Background Coronary slow flow（CSF） during primary percutaneous coronary intervention（PCI） is closely related to the prognosis of patients with acute myocardial infarction（AMI）. Whether Enhanced External CounterP...Background Coronary slow flow（CSF） during primary percutaneous coronary intervention（PCI） is closely related to the prognosis of patients with acute myocardial infarction（AMI）. Whether Enhanced External CounterPulsation（EECP） could improve the phenomenon and enhance cardiac function in these patients has not been studied. Methods Seventy-eight AMI patients undergoing primary PCI were enrolled and divided into 2 groups, EECP group and sham group. In EECP group, the patients were treated with EECP for 30 min after coronary artery stent implantation; and in sham group, the patients after coronary artery stent implantation were treated with cuffs wrapped for 30 min. Hemodynamics and corrected TIMI Frame Count（c TFC） were recorded at different time points in both groups. CRP, HCY, NT-pro BNP and Killip class were also detected before operation and after treatment. Results In EECP group, compared to pre-and post-EECP treatment, the systolic blood pressure（SBP） was much lower（P〈0.05）, diastolic blood pressure（DBP） and mean arterial blood pressure（MBP）were much higher（P〈0.05）. The heart rate（HR） was not changed during EECP treatment（P〉0.05）. In sham group, SBP, DBP, MBP and HR were not significantly changed during these period（P〉0.05）. In EECP group,the c TFC of patients with CSF decreased significantly after treatment（P〈0.05）; and there was no difference in sham group（P〉0.05）. Compared with pre-EECP treatment, CRP and HCY were increased in post-EECP treatment of both groups（P〈0.05）, while, they were much lower in EECP group（P〈0.05）. The expression of NTpro BNP was decreased after treatment in both groups（P〈0.05）, and it was much lower in EECP group than in sham group（P〈0.05）. The Killip class was much lower after treatment than before operation in EECP group（P〈0.05）, and there was no change in sham group（P〉0.05）. Conclusions The results suggest that EECP is helpful in a short time to the improvement of CSF and recovery of cardiac function in AMI patients during primary PCI,and that CRP and HCY may be involved in this process.展开更多
In this paper, a new proof of superclose of a Crouzeix-Raviart type finite element is given for second order elliptic boundary value problem by Bramble-Hilbert lemma on anisotropic meshes.
Large-area erosions such as rust and obvious cavitation were found on the surface of the guide vane in Three Gorges hydropower units. A numerical explanation of the cavitation is given in this article. At first, based...Large-area erosions such as rust and obvious cavitation were found on the surface of the guide vane in Three Gorges hydropower units. A numerical explanation of the cavitation is given in this article. At first, based on the characteristic performance curves of the prototype hydro-turbine supplied by ALSTOM together with the actual operating conditions, an operating point is chosen for numerical analysis using the Reynolds-Averaged Navier-Stokes （RANS） equations. The flow passages from the inlet of the spiral case to the outlet of the draft tube are included in the computational domain. The results show that the static pressure on the guide vane surface is much higher than the critical pressure of cavitation. Secondly, a tiny protrusion on the guide vane surface is considered and the problem is simplified to a 2-D problem to study the local detailed flow near the guide vane surface. The protrusion is 0.5 mm in height and is 5.0 mm in width. On the basis of the results of RANS simulations, the 2-D problem is studied using the Large Eddy Simulation （LES）. It is shown that there exists a region in which the static pressure reaches a level below the vapor pressure of the water. Thirdly, a cavitation model is included for the 0.5 mm protrusion case and another tiny pit case, with a tiny pit 0.3 mm in depth and 1.0 mm in width. The results show that vapor bubble exists at the protrusion entrance and the pit exit as the low pressure regions.展开更多
With the consideration of the geometry of tilting pad journal bearing, a new form of the Reynolds equation was derived in this article. The film thickness, the squeeze motion of the journal and the rotation motion of ...With the consideration of the geometry of tilting pad journal bearing, a new form of the Reynolds equation was derived in this article. The film thickness, the squeeze motion of the journal and the rotation motion of the pad were explicitly contained in the equation. Based on this equation, together with the equilibrium equation of pad pivot, the water guide bearing used in the Gezhouba 10 F hydro-generator unit was numerically researched. The new Reynolds equation for the lubricating film was solved using Finite Volume （FV） discretization, Successive Over-Relaxation （SOR） iteration method and C＋＋ code are included. According to the numerical solution, and the stability of the film and the influences of the film thickness, the journal squeeze effect and the pad rotation effect on film force were discussed. The results indicate that the squeeze effect can not be neglected, although the rotation effect is negligible for both low-speed and high-speed bearings, so the computing time could be greatly reduced.展开更多
