The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifie...The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifier side and LCC on inverter side,is investigated,and its mathematic model is deduced.The commutation failure issue of the LCC converter in the hybrid-HVDC system is considered,and a novel coordinated control method is proposed to enhance the system commutation failure immunity.A voltage dependent voltage order limiter(VDVOL)is designed based on the constant DC voltage control on the rectifier side,and constant extinction angle backup control is introduced based on the constant DC current control with voltage dependent current order limiter(VDCOL)on the inverter side.The hybrid-HVDC system performances under normal operation state and fault state are simulated in the PSCAD/EMTDC.Then,system transient state performances with or without the proposed control methods under fault condition are further compared and analyzed.It is concluded that the proposed control method has the ability to effectively reduce the probability of commutation failure and improve the fault recovery performance of the hybrid-HVDC system.展开更多
Background Interleukin （IL）-10, IL-6 and their ratio （IL-6/IL-10） play an important role in the risk of developing coronary artery disease, and may correlate with its outcomes. Few clinical trials have investigate...Background Interleukin （IL）-10, IL-6 and their ratio （IL-6/IL-10） play an important role in the risk of developing coronary artery disease, and may correlate with its outcomes. Few clinical trials have investigated the prognostic impact of these factors on long-term car- diovascular events in patients presented with chest pain. Methods A prospective study was performed on 566 patients admitted with chest pain and identified mild to moderate coronary artery lesions. 1L-10, IL-6 and IL-6/IL-10 were measured. Results A total of 511 patients com- pleted the follow-up. The median follow-up time was 74 months. Kaplan-Meier analysis demonstrated a clear increase of the incidence of major adverse cardiac events during the follow-up period in patients with below-median levels of IL-10 （P = 0.006） and above-median levels of IL-6/IL-10 （P = 0.012）. Multivariate Cox proportional hazards analysis indicated the IL-10 levels to be strong independent predictors after adjustment for underlying confounders. Conclusions Elevated IL-10 levels are associated with a more favorable long-term prognosis in patients with chest pain and mild to moderate coronary artery lesions. IL-10 could be used for early risk assessment of long-term prognosis.展开更多
基金supported by the National High Technology Research and Development Program of China("863" Program)(Grant No.2013AA050105)the National Natural Science Foundation of China(Grant No.51177042)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.13QN03)2012 science and technology projects of State Grid Corporation of China(Grant No.XT71-12-015)
文摘The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifier side and LCC on inverter side,is investigated,and its mathematic model is deduced.The commutation failure issue of the LCC converter in the hybrid-HVDC system is considered,and a novel coordinated control method is proposed to enhance the system commutation failure immunity.A voltage dependent voltage order limiter(VDVOL)is designed based on the constant DC voltage control on the rectifier side,and constant extinction angle backup control is introduced based on the constant DC current control with voltage dependent current order limiter(VDCOL)on the inverter side.The hybrid-HVDC system performances under normal operation state and fault state are simulated in the PSCAD/EMTDC.Then,system transient state performances with or without the proposed control methods under fault condition are further compared and analyzed.It is concluded that the proposed control method has the ability to effectively reduce the probability of commutation failure and improve the fault recovery performance of the hybrid-HVDC system.
文摘Background Interleukin （IL）-10, IL-6 and their ratio （IL-6/IL-10） play an important role in the risk of developing coronary artery disease, and may correlate with its outcomes. Few clinical trials have investigated the prognostic impact of these factors on long-term car- diovascular events in patients presented with chest pain. Methods A prospective study was performed on 566 patients admitted with chest pain and identified mild to moderate coronary artery lesions. 1L-10, IL-6 and IL-6/IL-10 were measured. Results A total of 511 patients com- pleted the follow-up. The median follow-up time was 74 months. Kaplan-Meier analysis demonstrated a clear increase of the incidence of major adverse cardiac events during the follow-up period in patients with below-median levels of IL-10 （P = 0.006） and above-median levels of IL-6/IL-10 （P = 0.012）. Multivariate Cox proportional hazards analysis indicated the IL-10 levels to be strong independent predictors after adjustment for underlying confounders. Conclusions Elevated IL-10 levels are associated with a more favorable long-term prognosis in patients with chest pain and mild to moderate coronary artery lesions. IL-10 could be used for early risk assessment of long-term prognosis.
