研究了15 Me V/u197Au+197Au体系三裂变反应过程中体系的集体运动动能、核-核相互作用势、集体运动总动能以及核子激发能的演化过程,并讨论了该反应过程的能量耗散问题。通过与两裂变时体系总动能εtot和Θc.m.关联图作对比,初步得出三...研究了15 Me V/u197Au+197Au体系三裂变反应过程中体系的集体运动动能、核-核相互作用势、集体运动总动能以及核子激发能的演化过程,并讨论了该反应过程的能量耗散问题。通过与两裂变时体系总动能εtot和Θc.m.关联图作对比,初步得出三裂变反应体系的第一次裂变是极端深度非弹性散射过程;进一步分析了三裂变与两裂变反应体系总动能与碰撞参数的关系,发现小碰撞参数下两裂变比三裂变反应耗散的能量多大约150 Me V,大碰撞参数下三裂变比两裂变反应多消耗300 Me V。展开更多
n the research on the mechanical properties of the blood vessel, it is necessary to measure three-dimensional deformation of the blood vessel. This paper presents a non-contact optical method for measuring these defor...n the research on the mechanical properties of the blood vessel, it is necessary to measure three-dimensional deformation of the blood vessel. This paper presents a non-contact optical method for measuring these deformation in vitro or in vivo, and the data-processing procedure for the three-dimensional coordinate reconstruction of the aorta surface. The accuracy of this method is tested with a known cylinder. This method has been used in the study of the rabbit aorta and the result shows that it is valuable in the research on the mechanical properties of the blood vessel.展开更多
A series of true-triaxial compression tests were performed on red sandstone cubic specimens with a circular hole to investigate the influence of depth on induced spalling in tunnels.The failure process of the hole sid...A series of true-triaxial compression tests were performed on red sandstone cubic specimens with a circular hole to investigate the influence of depth on induced spalling in tunnels.The failure process of the hole sidewalls was monitored and recorded in real-time by a micro-video monitoring equipment.The general failure evolution processes of the hole sidewall at different initial depths(500 m,1000 m and 1500 m)during the adjustment of vertical stress were obtained.The results show that the hole sidewall all formed spalling before resulting in strain rockburst,and ultimately forming a V-shaped notch.The far-field principal stress for the initial failure of the tunnel shows a good positive linear correlation with the depth.As the depth increases,the stress required for the initial failure of the tunnels clearly increased,the spalling became more intense;the size and mass of the rock fragments and depth and width of the V-shaped notches increased,and the range of the failure zone extends along the hole sidewall from the local area to the entire area.Therefore,as the depth increases,the support area around the tunnel should be increased accordingly to prevent spalling.展开更多
The spindle behavior and MPF activity changes in the progression of oocyte maturation were investigated and compared with cytological observation and kinase assay between gynogenetic silver crucian carp and amphimicti...The spindle behavior and MPF activity changes in the progression of oocyte maturation were investigated and compared with cytological observation and kinase assay between gynogenetic silver crucian carp and amphimictic colored crucian carp. MPF activity was measured by using histone H1 as phosphorylation substrate. There were two similar oscillatory MPF kinase activity changes during oocyte maturation in two kinds of fishes with different reproductive modes, but there existed some subtle difference between them. The subtle difference was that the first peak of MPF kinase activity was kept to a longerlasting time in the gynogenetic silver crucian carp than in the amphimictic colored crucian carp. It was suggested that the difference may be related to the spindle behavior changes, such as tripolar spindle formation and spindle rearrangement in the gynogenetic crucian carp.展开更多
The space block search technology is used to determine a connected three-dimensional fracture network in polygonal shapes,i.e.,seepage paths.After triangulation on these polygons,a finite element mesh for 3D fracture ...The space block search technology is used to determine a connected three-dimensional fracture network in polygonal shapes,i.e.,seepage paths.After triangulation on these polygons,a finite element mesh for 3D fracture network seepage is obtained.Through introduction of the generalized Darcy's law,conservative equations for both fracture surface and fracture interactions are established.Combined with the boundary condition of Signorini's type,a partial differential equation(PDE) formulation is presented for the whole domain concerned.To solve this problem efficiently,an equivalent variational inequality(VI) formulation is given.With the penalized Heaviside function,a finite element procedure for unconfined seepage problem in 3D fracture network is developed.Through an example in a homogeneous rectangular dam,validity of the algorithm is verified.The analysis of an unconfined seepage problem in a complex fracture network shows that the proposed algorithm is very applicable to complex three-dimensional problems,and is effective in describing some interesting phenomenon usually encountered in practice,such as "preferential flow".展开更多
