传统多微网系统的集中式优化策略计算时间长,而以交替方向乘子法(alternating direction method of muitipiers,ADMM)为代表的分布式优化算法求解效率取决于目标函数的拉格朗日增广函数的求解难度,很难适用于复杂多微网系统。针对该问题...传统多微网系统的集中式优化策略计算时间长,而以交替方向乘子法(alternating direction method of muitipiers,ADMM)为代表的分布式优化算法求解效率取决于目标函数的拉格朗日增广函数的求解难度,很难适用于复杂多微网系统。针对该问题,提出了一种基于非精确广义不定邻近交替方向乘子法(the inexact generalized ADMM with indefinite proximal term,IGADMM-IPT)的多微网系统分布式协调优化方案。首先,构建多微网系统的分层优化架构和各可调节设备动态模型;然后,基于可再生能源出力、负荷需求的差值和可调节设备出力阈值确定各微网可共享发电量和储能容量;接着,基于多微网系统运行成本最低构建全局共享目标函数,利用IGADMM-IPT对该优化问题迭代求解;最后,在8个微网和一个直连设备群通过公共母线互联的场景进行仿真。结果显示,在一天内利用IGADMM-IPT获取多微网系统运行成本最低优化方案所需时间比ADMM少21.38%。展开更多
Background Early and accurate assessment of right ventricular changes in patients with Chronic obstructive pulmonary disease(COPD)is of great value,because these changes are important factors affecting the prognosis o...Background Early and accurate assessment of right ventricular changes in patients with Chronic obstructive pulmonary disease(COPD)is of great value,because these changes are important factors affecting the prognosis of patients with COPD. This study aimed to investigate the changes of right ventricular structure and function by electrocardiography in COPD patients,and to evaluate the correlations of pulmonary function,COPD assessment test(CAT)score with the changes. Methods According to the"ABCD"2016 Global initiative for chronic obstructive pulmonary disease(GOLD)update,stable COPD patients were divided into four groups:GOLD A group,GOLD B group,GOLD C group,and GOLD D group. There were 30 patients of each group enrolled from December 2016 to December 2017 in Guangdong General Hospital. During the same period,30 physical examination volunteers were enrolled as the healthy control group. Pulmonary function and echocardiography were performed in all subjects. All COPD patients completed CAT test. One-way ANOVA and SNK-q test were used to analyze the differences in parameters of right ventricular structure and function between different GOLD groups and healthy controls. Pearson correlation analysis was used to analyze the relation between CAT score,forced expiratory volume in one second(FEV1)and echocardiographic parameters. Results Compared with control group,right ventricular wall thickness(RVWT)was significantly thicker in patients of GOLD A,B and C groups(P<0.001),but not for GOLD D group. In sharp contrast,only in the patients of GOLD D group,right ventricular basal diameter(RV basal diameter)and right ventricular outflow tract(RVOT)(2.84±0.56 cm and 4.63±0.54 cm)were significantly longer than those in healthy controls and other GOLD groups(P<0.001).The patients of GOLD C and D groups had higher E/A ratio and E/e′ ratio compared with control group,GOLD A and B groups(P<0.001). But only in GOLD D group,the fractional area change(FAC)and tricuspid annular plane systolic excursion(TAPSE)were decreased significantly,compared with control group and other GOLD groups(P<0.001). The right ventricular index of myocardial performance(RIMP)in GOLD B,C and D groups was increased significantly compared with healthy control and GOLD A group(P<0.001). Moreover,correlation analysis showed that no correlations were found between FEV1 and all parameters of right ventricular structure and function,but CAT was positively correlated with RIMP(r=0.696,P=0.019). Conclusions Echocardiography could be a good assessment for right ventricular structure and function in COPD patients. Right ventricular wall thickening and diastolic dysfunction occur in the early stage of COPD,followed by right ventricular volume enlargement and systolic dysfunction.展开更多
