Background and Objective Large randomized controlled trials have demonstrated that percutaneous coronary intervention （PCI） with the routine use of drug-eluting stents is safe and effective, however, the patients ol...Background and Objective Large randomized controlled trials have demonstrated that percutaneous coronary intervention （PCI） with the routine use of drug-eluting stents is safe and effective, however, the patients older than 75 years undergoing PCI are at increased risk for major adverse cardiac events, so that the patients are usually excluded from this trial. The aim of the present study was to assess the early clinical outcome and risk factors in old patients with acute ST elevation myocardial infarction （STEMI） following primary PCI. Methods We analyzed the outcome after stenting in 136 patients older than 60 years in our coronary care unit with acute STEMI, and the patients were further classified in 2 age groups： patients≥75 years and 〈75 years. Results Though the older group had a higher prevalence of adverse baseline characteristics and lower final TIMI flow than those of the younger, the procedural success had no difference between two groups. The main adverse clinical events （MACE） for the old group was a little higher comparing with the younger in 12-month following up. Conclusions Our study suggest that drug-eluting stent implantation in elderly patients with acute ST elevation myocardial infarction has high initial procedural success rates despite having more severe baseline risk characteristics, and to shorten the time form symptom onset to PCI and improve final TIMI flow strategy may decrease MACE among old patients following PCI（J Geriatr Cardio12009; 6：67-70）.展开更多
The development status of the variable speed system of large power AC(alternating current)motor drive in China is introduced.The large power AC drive fed by AC-AC converters(cycloconverters)has developed greatly,and s...The development status of the variable speed system of large power AC(alternating current)motor drive in China is introduced.The large power AC drive fed by AC-AC converters(cycloconverters)has developed greatly,and some innovations on the theory and engineering technique have been realized.They have been applied to rolling mills,mine hoists,and so on,and remarkable economic and social benefit has been achieved.The development of AC drive fed by large power IGCT(integrated gate commutated thyristors)AC-DC-AC converter is also introduced.It has excellent performance and reliable operation,and has been used in traction.展开更多
Phosphorus （P） and metal （M） components were incorporated into promoters for enhancing FCC propylene yield, and the reactive behavior of promoters, before and after modification, were investigated. The results sho...Phosphorus （P） and metal （M） components were incorporated into promoters for enhancing FCC propylene yield, and the reactive behavior of promoters, before and after modification, were investigated. The results showed that both LPG and propylene yields were increased, and propylene selectivity was improved after the incorporation of P or M into the matrix, resulting in an increased C3 to C4 ratio in LPG during FCC process. But the sole incorporation of M into the matrix also led to an increase in coke and H2 yields on the other hand. Simultaneous modification of the matrix by P and M components resulted in more enhancement in propylene yield and selectivity along with little influence on FCC product distribution. Physico-chemical characterizations and model compound reactions were used to assist in analyzing the mechanism for improving propylene selectivity. Two types of active centers could strengthen the oligomerization of C4 olefins in LPG and these oligomers could be further cracked into C3 olefins on ZSM-5 zeolite, therefore maximizing the ratio of C3 to C4 in liquefied petroleum gas obtained during FCC process.展开更多
文摘Background and Objective Large randomized controlled trials have demonstrated that percutaneous coronary intervention （PCI） with the routine use of drug-eluting stents is safe and effective, however, the patients older than 75 years undergoing PCI are at increased risk for major adverse cardiac events, so that the patients are usually excluded from this trial. The aim of the present study was to assess the early clinical outcome and risk factors in old patients with acute ST elevation myocardial infarction （STEMI） following primary PCI. Methods We analyzed the outcome after stenting in 136 patients older than 60 years in our coronary care unit with acute STEMI, and the patients were further classified in 2 age groups： patients≥75 years and 〈75 years. Results Though the older group had a higher prevalence of adverse baseline characteristics and lower final TIMI flow than those of the younger, the procedural success had no difference between two groups. The main adverse clinical events （MACE） for the old group was a little higher comparing with the younger in 12-month following up. Conclusions Our study suggest that drug-eluting stent implantation in elderly patients with acute ST elevation myocardial infarction has high initial procedural success rates despite having more severe baseline risk characteristics, and to shorten the time form symptom onset to PCI and improve final TIMI flow strategy may decrease MACE among old patients following PCI（J Geriatr Cardio12009; 6：67-70）.
文摘The development status of the variable speed system of large power AC(alternating current)motor drive in China is introduced.The large power AC drive fed by AC-AC converters(cycloconverters)has developed greatly,and some innovations on the theory and engineering technique have been realized.They have been applied to rolling mills,mine hoists,and so on,and remarkable economic and social benefit has been achieved.The development of AC drive fed by large power IGCT(integrated gate commutated thyristors)AC-DC-AC converter is also introduced.It has excellent performance and reliable operation,and has been used in traction.
文摘Phosphorus （P） and metal （M） components were incorporated into promoters for enhancing FCC propylene yield, and the reactive behavior of promoters, before and after modification, were investigated. The results showed that both LPG and propylene yields were increased, and propylene selectivity was improved after the incorporation of P or M into the matrix, resulting in an increased C3 to C4 ratio in LPG during FCC process. But the sole incorporation of M into the matrix also led to an increase in coke and H2 yields on the other hand. Simultaneous modification of the matrix by P and M components resulted in more enhancement in propylene yield and selectivity along with little influence on FCC product distribution. Physico-chemical characterizations and model compound reactions were used to assist in analyzing the mechanism for improving propylene selectivity. Two types of active centers could strengthen the oligomerization of C4 olefins in LPG and these oligomers could be further cracked into C3 olefins on ZSM-5 zeolite, therefore maximizing the ratio of C3 to C4 in liquefied petroleum gas obtained during FCC process.
