For the ultra HVDC(UHVDC)with the hierarchical connection mode at the inverter side,considering the change of the Thevenin equivalent parameters(TEP)of post-fault AC grid,a coordinated control strategy to the subseque...For the ultra HVDC(UHVDC)with the hierarchical connection mode at the inverter side,considering the change of the Thevenin equivalent parameters(TEP)of post-fault AC grid,a coordinated control strategy to the subsequent commutation failure(SCF)at both layers is newly proposed.The originality of this work is manifested in three aspects.1)The mechanism of the SCF at the fault layer is newly found by deriving the analytical expression of the extinction angle with the TEP,and that at the non-fault layer is newly found by the voltage-time area theory with the DC current coupling.2)An estimation model for the TEPs of two AC grids at the inverter side is proposed with the post-fault quantities.To address the random noise and inaccurate measurement data,an adaptive robust least squares method based on the median principle is proposed to solve the TEP model.3)A coordinated control strategy with the estimated TEP is proposed to compensate for the extinction angle at the fault layer and limit the DC current at the non-fault layer,thus suppressing the SCF.The simulation results verify the suppression effect of the proposed control on the SCF under different fault conditions.展开更多
Hypertrophic cardiomyopathy(HCM)is a major contributor to cardiovascular diseases(CVD),the leading cause of death globally.HCM can precipitate heart failure(HF)by causing the cardiac tissue to weaken and stretch,there...Hypertrophic cardiomyopathy(HCM)is a major contributor to cardiovascular diseases(CVD),the leading cause of death globally.HCM can precipitate heart failure(HF)by causing the cardiac tissue to weaken and stretch,thereby impairing its pumping efficiency.Moreover,HCM increases the risk of atrial fibrillation,which in turn elevates the likelihood of thrombus formation and stroke.Given these significant clinical ramifications,research into the etiology and pathogenesis of HCM is intensifying at multiple levels.In this review,we discuss and synthesize the latest findings on HCM pathogenesis,drawing on key experimental studies conducted both in vitro and in vivo.We also offer our insights and perspectives on these mechanisms,while highlighting the limitations of current research.Advancing fundamental research in this area is essential for developing effective therapeutic interventions and enhancing the clinical management of HCM.展开更多
Hypertrophic cardiomyopathy(HCM)is a primary myocardial disease characterized by myocardial hypertrophy,excluding other cardiovascular or systemic/metabolic causes of ventricular wall thickening.Apical hypertrophic ca...Hypertrophic cardiomyopathy(HCM)is a primary myocardial disease characterized by myocardial hypertrophy,excluding other cardiovascular or systemic/metabolic causes of ventricular wall thickening.Apical hypertrophic cardiomyopathy(ApHCM)represents a special form of ventricular hypertrophy predominantly affecting the left ventricular apex below the papillary muscles,typically without significant left ventricular outflow tract obstruction.[1,2]ApHCM often coexists with mild coronary artery abnormalities,[3]and reports of acute myocardial infarction with coronary artery stenosis in ApHCM or HCM patients are uncommon.展开更多
创造低噪声的乘车环境,建立减振降噪环境友好型的地铁站区环境已成为轨道交通建设的发展趋势。测试分析一种陶粒混凝土制作的新型吸音结构HCM型吸声板的降噪效果。试验在北京交通大学轨道减振与振动控制实验室中进行,将吸声板铺设在轨...创造低噪声的乘车环境,建立减振降噪环境友好型的地铁站区环境已成为轨道交通建设的发展趋势。测试分析一种陶粒混凝土制作的新型吸音结构HCM型吸声板的降噪效果。试验在北京交通大学轨道减振与振动控制实验室中进行,将吸声板铺设在轨道的钢轨之间,在道床和隧道壁上布置测点,模拟干燥、潮湿、下雨以及潮湿后干燥的工况进行试验测试。分析结果表明：不同测点和工况下,减噪效果都能达到4~5 d BA;频域分析表明,吸声板具有较宽的降噪频段。对于隧道壁测点,吸声板对250 Hz以上频段噪声的降噪效果较优;对于道床测点,吸声板对500 Hz以上频段噪声的降噪效果较好。展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 51877061.
文摘For the ultra HVDC(UHVDC)with the hierarchical connection mode at the inverter side,considering the change of the Thevenin equivalent parameters(TEP)of post-fault AC grid,a coordinated control strategy to the subsequent commutation failure(SCF)at both layers is newly proposed.The originality of this work is manifested in three aspects.1)The mechanism of the SCF at the fault layer is newly found by deriving the analytical expression of the extinction angle with the TEP,and that at the non-fault layer is newly found by the voltage-time area theory with the DC current coupling.2)An estimation model for the TEPs of two AC grids at the inverter side is proposed with the post-fault quantities.To address the random noise and inaccurate measurement data,an adaptive robust least squares method based on the median principle is proposed to solve the TEP model.3)A coordinated control strategy with the estimated TEP is proposed to compensate for the extinction angle at the fault layer and limit the DC current at the non-fault layer,thus suppressing the SCF.The simulation results verify the suppression effect of the proposed control on the SCF under different fault conditions.
基金supported by Henan Provincial Key Technologies R&D Program(Grant No.25202310242)Henan Provincial Medical Science and Technology Tackling Program(Grant No.LHGJ20240150).
文摘Hypertrophic cardiomyopathy(HCM)is a major contributor to cardiovascular diseases(CVD),the leading cause of death globally.HCM can precipitate heart failure(HF)by causing the cardiac tissue to weaken and stretch,thereby impairing its pumping efficiency.Moreover,HCM increases the risk of atrial fibrillation,which in turn elevates the likelihood of thrombus formation and stroke.Given these significant clinical ramifications,research into the etiology and pathogenesis of HCM is intensifying at multiple levels.In this review,we discuss and synthesize the latest findings on HCM pathogenesis,drawing on key experimental studies conducted both in vitro and in vivo.We also offer our insights and perspectives on these mechanisms,while highlighting the limitations of current research.Advancing fundamental research in this area is essential for developing effective therapeutic interventions and enhancing the clinical management of HCM.
文摘Hypertrophic cardiomyopathy(HCM)is a primary myocardial disease characterized by myocardial hypertrophy,excluding other cardiovascular or systemic/metabolic causes of ventricular wall thickening.Apical hypertrophic cardiomyopathy(ApHCM)represents a special form of ventricular hypertrophy predominantly affecting the left ventricular apex below the papillary muscles,typically without significant left ventricular outflow tract obstruction.[1,2]ApHCM often coexists with mild coronary artery abnormalities,[3]and reports of acute myocardial infarction with coronary artery stenosis in ApHCM or HCM patients are uncommon.
文摘创造低噪声的乘车环境,建立减振降噪环境友好型的地铁站区环境已成为轨道交通建设的发展趋势。测试分析一种陶粒混凝土制作的新型吸音结构HCM型吸声板的降噪效果。试验在北京交通大学轨道减振与振动控制实验室中进行,将吸声板铺设在轨道的钢轨之间,在道床和隧道壁上布置测点,模拟干燥、潮湿、下雨以及潮湿后干燥的工况进行试验测试。分析结果表明：不同测点和工况下,减噪效果都能达到4~5 d BA;频域分析表明,吸声板具有较宽的降噪频段。对于隧道壁测点,吸声板对250 Hz以上频段噪声的降噪效果较优;对于道床测点,吸声板对500 Hz以上频段噪声的降噪效果较好。