Background Transcatheter aortic valve implantation(TAVI)has been confirmed to improve the prognosis of high-risk patients with severe aortic stenosis(AS),still little is known about changes in left ventricular(LV)morp...Background Transcatheter aortic valve implantation(TAVI)has been confirmed to improve the prognosis of high-risk patients with severe aortic stenosis(AS),still little is known about changes in left ventricular(LV)morphology and function after TAVI beyond 12 months.This study evaluated the effect of TAVI on LV morphological and functional adaptation in patients with severe AS 12 months after implantation.Methods AS patients with TAVI were selected from January 2018 to December 2020 in our hospital.Transthoracic echocardiography was performed before and 12 months after TAVI to determine LV morphology and LV function.Morphological parameters,such as left ventricular end-diastolic(LVDd)dimension,left ventricular end-systolic(LVDs)dimension,interventricular septum thickness(IVST),posterior wall thicknesses(PWT),left ventricular mass(LVM),and left ventricular mass index(LVMI)were included.Left ventricular ejection fraction(LVEF)and Tissue Doppler imaging(TDI)-derived peak systolic myocardial velocity(S′)were recorded to assess LV function.Results A total of 58 consecutive patients with severe AS who underwent TAVI were included.In all subjects,TAVI remarkably reduced peak transaortic velocity(4.6±0.6 m/s at baseline vs.2.0±0.5 m/s after TAVI,P<0.001)and mean transaortic gradient(51±15.8 mmHg at baseline vs.5.3±3.6 mmHg after TAVI,P<0.001),and improved aortic valve area(AVA)significantly(0.7±0.2 cm^(2) at baseline vs.1.8±0.4 cm^(2) after TAVI,P<0.001).IVST regressed from 14.1±8.2 mm to 12.5±3.1 mm and PWT from 13.3±7.1 mm to 10.8±2.9 mm(P<0.05).LV mass and LV mass index decreased from 316±98 g to 219±62 g(P<0.001)and from 182±46 g/m^(2) to 118±28 g/m^(2)(P<0.001),respectively.There was a statistically significant improvement in LV function(LVEF:50.6%±11.3%at baseline vs.65.1%±7.6%after TAVI;S′:3.4±1.3 cm/s at baseline vs.4.5±1.4 cm/s after TAVI,P<0.05).However,LVDd(45.2±10.6 mm at baseline vs.49.1±5.5 mm after TAVI,P=0.235)and LVDs(30.4±12.3 mm at baseline vs.34.6±4.3 mm after TAVI,P=0.346)did not change remarkably.Conclusions Significant LV function improvement and LV hypertrophy regression were found in patients with severe AS 12 months after TAVI.These changes suggested that TAVI can reverse LV remodeling.展开更多
The feldspar-based microwave dielectric ceramic with low relative permittivity(εr)and excellent mechanical properties has attracted much attention in the fifth-generation wireless communication technology.In this wor...The feldspar-based microwave dielectric ceramic with low relative permittivity(εr)and excellent mechanical properties has attracted much attention in the fifth-generation wireless communication technology.In this work,a series of microwave dielectric ceramic SrAl_(2-x)Ga_(x)Si_(2)O_(8)(0.1≤x≤2.0)was synthesized using the traditional solid-state method.X-ray diffraction pattern indicates that Ga^(3+)can be dissolved into Al^(3+),forming a solid solution.Meanwhile,substitution of Ga^(3+)for Al^(3+)can promote the space group transition from I2/c(0.1≤x≤1.4)to P21/a(1.6≤x≤2.0)with coefficient of thermal expansion(CTE)increasing from 2.9×10^(-6)℃^(-1) to 5.2×10^(-6)℃^(-1).During this substitution,the phase transition can significantly improve the structural symmetry to enhance the dielectric properties and mechanical properties.Rietveld refinement results indicate that Ga^(3+)averagely occupied four Al^(3+)compositions to form solid solution.All ceramics have a dense microstructure and high relative density above 95%.An ultralower of 5.8 was obtained at x=1.6 composition with high quality factor(Q´f)of 50700 GHz and negative temperature coefficients of resonant frequency(tf)of approximately−35×10^(-6)℃^(-1).The densification temperature can be reduced to 940℃by adding 4%(in mass)LiF,resulting in good chemical compatibility with Ag electrode.Meanwhile,negativetf can be tuned to near-zero(+3.7×10^(-6)℃^(-1))by adding CaTiO_(3) ceramic.展开更多