基金supported by Science and Technology Planning project of Guangdong Province(No.2012A03220005)
文摘Background Coronary slow flow（CSF） during primary percutaneous coronary intervention（PCI） is closely related to the prognosis of patients with acute myocardial infarction（AMI）. Whether Enhanced External CounterPulsation（EECP） could improve the phenomenon and enhance cardiac function in these patients has not been studied. Methods Seventy-eight AMI patients undergoing primary PCI were enrolled and divided into 2 groups, EECP group and sham group. In EECP group, the patients were treated with EECP for 30 min after coronary artery stent implantation; and in sham group, the patients after coronary artery stent implantation were treated with cuffs wrapped for 30 min. Hemodynamics and corrected TIMI Frame Count（c TFC） were recorded at different time points in both groups. CRP, HCY, NT-pro BNP and Killip class were also detected before operation and after treatment. Results In EECP group, compared to pre-and post-EECP treatment, the systolic blood pressure（SBP） was much lower（P〈0.05）, diastolic blood pressure（DBP） and mean arterial blood pressure（MBP）were much higher（P〈0.05）. The heart rate（HR） was not changed during EECP treatment（P〉0.05）. In sham group, SBP, DBP, MBP and HR were not significantly changed during these period（P〉0.05）. In EECP group,the c TFC of patients with CSF decreased significantly after treatment（P〈0.05）; and there was no difference in sham group（P〉0.05）. Compared with pre-EECP treatment, CRP and HCY were increased in post-EECP treatment of both groups（P〈0.05）, while, they were much lower in EECP group（P〈0.05）. The expression of NTpro BNP was decreased after treatment in both groups（P〈0.05）, and it was much lower in EECP group than in sham group（P〈0.05）. The Killip class was much lower after treatment than before operation in EECP group（P〈0.05）, and there was no change in sham group（P〉0.05）. Conclusions The results suggest that EECP is helpful in a short time to the improvement of CSF and recovery of cardiac function in AMI patients during primary PCI,and that CRP and HCY may be involved in this process.
基金Supported by the NSF of China(10471133)Supported by the NSF of Henan Province(0611053100)Supported by the NSF of Education Committee of Henan Province(2006110011)
文摘In this paper, a new proof of superclose of a Crouzeix-Raviart type finite element is given for second order elliptic boundary value problem by Bramble-Hilbert lemma on anisotropic meshes.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50975103 and 51006039)
文摘Large-area erosions such as rust and obvious cavitation were found on the surface of the guide vane in Three Gorges hydropower units. A numerical explanation of the cavitation is given in this article. At first, based on the characteristic performance curves of the prototype hydro-turbine supplied by ALSTOM together with the actual operating conditions, an operating point is chosen for numerical analysis using the Reynolds-Averaged Navier-Stokes （RANS） equations. The flow passages from the inlet of the spiral case to the outlet of the draft tube are included in the computational domain. The results show that the static pressure on the guide vane surface is much higher than the critical pressure of cavitation. Secondly, a tiny protrusion on the guide vane surface is considered and the problem is simplified to a 2-D problem to study the local detailed flow near the guide vane surface. The protrusion is 0.5 mm in height and is 5.0 mm in width. On the basis of the results of RANS simulations, the 2-D problem is studied using the Large Eddy Simulation （LES）. It is shown that there exists a region in which the static pressure reaches a level below the vapor pressure of the water. Thirdly, a cavitation model is included for the 0.5 mm protrusion case and another tiny pit case, with a tiny pit 0.3 mm in depth and 1.0 mm in width. The results show that vapor bubble exists at the protrusion entrance and the pit exit as the low pressure regions.
文摘With the consideration of the geometry of tilting pad journal bearing, a new form of the Reynolds equation was derived in this article. The film thickness, the squeeze motion of the journal and the rotation motion of the pad were explicitly contained in the equation. Based on this equation, together with the equilibrium equation of pad pivot, the water guide bearing used in the Gezhouba 10 F hydro-generator unit was numerically researched. The new Reynolds equation for the lubricating film was solved using Finite Volume （FV） discretization, Successive Over-Relaxation （SOR） iteration method and C＋＋ code are included. According to the numerical solution, and the stability of the film and the influences of the film thickness, the journal squeeze effect and the pad rotation effect on film force were discussed. The results indicate that the squeeze effect can not be neglected, although the rotation effect is negligible for both low-speed and high-speed bearings, so the computing time could be greatly reduced.
