The characteristic wind curve （CWC） was com- monly used in the previous work to evaluate the operational safety of the high-speed trains exposed to crosswinds. How- ever, the CWC only provide the dividing line betwe...The characteristic wind curve （CWC） was com- monly used in the previous work to evaluate the operational safety of the high-speed trains exposed to crosswinds. How- ever, the CWC only provide the dividing line between safety state and failure state of high-speed trains, which can not evaluate the risk of derailment of high-speed trains when ex- posed to natural winds. In the present paper, a more realistic approach taking into account the stochastic characteristics of natural winds is proposed, which can give a reasonable and effective assessment of the operational safety of high-speed trains under stochastic winds. In this approach, the longitudi- nal and lateral components of stochastic winds are simulated based on the Cooper theory and harmonic superposition. An algorithm is set up for calculating the unsteady aerody- namic forces （moments） of the high-speed trains exposed to stochastic winds. A multi-body dynamic model of the rail vehicle is established to compute the vehicle system dynamic response subjected to the unsteady aerodynamic forces （mo- ments） input. Then the statistical method is used to get the mean characteristic wind curve （MCWC） and spread range of the high-speed trains exposed to stochastic winds. It is found that the CWC provided by the previous analyticalmethod produces over-conservative limits. The methodol- ogy proposed in the present paper can provide more signif- icant reference for the safety operation of high-speed trains exposed to stochastic winds.展开更多
两性霉素B为多烯类抗真菌抗生素,可通过影响细胞膜通透性发挥抑制真菌生长的作用,被广泛用于治疗引起患者免疫缺陷的全身真菌感染性疾病。其药理作用对生物膜性质的影响一直是一个关注热点。作者利用Langmuir-Blodgett膜技术和原子力显...两性霉素B为多烯类抗真菌抗生素,可通过影响细胞膜通透性发挥抑制真菌生长的作用,被广泛用于治疗引起患者免疫缺陷的全身真菌感染性疾病。其药理作用对生物膜性质的影响一直是一个关注热点。作者利用Langmuir-Blodgett膜技术和原子力显微镜(atomic force microscope,AFM)分别研究了鞘磷脂/两性霉素B二元混合单层膜及鞘磷脂、胆固醇和两性霉素B三元混合单层膜体系的热力学特性和表面形貌。通过对二元混合系统和三元混合系统的表面压力-平均分子面积曲线的测量,定量分析了固定膜压下的平均分子面积、过量分子面积和过量吉布斯自由能等参量,并分别观测了二元混合单层膜和三元混合单层膜的形态。热力学分析结果表明,胆固醇的加入可以促进鞘磷脂/两性霉素分子之间的相互作用,同时,AFM观察结果表明,一定量的胆固醇可以提高混合单层膜的平整度和稳定性。展开更多
基金supported by the 2013 Doctoral Innovation Funds of Southwest Jiaotong University and the Fundamental Research Funds for the Central Universitiesthe High-speed Railway Basic Research Fund Key Project of China(U1234208)the National Natural Science Foundation of China(50823004)
文摘The characteristic wind curve （CWC） was com- monly used in the previous work to evaluate the operational safety of the high-speed trains exposed to crosswinds. How- ever, the CWC only provide the dividing line between safety state and failure state of high-speed trains, which can not evaluate the risk of derailment of high-speed trains when ex- posed to natural winds. In the present paper, a more realistic approach taking into account the stochastic characteristics of natural winds is proposed, which can give a reasonable and effective assessment of the operational safety of high-speed trains under stochastic winds. In this approach, the longitudi- nal and lateral components of stochastic winds are simulated based on the Cooper theory and harmonic superposition. An algorithm is set up for calculating the unsteady aerody- namic forces （moments） of the high-speed trains exposed to stochastic winds. A multi-body dynamic model of the rail vehicle is established to compute the vehicle system dynamic response subjected to the unsteady aerodynamic forces （mo- ments） input. Then the statistical method is used to get the mean characteristic wind curve （MCWC） and spread range of the high-speed trains exposed to stochastic winds. It is found that the CWC provided by the previous analyticalmethod produces over-conservative limits. The methodol- ogy proposed in the present paper can provide more signif- icant reference for the safety operation of high-speed trains exposed to stochastic winds.
文摘两性霉素B为多烯类抗真菌抗生素,可通过影响细胞膜通透性发挥抑制真菌生长的作用,被广泛用于治疗引起患者免疫缺陷的全身真菌感染性疾病。其药理作用对生物膜性质的影响一直是一个关注热点。作者利用Langmuir-Blodgett膜技术和原子力显微镜(atomic force microscope,AFM)分别研究了鞘磷脂/两性霉素B二元混合单层膜及鞘磷脂、胆固醇和两性霉素B三元混合单层膜体系的热力学特性和表面形貌。通过对二元混合系统和三元混合系统的表面压力-平均分子面积曲线的测量,定量分析了固定膜压下的平均分子面积、过量分子面积和过量吉布斯自由能等参量,并分别观测了二元混合单层膜和三元混合单层膜的形态。热力学分析结果表明,胆固醇的加入可以促进鞘磷脂/两性霉素分子之间的相互作用,同时,AFM观察结果表明,一定量的胆固醇可以提高混合单层膜的平整度和稳定性。
