In the preliminary design stage of high-speed train smart suspension,a simple,yet accurate magnetorheological(MR)damper model whose parameters have clear physical meaning is needed.Based on the working mechanism analy...In the preliminary design stage of high-speed train smart suspension,a simple,yet accurate magnetorheological(MR)damper model whose parameters have clear physical meaning is needed.Based on the working mechanism analysis and the dynamic behavior study of the MR damper,a new consecutive viscoelastic plastics(VEP)model is proposed.A methodology to find the parameters of the proposed model directly has been proposed.The comparison with experimental results indicates that the proposed model could adequately characterize the intrinsic nonlinear behavior of the MR damper,including the hysteretic behavior,roll-off phenomenon,and the variation of the hysteresis width in terms of the frequency and magnitude of excitation.The results of experimental testing prove that the accuracy of the proposed model is higher than that of the phenomenological model while only containing four undetermined parameters with clear physical meaning.Moreover,based on the proposed VEP model,a nonlinear stiffness VEP(nkVEP)model is developed with higher precision in the hysteretic region.The nkVEP model,which can reproduce the behavior of the damper with fluctuating input current,is developed.The proposed model could predict accurately the response of the MR damper in a wide range of frequency and displacement.展开更多
目的:本实验拟从土壤中分离可降解塑料的微生物,并通过分子生物学和生物信息学的方法进行初步鉴定。方法:在垃圾场表层15cm以下富含塑料的土壤采样,通过稀释不同浓度梯度进行涂布分离,然后运用选择性培养基聚乙烯醇(PVA)、聚氯乙烯(PVC...目的:本实验拟从土壤中分离可降解塑料的微生物,并通过分子生物学和生物信息学的方法进行初步鉴定。方法:在垃圾场表层15cm以下富含塑料的土壤采样,通过稀释不同浓度梯度进行涂布分离,然后运用选择性培养基聚乙烯醇(PVA)、聚氯乙烯(PVC)进行微生物分离。通过生物发酵培养的方法验证对塑料的降解作用,最后通过对18 S rDNA保守区扩增,并经过MAGA5.0软件的同源比对,对所分离的微生物进行分子鉴定。结果:从PVC、PVA选择性培养基中分离得到了3株真菌,对部分塑料制品有一定的降解作用,分子鉴定表明三株真菌菌株均属于地霉属的菌株。结论:本实验成功分离得到三株可降解塑料的真菌,为将来的微生物降解塑料应用奠定基础。展开更多
基金supported by grant from the Innovation and Technology Support Program of the Hong Kong Special Administrative Region,China(Project No.ITS/241/11)the National Natural Science Foundation of China(Grant No.61134002)the National Basic Research Program of China("973" Program)(Grant No.2011CB711106)
文摘In the preliminary design stage of high-speed train smart suspension,a simple,yet accurate magnetorheological(MR)damper model whose parameters have clear physical meaning is needed.Based on the working mechanism analysis and the dynamic behavior study of the MR damper,a new consecutive viscoelastic plastics(VEP)model is proposed.A methodology to find the parameters of the proposed model directly has been proposed.The comparison with experimental results indicates that the proposed model could adequately characterize the intrinsic nonlinear behavior of the MR damper,including the hysteretic behavior,roll-off phenomenon,and the variation of the hysteresis width in terms of the frequency and magnitude of excitation.The results of experimental testing prove that the accuracy of the proposed model is higher than that of the phenomenological model while only containing four undetermined parameters with clear physical meaning.Moreover,based on the proposed VEP model,a nonlinear stiffness VEP(nkVEP)model is developed with higher precision in the hysteretic region.The nkVEP model,which can reproduce the behavior of the damper with fluctuating input current,is developed.The proposed model could predict accurately the response of the MR damper in a wide range of frequency and displacement.
文摘目的:本实验拟从土壤中分离可降解塑料的微生物,并通过分子生物学和生物信息学的方法进行初步鉴定。方法:在垃圾场表层15cm以下富含塑料的土壤采样,通过稀释不同浓度梯度进行涂布分离,然后运用选择性培养基聚乙烯醇(PVA)、聚氯乙烯(PVC)进行微生物分离。通过生物发酵培养的方法验证对塑料的降解作用,最后通过对18 S rDNA保守区扩增,并经过MAGA5.0软件的同源比对,对所分离的微生物进行分子鉴定。结果:从PVC、PVA选择性培养基中分离得到了3株真菌,对部分塑料制品有一定的降解作用,分子鉴定表明三株真菌菌株均属于地霉属的菌株。结论:本实验成功分离得到三株可降解塑料的真菌,为将来的微生物降解塑料应用奠定基础。