文摘研究了15 Me V/u197Au+197Au体系三裂变反应过程中体系的集体运动动能、核-核相互作用势、集体运动总动能以及核子激发能的演化过程,并讨论了该反应过程的能量耗散问题。通过与两裂变时体系总动能εtot和Θc.m.关联图作对比,初步得出三裂变反应体系的第一次裂变是极端深度非弹性散射过程;进一步分析了三裂变与两裂变反应体系总动能与碰撞参数的关系,发现小碰撞参数下两裂变比三裂变反应耗散的能量多大约150 Me V,大碰撞参数下三裂变比两裂变反应多消耗300 Me V。
文摘n the research on the mechanical properties of the blood vessel, it is necessary to measure three-dimensional deformation of the blood vessel. This paper presents a non-contact optical method for measuring these deformation in vitro or in vivo, and the data-processing procedure for the three-dimensional coordinate reconstruction of the aorta surface. The accuracy of this method is tested with a known cylinder. This method has been used in the study of the rabbit aorta and the result shows that it is valuable in the research on the mechanical properties of the blood vessel.
基金Projects(41877272,41472269)supported by the National Natural Science Foundation of ChinaProject(2017zzts167)supported by the Fundamental Research Funds for the Central Universities,China。
文摘A series of true-triaxial compression tests were performed on red sandstone cubic specimens with a circular hole to investigate the influence of depth on induced spalling in tunnels.The failure process of the hole sidewalls was monitored and recorded in real-time by a micro-video monitoring equipment.The general failure evolution processes of the hole sidewall at different initial depths(500 m,1000 m and 1500 m)during the adjustment of vertical stress were obtained.The results show that the hole sidewall all formed spalling before resulting in strain rockburst,and ultimately forming a V-shaped notch.The far-field principal stress for the initial failure of the tunnel shows a good positive linear correlation with the depth.As the depth increases,the stress required for the initial failure of the tunnels clearly increased,the spalling became more intense;the size and mass of the rock fragments and depth and width of the V-shaped notches increased,and the range of the failure zone extends along the hole sidewall from the local area to the entire area.Therefore,as the depth increases,the support area around the tunnel should be increased accordingly to prevent spalling.
文摘The spindle behavior and MPF activity changes in the progression of oocyte maturation were investigated and compared with cytological observation and kinase assay between gynogenetic silver crucian carp and amphimictic colored crucian carp. MPF activity was measured by using histone H1 as phosphorylation substrate. There were two similar oscillatory MPF kinase activity changes during oocyte maturation in two kinds of fishes with different reproductive modes, but there existed some subtle difference between them. The subtle difference was that the first peak of MPF kinase activity was kept to a longerlasting time in the gynogenetic silver crucian carp than in the amphimictic colored crucian carp. It was suggested that the difference may be related to the spindle behavior changes, such as tripolar spindle formation and spindle rearrangement in the gynogenetic crucian carp.
基金supported by the National Natural Science Foundation of China(Grant No.51079110)the National Basic Research Program of China("973"Project)(Grant No.2011CB013506)
文摘The space block search technology is used to determine a connected three-dimensional fracture network in polygonal shapes,i.e.,seepage paths.After triangulation on these polygons,a finite element mesh for 3D fracture network seepage is obtained.Through introduction of the generalized Darcy's law,conservative equations for both fracture surface and fracture interactions are established.Combined with the boundary condition of Signorini's type,a partial differential equation(PDE) formulation is presented for the whole domain concerned.To solve this problem efficiently,an equivalent variational inequality(VI) formulation is given.With the penalized Heaviside function,a finite element procedure for unconfined seepage problem in 3D fracture network is developed.Through an example in a homogeneous rectangular dam,validity of the algorithm is verified.The analysis of an unconfined seepage problem in a complex fracture network shows that the proposed algorithm is very applicable to complex three-dimensional problems,and is effective in describing some interesting phenomenon usually encountered in practice,such as "preferential flow".
