Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)...Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)control strategy based on a power outer loop and voltage-current inner loops,aiming to enhance the stability and current-limiting capability of GFM converters during grid fault conditions.During voltage sags,the GFM converter’s voltage source behavior is maintained by dynamically adjusting the reactive power reference to provide voltage support,thereby effectively suppressing the steady-state component of the fault current.To address the active power imbalance induced by voltage sags,a dynamic active power reference correction method based on apparent power is designed to mitigate power angle oscillations and limit transient current.Moreover,an adaptive virtual impedance loop is implemented to enhance dynamic transient current-limiting performance during the fault initiation phase.This approach improves the responsiveness of the inner loop and ensures safe system operation under various fault severities.Under asymmetric fault conditions,a negative-sequence reactive current compensation strategy is incorporated to further suppress negative-sequence voltage and improve voltage symmetry.The proposed control scheme enables coordinated operation of multiple control objectives,including voltage support,current suppression,and power angle stability,across different fault scenarios.Finally,MATLAB/Simulink simulation results validate the effectiveness of the proposed strategy,showcasing its superior performance in current limiting and power angle stability,thereby significantly enhancing the system’s fault ride-through capability.展开更多
This review paper examines the various types of electrical generators used to convert wave energy into electrical energy.The focus is on both linear and rotary generators,including their design principles,operational ...This review paper examines the various types of electrical generators used to convert wave energy into electrical energy.The focus is on both linear and rotary generators,including their design principles,operational efficiencies,and technological advancements.Linear generators,such as Induction,permanent magnet synchronous,and switched reluctance types,are highlighted for their direct conversion capability,eliminating the need for mechanical gearboxes.Rotary Induction generators,permanent magnet synchronous generators,and doubly-fed Induction generators are evaluated for their established engineering principles and integration with existing grid infrastructure.The paper discusses the historical development,environmental benefits,and ongoing advancements in wave energy technologies,emphasizing the increasing feasibility and scalability of wave energy as a renewable source.Through a comprehensive analysis,this review provides insights into the current state and future prospects of electrical generators in wave energy conversion,underscoring their potential to significantly reduce reliance on fossil fuels and mitigate environmental impacts.展开更多
AIM To study the role of interleukin 1β converting enzyme (ICE) in antitumor drug induced apoptosis in tumor cells. METHODS Morphological changes in human esophageal carcinoma Eca 109 cells after treated with 5 ...AIM To study the role of interleukin 1β converting enzyme (ICE) in antitumor drug induced apoptosis in tumor cells. METHODS Morphological changes in human esophageal carcinoma Eca 109 cells after treated with 5 fluorouracil (5 FU) were observed under light and electron microscope. Expression of ICE in the tumor cells exposed to 5 FU was examined by the immunocytochemical method. RESULTS The cells treated with 5 FU displayed disappearance of nucleoli, chromatin gathering under nuclear envelope, karyorrhexis, budding and the formation of apoptotic bodies. The expression of ICE was negative in control cells, and 5 FU could induce the ICE expression in Eca 109 cells undergoing apoptosis. The number and the staining intensity of positive cells increased with the extension of action time. CONCLUSION 5 FU may induce apoptosis in human esophageal carcinoma Eca 109 cells; ICE gene may be involved in the regulation of 5 FU induced apoptosis; and ICE protein may mediate apoptosis induced by 5 FU.展开更多
Angiotensin I converting enzyme （ACE） plays an important physiological role in the regulation of hypertension. In this study, we applied virtual screening to discover a novel angiotensin I converting enzyme inhibito...Angiotensin I converting enzyme （ACE） plays an important physiological role in the regulation of hypertension. In this study, we applied virtual screening to discover a novel angiotensin I converting enzyme inhibitory peptides from milk casein. One potential hit was identified based on docking scores, subsequently confirmed by activity studies in vitro （IC50=20.85 μmol L-1）. The proposed peptide in this study contains a unique sequence, Lys-Val-Leu-Ile-Leu-Ala. Moreover, we performed the docking studies to understand the binding mode between the enzyme and peptide hit.展开更多