文摘传统多微网系统的集中式优化策略计算时间长,而以交替方向乘子法(alternating direction method of muitipiers,ADMM)为代表的分布式优化算法求解效率取决于目标函数的拉格朗日增广函数的求解难度,很难适用于复杂多微网系统。针对该问题,提出了一种基于非精确广义不定邻近交替方向乘子法(the inexact generalized ADMM with indefinite proximal term,IGADMM-IPT)的多微网系统分布式协调优化方案。首先,构建多微网系统的分层优化架构和各可调节设备动态模型;然后,基于可再生能源出力、负荷需求的差值和可调节设备出力阈值确定各微网可共享发电量和储能容量;接着,基于多微网系统运行成本最低构建全局共享目标函数,利用IGADMM-IPT对该优化问题迭代求解;最后,在8个微网和一个直连设备群通过公共母线互联的场景进行仿真。结果显示,在一天内利用IGADMM-IPT获取多微网系统运行成本最低优化方案所需时间比ADMM少21.38%。
基金supported by the National Nature Science Fund(No.81300034)
文摘Background Early and accurate assessment of right ventricular changes in patients with Chronic obstructive pulmonary disease(COPD)is of great value,because these changes are important factors affecting the prognosis of patients with COPD. This study aimed to investigate the changes of right ventricular structure and function by electrocardiography in COPD patients,and to evaluate the correlations of pulmonary function,COPD assessment test(CAT)score with the changes. Methods According to the"ABCD"2016 Global initiative for chronic obstructive pulmonary disease(GOLD)update,stable COPD patients were divided into four groups:GOLD A group,GOLD B group,GOLD C group,and GOLD D group. There were 30 patients of each group enrolled from December 2016 to December 2017 in Guangdong General Hospital. During the same period,30 physical examination volunteers were enrolled as the healthy control group. Pulmonary function and echocardiography were performed in all subjects. All COPD patients completed CAT test. One-way ANOVA and SNK-q test were used to analyze the differences in parameters of right ventricular structure and function between different GOLD groups and healthy controls. Pearson correlation analysis was used to analyze the relation between CAT score,forced expiratory volume in one second(FEV1)and echocardiographic parameters. Results Compared with control group,right ventricular wall thickness(RVWT)was significantly thicker in patients of GOLD A,B and C groups(P<0.001),but not for GOLD D group. In sharp contrast,only in the patients of GOLD D group,right ventricular basal diameter(RV basal diameter)and right ventricular outflow tract(RVOT)(2.84±0.56 cm and 4.63±0.54 cm)were significantly longer than those in healthy controls and other GOLD groups(P<0.001).The patients of GOLD C and D groups had higher E/A ratio and E/e′ ratio compared with control group,GOLD A and B groups(P<0.001). But only in GOLD D group,the fractional area change(FAC)and tricuspid annular plane systolic excursion(TAPSE)were decreased significantly,compared with control group and other GOLD groups(P<0.001). The right ventricular index of myocardial performance(RIMP)in GOLD B,C and D groups was increased significantly compared with healthy control and GOLD A group(P<0.001). Moreover,correlation analysis showed that no correlations were found between FEV1 and all parameters of right ventricular structure and function,but CAT was positively correlated with RIMP(r=0.696,P=0.019). Conclusions Echocardiography could be a good assessment for right ventricular structure and function in COPD patients. Right ventricular wall thickening and diastolic dysfunction occur in the early stage of COPD,followed by right ventricular volume enlargement and systolic dysfunction.
