柴油的催化氧化脱硫反应中,在模拟柴油用量为30 m L、氧化剂用量为4 m L、萃取剂用量为30 m L、催化剂...采用浸渍法制备Co-β-SBA-15催化剂,通过XRD、BET和FT-IR等对其进行表征与分析,结果发现,该催化剂具有良好的稳定性。将其应用于模拟柴油的催化氧化脱硫反应中,在模拟柴油用量为30 m L、氧化剂用量为4 m L、萃取剂用量为30 m L、催化剂质量为0. 5 g、反应温度为70℃、反应时间为2 h的最佳工艺条件下,模拟柴油的脱硫率达到97. 71%。展开更多
Numerical investigations on the flow field in Ti-Al melt during rectangular cold crucible directional solidification were carried out. Combined with the experimental results, 3-D finite element models for calculating ...Numerical investigations on the flow field in Ti-Al melt during rectangular cold crucible directional solidification were carried out. Combined with the experimental results, 3-D finite element models for calculating flow field inside melting pool were established, the characteristics of the flow under different power parameters were further studied. Numerical calculation results show that there is a complex circular flow in the melt, a rapid horizontal flow exists on the solid/liquid interface and those flows confluence in the center of the melting pool. The flow velocity v increases with the increase of current intensity, but the flow patterns remain unchanged. When the current is 1000 A, the vmax reaches 4 mm/s and the flow on the interface achieves 3 mm/s. Flow patterns are quite different when the frequency changes from 10 kHz to 100 kHz, the mechanism of the frequency influence on the flow pattern is analyzed, and there is an optimum frequency for cold crucible directional solidification.展开更多
The parameters and factors that influence the surface quality and macrostructure of titanium alloy with reactive properties under liquid state were studied experimentally using a cold crucible electromagnetic casting ...The parameters and factors that influence the surface quality and macrostructure of titanium alloy with reactive properties under liquid state were studied experimentally using a cold crucible electromagnetic casting method. The variations in the process parameters have great impact on the surface quality and macrostructure of cast billets. Billets with crack free and smooth surfaces as well as directional solidified primary structures were obtained after the selection of optimized process parameters. The formation mechanisms of defects such as cracks and non-directional structural morphology were interpreted briefly. Finally,the casting of billets with good outer qualities and inner column grains has been attained successfully,which in turn gives a solid foundation for further development of the technology.展开更多
Experiments of continuous and directional solidification of titanium alloy slabs were performed using authors-designed multi-function directional solidification apparatus with rectangular cold crucible. Influences of ...Experiments of continuous and directional solidification of titanium alloy slabs were performed using authors-designed multi-function directional solidification apparatus with rectangular cold crucible. Influences of processing parameters on the surface qualities of the solidified slabs were studied. It is shown that the slab surface qualities can be effectively improved with increasing of the turns in coil and input power, and with decreasing of withdrawal velocity and relatively low position of pedestal to the induction coil. The influences of the processing parameters in the descending order are as follows: the turns in coil, input power, withdrawal velocity and the relative position of pedestal. With optimized parameters, quality slabs free from cracks and ripples were obtained. The solidified structure with good surface quality shows directionally solidified structure.展开更多
In this paper Nd-Fe-B ingots with hyper-peritectic composition were prepared through continuous and directional solidification by a novel electromagnetic cold crucible approach.A group of experiments were carried out ...In this paper Nd-Fe-B ingots with hyper-peritectic composition were prepared through continuous and directional solidification by a novel electromagnetic cold crucible approach.A group of experiments were carried out in order to investigate the effects of input power and withdrawal velocity on the microstructure and growth orientation of Nd-Fe-B phases.It was found that the peritectic Nd;Fe;B phase grows with a planar interface at lower withdrawal velocity and changed into the dendritic interface at higher withdrawal velocity.The result was explained by the theory of constitutional supercooling.Meanwhile the volume fraction of ferromagnetic T;phase was found to be increased first and then decreased with the increasing of withdrawal velocity during the growth process of the ingots.展开更多
文摘采用浸渍法制备Co-β-SBA-15催化剂,通过XRD、BET和FT-IR等对其进行表征与分析,结果发现,该催化剂具有良好的稳定性。将其应用于模拟柴油的催化氧化脱硫反应中,在模拟柴油用量为30 m L、氧化剂用量为4 m L、萃取剂用量为30 m L、催化剂质量为0. 5 g、反应温度为70℃、反应时间为2 h的最佳工艺条件下,模拟柴油的脱硫率达到97. 71%。
基金Project (2011CB605504) supported by the National Basic Research Program of China
文摘Numerical investigations on the flow field in Ti-Al melt during rectangular cold crucible directional solidification were carried out. Combined with the experimental results, 3-D finite element models for calculating flow field inside melting pool were established, the characteristics of the flow under different power parameters were further studied. Numerical calculation results show that there is a complex circular flow in the melt, a rapid horizontal flow exists on the solid/liquid interface and those flows confluence in the center of the melting pool. The flow velocity v increases with the increase of current intensity, but the flow patterns remain unchanged. When the current is 1000 A, the vmax reaches 4 mm/s and the flow on the interface achieves 3 mm/s. Flow patterns are quite different when the frequency changes from 10 kHz to 100 kHz, the mechanism of the frequency influence on the flow pattern is analyzed, and there is an optimum frequency for cold crucible directional solidification.
基金This work was supported by the National Key Fundamental Research Development Program of China (G200067202-2)the Natural Science Fund of China (50395102).
文摘The parameters and factors that influence the surface quality and macrostructure of titanium alloy with reactive properties under liquid state were studied experimentally using a cold crucible electromagnetic casting method. The variations in the process parameters have great impact on the surface quality and macrostructure of cast billets. Billets with crack free and smooth surfaces as well as directional solidified primary structures were obtained after the selection of optimized process parameters. The formation mechanisms of defects such as cracks and non-directional structural morphology were interpreted briefly. Finally,the casting of billets with good outer qualities and inner column grains has been attained successfully,which in turn gives a solid foundation for further development of the technology.
基金The paper is supported by Natural Science Foundation of China, 50395102 and National Key Fundamental ResearchDevelopment Program of China, G200067202-2.
文摘Experiments of continuous and directional solidification of titanium alloy slabs were performed using authors-designed multi-function directional solidification apparatus with rectangular cold crucible. Influences of processing parameters on the surface qualities of the solidified slabs were studied. It is shown that the slab surface qualities can be effectively improved with increasing of the turns in coil and input power, and with decreasing of withdrawal velocity and relatively low position of pedestal to the induction coil. The influences of the processing parameters in the descending order are as follows: the turns in coil, input power, withdrawal velocity and the relative position of pedestal. With optimized parameters, quality slabs free from cracks and ripples were obtained. The solidified structure with good surface quality shows directionally solidified structure.
基金Item Sponsored by National Natural Science Foundation of China[No.51171053]Harbin Excellent Discipline Leaders Foundation[2011RFXXG004]
文摘In this paper Nd-Fe-B ingots with hyper-peritectic composition were prepared through continuous and directional solidification by a novel electromagnetic cold crucible approach.A group of experiments were carried out in order to investigate the effects of input power and withdrawal velocity on the microstructure and growth orientation of Nd-Fe-B phases.It was found that the peritectic Nd;Fe;B phase grows with a planar interface at lower withdrawal velocity and changed into the dendritic interface at higher withdrawal velocity.The result was explained by the theory of constitutional supercooling.Meanwhile the volume fraction of ferromagnetic T;phase was found to be increased first and then decreased with the increasing of withdrawal velocity during the growth process of the ingots.
