The phylogenetic origin of Beckmannia remains unknown. The genus has been placed within the Chlorideae, Aveneae （Agrostideae）, Poeae, or treated as an isolate lineage, Beckmanniinae. In the present study, we used nu...The phylogenetic origin of Beckmannia remains unknown. The genus has been placed within the Chlorideae, Aveneae （Agrostideae）, Poeae, or treated as an isolate lineage, Beckmanniinae. In the present study, we used nuclear internal transcribed spacer （ITS） and chloroplast trnL-F sequences to examine the phylogenetic relationship between Beckmannia and those genera that have assumed to be related. On the basis of the results of our studies, the following conclusions could be drawn： （i） Beckmannia and Alopecurus are sister groups with high support; and （ii） Beckmannia and Alopecurus are nested in the Poeae clade with high support. The results of our analysis suggest that Beckmannia should be placed in Poeae.展开更多
The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China.An Eulerian two-phase model in the computational flu...The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China.An Eulerian two-phase model in the computational fluid dynamic (CFD) software FLUENT,validated with published data,was used to solve the gas-solid multiphase flow of a sandstorm around a train.The train aerodynamic performance under different sandstorm levels and no sand conditions was then simulated.Results showed that in sandstorm weather,the drag,lift,side forces and overturning moment increase by variable degrees.Based on a numerical analysis of aerodynamic characteristics,an equation of train stability was also derived using the theory of moment balance from the view of dynamics.A recommended speed limit of a train under different sandstorm levels was calculated based on the stability analysis.展开更多
In this paper,we consider the existence and uniqueness of the mild solutions for a class of fractional non-autonomous evolution equations with delay and Caputo's fractional derivatives.By using the measure of nonc...In this paper,we consider the existence and uniqueness of the mild solutions for a class of fractional non-autonomous evolution equations with delay and Caputo's fractional derivatives.By using the measure of noncompactness,β-resolvent family,fixed point theorems and Banach contraction mapping principle,we improve and generalizes some related results on this topic.At last,we give an example to illustrate the application of the main results of this paper.展开更多
基金supported b ythe National Natural Science Foundation of China(30270107)the Project Sponsored by the Scientific Research Foundation for the Doctors,Weifang Medical University
文摘The phylogenetic origin of Beckmannia remains unknown. The genus has been placed within the Chlorideae, Aveneae （Agrostideae）, Poeae, or treated as an isolate lineage, Beckmanniinae. In the present study, we used nuclear internal transcribed spacer （ITS） and chloroplast trnL-F sequences to examine the phylogenetic relationship between Beckmannia and those genera that have assumed to be related. On the basis of the results of our studies, the following conclusions could be drawn： （i） Beckmannia and Alopecurus are sister groups with high support; and （ii） Beckmannia and Alopecurus are nested in the Poeae clade with high support. The results of our analysis suggest that Beckmannia should be placed in Poeae.
基金Project(No.2009BAG12A01-C03) supported by the National Key Technology R&D Program of China
文摘The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China.An Eulerian two-phase model in the computational fluid dynamic (CFD) software FLUENT,validated with published data,was used to solve the gas-solid multiphase flow of a sandstorm around a train.The train aerodynamic performance under different sandstorm levels and no sand conditions was then simulated.Results showed that in sandstorm weather,the drag,lift,side forces and overturning moment increase by variable degrees.Based on a numerical analysis of aerodynamic characteristics,an equation of train stability was also derived using the theory of moment balance from the view of dynamics.A recommended speed limit of a train under different sandstorm levels was calculated based on the stability analysis.
基金The paper is supported financially by the Project of Shandong Province Higher Educational Science and Technology Program(J16LI14)the National Natural Science Foundation of China(No.11871302)+2 种基金the Taishan Scholars Program of Shandong Province(No.tsqn20161041)the Humanities and Social Sciences Project of the Ministry Education of China(No.19YJA910002)the Natural Science Foundation of Shandong Province(No.ZR2018MG002).
文摘In this paper,we consider the existence and uniqueness of the mild solutions for a class of fractional non-autonomous evolution equations with delay and Caputo's fractional derivatives.By using the measure of noncompactness,β-resolvent family,fixed point theorems and Banach contraction mapping principle,we improve and generalizes some related results on this topic.At last,we give an example to illustrate the application of the main results of this paper.
