Pipeline spans may occur due to natural seabed irregularities or local scour of bed sediment. The pure in-line（IL）vortex-induced vibrations（VIV） analysis of the free spans is an important subject for design of pip...Pipeline spans may occur due to natural seabed irregularities or local scour of bed sediment. The pure in-line（IL）vortex-induced vibrations（VIV） analysis of the free spans is an important subject for design of pipeline in uneven seabed. The main objective of this paper is to analyze the characteristics of pure IL VIV of a free spanning pipeline under general boundary conditions. An IL wake oscillator model which can describe the coupling of pipeline structure and fluctuating drag is introduced and employed. The coupled partial differential equations of structure and wake are transformed into a set of ordinary differential equations using two-mode Galerkin method. Some case studies are presented and thoroughly discussed in order to investigate the effects of internal fluid, axial force and boundary conditions on the pure IL VIV.展开更多
The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium de...The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium depth distribution from the front surface to 500 nm depth was found.The results indicate that an equilibrium deuterium distribution region from the front surface to a depth approximately equal to the mean range of implanted deuterons was formed in Yb during the implantation.The deduced deuterium concentration in the equilibrium deuterium distribution region was D/Yb = 22%.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51479135,51525803 and51679167)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51321065)the Major State Basic Research Development Program of China(973 Program,Grant No.2014CB046801)
文摘Pipeline spans may occur due to natural seabed irregularities or local scour of bed sediment. The pure in-line（IL）vortex-induced vibrations（VIV） analysis of the free spans is an important subject for design of pipeline in uneven seabed. The main objective of this paper is to analyze the characteristics of pure IL VIV of a free spanning pipeline under general boundary conditions. An IL wake oscillator model which can describe the coupling of pipeline structure and fluctuating drag is introduced and employed. The coupled partial differential equations of structure and wake are transformed into a set of ordinary differential equations using two-mode Galerkin method. Some case studies are presented and thoroughly discussed in order to investigate the effects of internal fluid, axial force and boundary conditions on the pure IL VIV.
基金Supported by National Natural Science Foundation of China(11275085,11305080,11405079 and 11505086)Fundamental Research Funds for Central University of China(lzujbky-2015-69 and lzujbky-2016-36)
文摘The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium depth distribution from the front surface to 500 nm depth was found.The results indicate that an equilibrium deuterium distribution region from the front surface to a depth approximately equal to the mean range of implanted deuterons was formed in Yb during the implantation.The deduced deuterium concentration in the equilibrium deuterium distribution region was D/Yb = 22%.
