The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering (EPS) system. Bad tracking performance will cause assistant torque delay, and make road ...The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering (EPS) system. Bad tracking performance will cause assistant torque delay, and make road feeling bad, and is influenced by the input steering torque and system measuring noise. However the existing methods have some shortages on system's robust dynamic performance and robust stability. The mixed H2/H∞ strategy for recirculating ball-type EPS system in a pure electric bus is proposed, and vehicle dynamic model of the system is established. Due to the existence of system model uncertainty, disturbance signals, sensor noises and the demand of system dynamic performance, the indexes of robust performance and road feeling for drivers are defined as the appraisal control objectives. The H∞ method is introduced to design the H∞ controller, and the H2 method is applied to optimize the H∞ controller, thus the mixed H2/H∞ controller is designed. The response of EPS system to the motor current command with amplitude of 20 A, the road disturbance with amplitude of 500 N and the sensor random noise with the amplitude of 1 A is simulated. The simulation results show that the recirculating ball-type EPS system with the mixed H2/H∞ controller can attenuate the random noises and disturbances and track the boost curve well, so the mixed H2/H∞ controller can improve the system's robust performance and dynamic performance. For the purpose of verifying the performance of the designed control strategy, the motor current tracking performance ground tests are conducted with step response input of the steering wheel, double-lane steering test and lemniscate steering test, respectively. The tests show that the mixed H2/H∞ controller for the recirculating ball-type EPS system of pure electric bus is feasible. The designed controller can solve the robust performance and robust stability of the system, thus improve the tracking performance of the EPS system and provide satisfied road feeling for the drivers.展开更多
For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mi...For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mixed H_2/H_∞ state feedback attitude control problem of microsatellite based on extended LMI method.Firstly,the microsatellite attitude control system is established and transformed into corresponding state space form.Then,without the equivalence restriction of the two Lyapunov variables of H_2 and H∞performance,this paper introduces additional variables to design the mixed H_2/H_∞ control method based on LMI which can also reduce the conservatives.Finally,numerical simulations are analyzed to show that the proposed method can make the satellite stable within 20 s whether there is additive perturbation of the controller gain or not.The comparative analysis of the simulation results between extended LMI method and traditional LMI method also demonstrates the effectiveness and feasibility of the proposed method in this paper.展开更多