文摘Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)control strategy based on a power outer loop and voltage-current inner loops,aiming to enhance the stability and current-limiting capability of GFM converters during grid fault conditions.During voltage sags,the GFM converter’s voltage source behavior is maintained by dynamically adjusting the reactive power reference to provide voltage support,thereby effectively suppressing the steady-state component of the fault current.To address the active power imbalance induced by voltage sags,a dynamic active power reference correction method based on apparent power is designed to mitigate power angle oscillations and limit transient current.Moreover,an adaptive virtual impedance loop is implemented to enhance dynamic transient current-limiting performance during the fault initiation phase.This approach improves the responsiveness of the inner loop and ensures safe system operation under various fault severities.Under asymmetric fault conditions,a negative-sequence reactive current compensation strategy is incorporated to further suppress negative-sequence voltage and improve voltage symmetry.The proposed control scheme enables coordinated operation of multiple control objectives,including voltage support,current suppression,and power angle stability,across different fault scenarios.Finally,MATLAB/Simulink simulation results validate the effectiveness of the proposed strategy,showcasing its superior performance in current limiting and power angle stability,thereby significantly enhancing the system’s fault ride-through capability.
文摘This review paper examines the various types of electrical generators used to convert wave energy into electrical energy.The focus is on both linear and rotary generators,including their design principles,operational efficiencies,and technological advancements.Linear generators,such as Induction,permanent magnet synchronous,and switched reluctance types,are highlighted for their direct conversion capability,eliminating the need for mechanical gearboxes.Rotary Induction generators,permanent magnet synchronous generators,and doubly-fed Induction generators are evaluated for their established engineering principles and integration with existing grid infrastructure.The paper discusses the historical development,environmental benefits,and ongoing advancements in wave energy technologies,emphasizing the increasing feasibility and scalability of wave energy as a renewable source.Through a comprehensive analysis,this review provides insights into the current state and future prospects of electrical generators in wave energy conversion,underscoring their potential to significantly reduce reliance on fossil fuels and mitigate environmental impacts.
文摘AIM To study the role of interleukin 1β converting enzyme (ICE) in antitumor drug induced apoptosis in tumor cells. METHODS Morphological changes in human esophageal carcinoma Eca 109 cells after treated with 5 fluorouracil (5 FU) were observed under light and electron microscope. Expression of ICE in the tumor cells exposed to 5 FU was examined by the immunocytochemical method. RESULTS The cells treated with 5 FU displayed disappearance of nucleoli, chromatin gathering under nuclear envelope, karyorrhexis, budding and the formation of apoptotic bodies. The expression of ICE was negative in control cells, and 5 FU could induce the ICE expression in Eca 109 cells undergoing apoptosis. The number and the staining intensity of positive cells increased with the extension of action time. CONCLUSION 5 FU may induce apoptosis in human esophageal carcinoma Eca 109 cells; ICE gene may be involved in the regulation of 5 FU induced apoptosis; and ICE protein may mediate apoptosis induced by 5 FU.
基金supported by the National High Technology Research and Development Program of China(863 Program, 2008AA10Z313)the Foundation for Sciand Tech Research Project of Zhejiang Province, China(2006C12096)Natural Science Foundation of Zhejiang Province, China (Y3090026)
文摘Angiotensin I converting enzyme （ACE） plays an important physiological role in the regulation of hypertension. In this study, we applied virtual screening to discover a novel angiotensin I converting enzyme inhibitory peptides from milk casein. One potential hit was identified based on docking scores, subsequently confirmed by activity studies in vitro （IC50=20.85 μmol L-1）. The proposed peptide in this study contains a unique sequence, Lys-Val-Leu-Ile-Leu-Ala. Moreover, we performed the docking studies to understand the binding mode between the enzyme and peptide hit.
