Electropulsing rolling （ER） and warm rolling （WR） processes were performed to roll AZ31 magnesium alloy sheets. Mechanical properties, microstructure and texture evolution of these specimens were investigated afte...Electropulsing rolling （ER） and warm rolling （WR） processes were performed to roll AZ31 magnesium alloy sheets. Mechanical properties, microstructure and texture evolution of these specimens were investigated after rolling. The results indicate that electropulsing accelerates the recrystallization of AZ31 alloy sheets during hot rolling. After electropulsing rolling at a relatively low temperature, the microstructure of the sample shows fine equiaxed recrystallized grains with a lower density of dislocations and precipitates. In contrast, the microstructure of the sample after warm rolling shows elongated grain, numerous deformed twins, and a high density of dislocation and precipitates. Electropulsing rolling helps weaken the basal fiber texture. Although both the alloy sheets （ER and WR） have typical basal fiber texture, the maximum pole intensity of basal in ER sample is weaker. ER sheet has higher yield strength and elongation compared to WR sheet. As a promising technique, electropulsing rolling can be used to improve the microstructure and mechanical properties of materials.展开更多
Objective: To measure the calibration of different levels in aortic root andevaluate the relationships between the aortic sinuses and its neighbouring structure. Methods:Thirty heart specimens from cadaver of normal a...Objective: To measure the calibration of different levels in aortic root andevaluate the relationships between the aortic sinuses and its neighbouring structure. Methods:Thirty heart specimens from cadaver of normal adult were studied. The dimensions of four levels inaortic root were measured and the relationships between the aortic sinues and its neighbouringstructure were observed. Results: The dimensions of four levels in aortic root obtained as follows;Sinus > STJ1 > STJ0 > Base (P < 0.05) . The dimensions of the aortic valve leaflets were measured.The right coronary leaflet was larger than those of the left coronary and noncor-onary leaflets .But there was no statistical signiftcane (P > 0.05) . The relationships between the middle axis ofthe anterior valve of the bicuspid valve and the aortic sinuses were examined. The middle axis ofthe anterior valve in 26 specimens (86.6%) located between the left coronary sinus and thenoncoronary sinus . The relationship between the aortic prominence of the right atrium and theaortic sinuses was examined. The aortic prominence was formed from noncoronary sinus in 22 specimens(73.3%) . The relationship between the middle point of the right and left pulmonary valves and theaortic sinuses was examined. The middle point of the right and left pulmonary valves in 24 specimens(80%) was faced to the point between the right and left aortic sinuses . Conclusion: The dimensionof the four levels in aortic root is as follows, sinus > STJ1 > STJ0 > Base (P < 0.05) . There wasno statistical significance in the size of the three aortic valve leaflets (P > 0.05).展开更多
基金Project(13520503100)supported by the Science and Technology Commission Foundation of Shanghai Municipality,China
文摘Electropulsing rolling （ER） and warm rolling （WR） processes were performed to roll AZ31 magnesium alloy sheets. Mechanical properties, microstructure and texture evolution of these specimens were investigated after rolling. The results indicate that electropulsing accelerates the recrystallization of AZ31 alloy sheets during hot rolling. After electropulsing rolling at a relatively low temperature, the microstructure of the sample shows fine equiaxed recrystallized grains with a lower density of dislocations and precipitates. In contrast, the microstructure of the sample after warm rolling shows elongated grain, numerous deformed twins, and a high density of dislocation and precipitates. Electropulsing rolling helps weaken the basal fiber texture. Although both the alloy sheets （ER and WR） have typical basal fiber texture, the maximum pole intensity of basal in ER sample is weaker. ER sheet has higher yield strength and elongation compared to WR sheet. As a promising technique, electropulsing rolling can be used to improve the microstructure and mechanical properties of materials.
文摘Objective: To measure the calibration of different levels in aortic root andevaluate the relationships between the aortic sinuses and its neighbouring structure. Methods:Thirty heart specimens from cadaver of normal adult were studied. The dimensions of four levels inaortic root were measured and the relationships between the aortic sinues and its neighbouringstructure were observed. Results: The dimensions of four levels in aortic root obtained as follows;Sinus > STJ1 > STJ0 > Base (P < 0.05) . The dimensions of the aortic valve leaflets were measured.The right coronary leaflet was larger than those of the left coronary and noncor-onary leaflets .But there was no statistical signiftcane (P > 0.05) . The relationships between the middle axis ofthe anterior valve of the bicuspid valve and the aortic sinuses were examined. The middle axis ofthe anterior valve in 26 specimens (86.6%) located between the left coronary sinus and thenoncoronary sinus . The relationship between the aortic prominence of the right atrium and theaortic sinuses was examined. The aortic prominence was formed from noncoronary sinus in 22 specimens(73.3%) . The relationship between the middle point of the right and left pulmonary valves and theaortic sinuses was examined. The middle point of the right and left pulmonary valves in 24 specimens(80%) was faced to the point between the right and left aortic sinuses . Conclusion: The dimensionof the four levels in aortic root is as follows, sinus > STJ1 > STJ0 > Base (P < 0.05) . There wasno statistical significance in the size of the three aortic valve leaflets (P > 0.05).
