Centrifugal slip casting in prefabricated template was used to prepare open-cell Al2O3 foams. Aqueous α- Al2O3 slurries with up to 50% solid contents (volume fraction) were prepared. The sedimentation of slurries dur...Centrifugal slip casting in prefabricated template was used to prepare open-cell Al2O3 foams. Aqueous α- Al2O3 slurries with up to 50% solid contents (volume fraction) were prepared. The sedimentation of slurries during centrifugation was discussed with respect to the hydronamic conditions at large particle concentrations. The effect of solid contents on mass segregation was observed. Segregation phenomena were hindered for slurries with high solid loadings exceeding 50% (volume fraction). The dried and sintered behaviors of samples were analyzed. The cell struts in green bodies had good particles packing and showed high green density (63.4% theory density). After sintered at 1500 ℃, the cell struts of final products had high sintered density (98.8% theory density) and homogeneous microstructure. The porosity of final products is 75.6%展开更多
An algorithm has been developed from various exiting techniques, that provides fully automatic cycle-slip detection at the data preprocessing stage. This algorithm, called pair linear combination, operates on undiffer...An algorithm has been developed from various exiting techniques, that provides fully automatic cycle-slip detection at the data preprocessing stage. This algorithm, called pair linear combination, operates on undifferenced or double-differenced, dual frequency carrier phase data, and requires the sampling interval is short. Test results carried out in a variety of situations including static and kinematic modes, short and long baseline situation, and low and high data rates were presented.展开更多
The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obta...The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obtain cell struts with high packing density.Aqueous Al2O3-ZrO2 slurries with up to 50 vol.% solid contents were prepared and the rheological characteristic of the slurries was investigated.Consolidation was performed at an acceleration of 2,860 g for 60 min.The effect of the characteristic of plant seeds on the drying behavior of Al2O3-ZrO2 green compact was analyzed.The effects of the solid contents of slurries on segregation phenomena of Al2O3 and ZrO2 particles and green compact uniformity were investigated.The compressive stress-strain curve and deformation behavior of Al2O3-ZrO2 ceramic foams prepared using plant seed template were analyzed.The results showed segregation phenomenon is negligible for highly stable slurry with 50 vol.% solid loading.The prepared cell struts of Al2O3-ZrO2 foams have high green density (61.9% TD), sintered density (99.1% TD) and homogeneous microstructure.When sintered at 1,550 ℃ for 2 h, the cell size of Al2O3-ZrO2 foam is approximately uniform and the diameter is about 1.1 mm.The porosity and compressive strength of sintered products is 66.2% and 5.86 MPa, respectively.展开更多
文摘Centrifugal slip casting in prefabricated template was used to prepare open-cell Al2O3 foams. Aqueous α- Al2O3 slurries with up to 50% solid contents (volume fraction) were prepared. The sedimentation of slurries during centrifugation was discussed with respect to the hydronamic conditions at large particle concentrations. The effect of solid contents on mass segregation was observed. Segregation phenomena were hindered for slurries with high solid loadings exceeding 50% (volume fraction). The dried and sintered behaviors of samples were analyzed. The cell struts in green bodies had good particles packing and showed high green density (63.4% theory density). After sintered at 1500 ℃, the cell struts of final products had high sintered density (98.8% theory density) and homogeneous microstructure. The porosity of final products is 75.6%
基金Project(40174005) supported by the National Natural Science Foundation of China
文摘An algorithm has been developed from various exiting techniques, that provides fully automatic cycle-slip detection at the data preprocessing stage. This algorithm, called pair linear combination, operates on undifferenced or double-differenced, dual frequency carrier phase data, and requires the sampling interval is short. Test results carried out in a variety of situations including static and kinematic modes, short and long baseline situation, and low and high data rates were presented.
基金supported by the National Natural Science Foundation of China (50672014)Innovation Research Team Program of the Ministry of Education (IRT0713)
文摘The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obtain cell struts with high packing density.Aqueous Al2O3-ZrO2 slurries with up to 50 vol.% solid contents were prepared and the rheological characteristic of the slurries was investigated.Consolidation was performed at an acceleration of 2,860 g for 60 min.The effect of the characteristic of plant seeds on the drying behavior of Al2O3-ZrO2 green compact was analyzed.The effects of the solid contents of slurries on segregation phenomena of Al2O3 and ZrO2 particles and green compact uniformity were investigated.The compressive stress-strain curve and deformation behavior of Al2O3-ZrO2 ceramic foams prepared using plant seed template were analyzed.The results showed segregation phenomenon is negligible for highly stable slurry with 50 vol.% solid loading.The prepared cell struts of Al2O3-ZrO2 foams have high green density (61.9% TD), sintered density (99.1% TD) and homogeneous microstructure.When sintered at 1,550 ℃ for 2 h, the cell size of Al2O3-ZrO2 foam is approximately uniform and the diameter is about 1.1 mm.The porosity and compressive strength of sintered products is 66.2% and 5.86 MPa, respectively.