目的探讨H3.3G34W、p63及SATB2在骨巨细胞瘤(giant cell tumor of bone,GCTB)中的表达情况及其联合应用对GCTB的诊断作用和价值。方法收集西安交通大学附属红会医院病理科2020年至2022年诊断的54例GCTB、83例非骨巨细胞瘤(non-giant cel...目的探讨H3.3G34W、p63及SATB2在骨巨细胞瘤(giant cell tumor of bone,GCTB)中的表达情况及其联合应用对GCTB的诊断作用和价值。方法收集西安交通大学附属红会医院病理科2020年至2022年诊断的54例GCTB、83例非骨巨细胞瘤(non-giant cell tumor of bone,NGCTB)(包含14例动脉瘤样骨囊肿、16例软骨母细胞瘤和53例非骨化性纤维瘤)患者的样本和病历资料,采用免疫组织化学EliVision法检测H3.3G34W、p63及SATB2的表达情况。通过χ^(2)检验判断H3.3G34W、p63及SATB2的阳性率在各组间是否存在统计学差异;通过Logistic回归分析建立包括H3.3G34W、p63及SATB2的联合诊断模型,通过受试者工作特征(ROC)曲线分析评价模型的诊断价值。结果H3.3G34W、p63及SATB2在GCTB组中阳性率分别为81.5%、90.7%、92.6%;在NGCTB组中阳性率分别为2.4%、28.9%、62.7%。与NGCTB组相比,GCTB组患者年龄显著较大[(41.222±14.849)vs.(16.566±9.439);P<0.001],女性比男性患病率更高(51.9%vs.48.1%,P<0.001)。与NGCTB组相比,GCTB组中H3.3G34W(81.5%vs.2.4%,P<0.001);p63(90.7%vs.28.9%,P<0.001)和SATB2(92.6%vs.62.7%,P<0.001)的阳性率更高。单因素Logistic回归分析构建单因素预测模型,同时行ROC曲线分析,表明年龄(AUC=92.9%,P<0.001)、性别(AUC=64.5%,P=0.004)、H3.3G34W阳性率(AUC=89.5%,P<0.001)、p63阳性率(AUC=80.9%,P<0.001)、SATB2阳性率(AUC=65.0%,P=0.003)是GCTB诊断的独立预测因素。进一步的多因素Logistic回归分析构建混合预测模型,并行ROC曲线分析,发现混合模型展现出比单因素模型更好的预测价值(AUC=98.4%,P<0.001)。结论H3.3G34W、p63及SATB2是有效诊断GCTB的分子标记物,且三者联合应用更能提高GCTB的诊断预测效能。展开更多
目的研究交趾黄檀Dalbergia cochinchinensis Pierre ex Laness的新黄酮类成分及其抗H9c2心肌细胞缺氧/复氧损伤活性。方法交趾黄檀70%乙醇提取物采用硅胶、Sephadex LH-20、反相制备HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得...目的研究交趾黄檀Dalbergia cochinchinensis Pierre ex Laness的新黄酮类成分及其抗H9c2心肌细胞缺氧/复氧损伤活性。方法交趾黄檀70%乙醇提取物采用硅胶、Sephadex LH-20、反相制备HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。采用CCK-8法检测其对H9c2心肌细胞的活性及对H9c2细胞缺氧/复氧损伤的保护作用,并分析其构效关系。结果从中分离得到12个化合物,分别鉴定为阔叶黄檀酚(1)、5-O-methyllatifolin(2)、mimosifoliol(3)、5-O-methydalbergiphenol(4)、dalbergiphenol(5)、cearoin(6)、2,4-dihydroxy-5-methoxy-benzophenone(7)、2-hydroxy-4,5-dimethoxybenzophenone(8)、melannoin(9)、2,2′,5-trihydroxy-4-methoxybenzophenone(10)、黄檀素(11)、4-甲氧基黄檀醌(12)。黄檀酚及黄檀内酯类化合物对H9c2细胞毒性较小,黄檀酚类化合物抗H9c2心肌细胞缺氧/复氧损伤活性较强。结论化合物8为新天然产物,化合物4、9为首次从该植物中分离得到。黄檀酚类化合物可能是抗H9c2细胞缺氧/复氧损伤的主要新黄酮类成分。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 51005115, No. 51005248)Science Fund of State Key Laboratory of Automotive Safety and Energy of China (Grant No. KF11201)
文摘The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering (EPS) system. Bad tracking performance will cause assistant torque delay, and make road feeling bad, and is influenced by the input steering torque and system measuring noise. However the existing methods have some shortages on system's robust dynamic performance and robust stability. The mixed H2/H∞ strategy for recirculating ball-type EPS system in a pure electric bus is proposed, and vehicle dynamic model of the system is established. Due to the existence of system model uncertainty, disturbance signals, sensor noises and the demand of system dynamic performance, the indexes of robust performance and road feeling for drivers are defined as the appraisal control objectives. The H∞ method is introduced to design the H∞ controller, and the H2 method is applied to optimize the H∞ controller, thus the mixed H2/H∞ controller is designed. The response of EPS system to the motor current command with amplitude of 20 A, the road disturbance with amplitude of 500 N and the sensor random noise with the amplitude of 1 A is simulated. The simulation results show that the recirculating ball-type EPS system with the mixed H2/H∞ controller can attenuate the random noises and disturbances and track the boost curve well, so the mixed H2/H∞ controller can improve the system's robust performance and dynamic performance. For the purpose of verifying the performance of the designed control strategy, the motor current tracking performance ground tests are conducted with step response input of the steering wheel, double-lane steering test and lemniscate steering test, respectively. The tests show that the mixed H2/H∞ controller for the recirculating ball-type EPS system of pure electric bus is feasible. The designed controller can solve the robust performance and robust stability of the system, thus improve the tracking performance of the EPS system and provide satisfied road feeling for the drivers.
