Irregular shape catalysts with through-holes are new type catalysts developed recently. They are helpful to modify heat transfer character and to decrease the pressure drop of the fixed bed. This paper studied the inf...Irregular shape catalysts with through-holes are new type catalysts developed recently. They are helpful to modify heat transfer character and to decrease the pressure drop of the fixed bed. This paper studied the influence of irregular shape catalysts with through-holes on the pressure drop of the fixed bed and determined the equivalent diameter of irregular shape catalysts with through-holes. The equivalent diameter can be obtained by determining the pressure drop of the fixed bed packed with a certain catalyst. Equipment used to determine the equivalent diameters of catalysts is established. The equivalent diameters of three irregular shape catalysts were determined by Ergun equation.展开更多
A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication proc...A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication process of microelectrode,micro hole,silicon wafer and complex microstructure was discussed. The process rules of machining efficiency and the relative electrode wear rate as well as the machining mechanism and performance of silicon micro-EDM were also researched. Machining experiments showed that the microelectrode diameter as small as 6 μm and the micro hole with minimum size of 10 μm could be obtained steadily,and the maximum aspect ratios of microelectrode and micro hole were over 25 and 10 respectively. And silicon micro-EDM experiments showed that the micro beam with the aspect ratios over 15 could be obtained easily. And a micro beam with minimum size of 23 μm width on a silicon wafer with 420 μm thickness was achieved. At last,the microstructure machining technology for micro-EDM was also discussed. And a micro-facial sculpture with free space curved surface and size of 1 mm×0.3 mm×0.18 mm was also machined successfully.展开更多
文摘Irregular shape catalysts with through-holes are new type catalysts developed recently. They are helpful to modify heat transfer character and to decrease the pressure drop of the fixed bed. This paper studied the influence of irregular shape catalysts with through-holes on the pressure drop of the fixed bed and determined the equivalent diameter of irregular shape catalysts with through-holes. The equivalent diameter can be obtained by determining the pressure drop of the fixed bed packed with a certain catalyst. Equipment used to determine the equivalent diameters of catalysts is established. The equivalent diameters of three irregular shape catalysts were determined by Ergun equation.
文摘A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication process of microelectrode,micro hole,silicon wafer and complex microstructure was discussed. The process rules of machining efficiency and the relative electrode wear rate as well as the machining mechanism and performance of silicon micro-EDM were also researched. Machining experiments showed that the microelectrode diameter as small as 6 μm and the micro hole with minimum size of 10 μm could be obtained steadily,and the maximum aspect ratios of microelectrode and micro hole were over 25 and 10 respectively. And silicon micro-EDM experiments showed that the micro beam with the aspect ratios over 15 could be obtained easily. And a micro beam with minimum size of 23 μm width on a silicon wafer with 420 μm thickness was achieved. At last,the microstructure machining technology for micro-EDM was also discussed. And a micro-facial sculpture with free space curved surface and size of 1 mm×0.3 mm×0.18 mm was also machined successfully.