基金supported by the Guangdong Medical Research Foundation(No.A2019182)。
文摘Background Transcatheter aortic valve implantation(TAVI)has been confirmed to improve the prognosis of high-risk patients with severe aortic stenosis(AS),still little is known about changes in left ventricular(LV)morphology and function after TAVI beyond 12 months.This study evaluated the effect of TAVI on LV morphological and functional adaptation in patients with severe AS 12 months after implantation.Methods AS patients with TAVI were selected from January 2018 to December 2020 in our hospital.Transthoracic echocardiography was performed before and 12 months after TAVI to determine LV morphology and LV function.Morphological parameters,such as left ventricular end-diastolic(LVDd)dimension,left ventricular end-systolic(LVDs)dimension,interventricular septum thickness(IVST),posterior wall thicknesses(PWT),left ventricular mass(LVM),and left ventricular mass index(LVMI)were included.Left ventricular ejection fraction(LVEF)and Tissue Doppler imaging(TDI)-derived peak systolic myocardial velocity(S′)were recorded to assess LV function.Results A total of 58 consecutive patients with severe AS who underwent TAVI were included.In all subjects,TAVI remarkably reduced peak transaortic velocity(4.6±0.6 m/s at baseline vs.2.0±0.5 m/s after TAVI,P<0.001)and mean transaortic gradient(51±15.8 mmHg at baseline vs.5.3±3.6 mmHg after TAVI,P<0.001),and improved aortic valve area(AVA)significantly(0.7±0.2 cm^(2) at baseline vs.1.8±0.4 cm^(2) after TAVI,P<0.001).IVST regressed from 14.1±8.2 mm to 12.5±3.1 mm and PWT from 13.3±7.1 mm to 10.8±2.9 mm(P<0.05).LV mass and LV mass index decreased from 316±98 g to 219±62 g(P<0.001)and from 182±46 g/m^(2) to 118±28 g/m^(2)(P<0.001),respectively.There was a statistically significant improvement in LV function(LVEF:50.6%±11.3%at baseline vs.65.1%±7.6%after TAVI;S′:3.4±1.3 cm/s at baseline vs.4.5±1.4 cm/s after TAVI,P<0.05).However,LVDd(45.2±10.6 mm at baseline vs.49.1±5.5 mm after TAVI,P=0.235)and LVDs(30.4±12.3 mm at baseline vs.34.6±4.3 mm after TAVI,P=0.346)did not change remarkably.Conclusions Significant LV function improvement and LV hypertrophy regression were found in patients with severe AS 12 months after TAVI.These changes suggested that TAVI can reverse LV remodeling.
基金National Natural Science Foundation of China (52302140)Major Scientific and Technological Innovation Project of Wenzhou (ZG2023040, ZG2023042)Joint Funds of the National Natural Science Foundation of China Key Program (U21B2068)。
文摘The feldspar-based microwave dielectric ceramic with low relative permittivity(εr)and excellent mechanical properties has attracted much attention in the fifth-generation wireless communication technology.In this work,a series of microwave dielectric ceramic SrAl_(2-x)Ga_(x)Si_(2)O_(8)(0.1≤x≤2.0)was synthesized using the traditional solid-state method.X-ray diffraction pattern indicates that Ga^(3+)can be dissolved into Al^(3+),forming a solid solution.Meanwhile,substitution of Ga^(3+)for Al^(3+)can promote the space group transition from I2/c(0.1≤x≤1.4)to P21/a(1.6≤x≤2.0)with coefficient of thermal expansion(CTE)increasing from 2.9×10^(-6)℃^(-1) to 5.2×10^(-6)℃^(-1).During this substitution,the phase transition can significantly improve the structural symmetry to enhance the dielectric properties and mechanical properties.Rietveld refinement results indicate that Ga^(3+)averagely occupied four Al^(3+)compositions to form solid solution.All ceramics have a dense microstructure and high relative density above 95%.An ultralower of 5.8 was obtained at x=1.6 composition with high quality factor(Q´f)of 50700 GHz and negative temperature coefficients of resonant frequency(tf)of approximately−35×10^(-6)℃^(-1).The densification temperature can be reduced to 940℃by adding 4%(in mass)LiF,resulting in good chemical compatibility with Ag electrode.Meanwhile,negativetf can be tuned to near-zero(+3.7×10^(-6)℃^(-1))by adding CaTiO_(3) ceramic.