文摘For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mixed H_2/H_∞ state feedback attitude control problem of microsatellite based on extended LMI method.Firstly,the microsatellite attitude control system is established and transformed into corresponding state space form.Then,without the equivalence restriction of the two Lyapunov variables of H_2 and H∞performance,this paper introduces additional variables to design the mixed H_2/H_∞ control method based on LMI which can also reduce the conservatives.Finally,numerical simulations are analyzed to show that the proposed method can make the satellite stable within 20 s whether there is additive perturbation of the controller gain or not.The comparative analysis of the simulation results between extended LMI method and traditional LMI method also demonstrates the effectiveness and feasibility of the proposed method in this paper.
文摘目的探讨H3.3G34W、p63及SATB2在骨巨细胞瘤(giant cell tumor of bone,GCTB)中的表达情况及其联合应用对GCTB的诊断作用和价值。方法收集西安交通大学附属红会医院病理科2020年至2022年诊断的54例GCTB、83例非骨巨细胞瘤(non-giant cell tumor of bone,NGCTB)(包含14例动脉瘤样骨囊肿、16例软骨母细胞瘤和53例非骨化性纤维瘤)患者的样本和病历资料,采用免疫组织化学EliVision法检测H3.3G34W、p63及SATB2的表达情况。通过χ^(2)检验判断H3.3G34W、p63及SATB2的阳性率在各组间是否存在统计学差异;通过Logistic回归分析建立包括H3.3G34W、p63及SATB2的联合诊断模型,通过受试者工作特征(ROC)曲线分析评价模型的诊断价值。结果H3.3G34W、p63及SATB2在GCTB组中阳性率分别为81.5%、90.7%、92.6%;在NGCTB组中阳性率分别为2.4%、28.9%、62.7%。与NGCTB组相比,GCTB组患者年龄显著较大[(41.222±14.849)vs.(16.566±9.439);P<0.001],女性比男性患病率更高(51.9%vs.48.1%,P<0.001)。与NGCTB组相比,GCTB组中H3.3G34W(81.5%vs.2.4%,P<0.001);p63(90.7%vs.28.9%,P<0.001)和SATB2(92.6%vs.62.7%,P<0.001)的阳性率更高。单因素Logistic回归分析构建单因素预测模型,同时行ROC曲线分析,表明年龄(AUC=92.9%,P<0.001)、性别(AUC=64.5%,P=0.004)、H3.3G34W阳性率(AUC=89.5%,P<0.001)、p63阳性率(AUC=80.9%,P<0.001)、SATB2阳性率(AUC=65.0%,P=0.003)是GCTB诊断的独立预测因素。进一步的多因素Logistic回归分析构建混合预测模型,并行ROC曲线分析,发现混合模型展现出比单因素模型更好的预测价值(AUC=98.4%,P<0.001)。结论H3.3G34W、p63及SATB2是有效诊断GCTB的分子标记物,且三者联合应用更能提高GCTB的诊断预测效能。
文摘目的研究交趾黄檀Dalbergia cochinchinensis Pierre ex Laness的新黄酮类成分及其抗H9c2心肌细胞缺氧/复氧损伤活性。方法交趾黄檀70%乙醇提取物采用硅胶、Sephadex LH-20、反相制备HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。采用CCK-8法检测其对H9c2心肌细胞的活性及对H9c2细胞缺氧/复氧损伤的保护作用,并分析其构效关系。结果从中分离得到12个化合物,分别鉴定为阔叶黄檀酚(1)、5-O-methyllatifolin(2)、mimosifoliol(3)、5-O-methydalbergiphenol(4)、dalbergiphenol(5)、cearoin(6)、2,4-dihydroxy-5-methoxy-benzophenone(7)、2-hydroxy-4,5-dimethoxybenzophenone(8)、melannoin(9)、2,2′,5-trihydroxy-4-methoxybenzophenone(10)、黄檀素(11)、4-甲氧基黄檀醌(12)。黄檀酚及黄檀内酯类化合物对H9c2细胞毒性较小,黄檀酚类化合物抗H9c2心肌细胞缺氧/复氧损伤活性较强。结论化合物8为新天然产物,化合物4、9为首次从该植物中分离得到。黄檀酚类化合物可能是抗H9c2细胞缺氧/复氧损伤的主要新黄酮类成分。