Religion-based websites are fast becoming a major pipeline for disseminating religious information to broad populations of individuals in the United States.Both mainstream religions and fringe religions are easily acc...Religion-based websites are fast becoming a major pipeline for disseminating religious information to broad populations of individuals in the United States.Both mainstream religions and fringe religions are easily accessible to a large population of internet users. The purpose of this review is to develop and examine a general framework that uses simple mathematical and statistical models to interpret and measure temporal ‘snap shots’ in the popularity of religious websites. We extend this framework to include an evolutionary model that has the potential to predict long-term shifts or changes in the popularity of religious websites over time. Ultimately, the goal of this review is to introduce a new modeling framework for research into how the internet is changing the accessibility and views of populations of individuals who follow various religions on the internet and how this may in-turn affect the distribution of religion in the ‘real world’.展开更多
Gaussian-type soliton solutions of the nonlinear Schr?dinger(NLS)equation with fourth order dispersion,and power law nonlinearity in the novel parity-time(TP)-symmetric quartic Gaussian potential are derived analytica...Gaussian-type soliton solutions of the nonlinear Schr?dinger(NLS)equation with fourth order dispersion,and power law nonlinearity in the novel parity-time(TP)-symmetric quartic Gaussian potential are derived analytically and numerically.The exact analytical expressions of the solutions are obtained in the first two-dimensional(1D and 2D)power law NLS equations.By means of the linear stability analysis,the effect of power law nonlinearity on the stability of Gauss type solitons in different nonlinear media is carried out.Numerical investigations do confirm the stability of our soliton solutions in both focusing and defocusing cases,specially around the propagation parameters.展开更多
In drilling a deepwater well,the mud density window is narrow,which needs a precise pressure control to drill the well to its designed depth.Therefore,an accurate characterization of annular flow between the drilling ...In drilling a deepwater well,the mud density window is narrow,which needs a precise pressure control to drill the well to its designed depth.Therefore,an accurate characterization of annular flow between the drilling riser and drilling string is critical in well control and drilling safety.Many other factors influencing the change of drilling pressure that should be but have not been studied sufficiently.We used numerical method to simulate the process of drill string rotation and vibration in the riser to show that the rotation and transverse vibration of drill string can increase the axial velocity in the annulus,which results in the improvement of the flow field in the annulus,and the effect on pressure loss and its fluctuation amplitude.In addition,there are also multiple secondary flow vortices in the riser annulus under certain eccentricity conditions,which is different from the phenomenon in an ordinary wellbore.The findings of this research are critical in safely controlling well drilling operation in the deepwater environment.展开更多
文摘Religion-based websites are fast becoming a major pipeline for disseminating religious information to broad populations of individuals in the United States.Both mainstream religions and fringe religions are easily accessible to a large population of internet users. The purpose of this review is to develop and examine a general framework that uses simple mathematical and statistical models to interpret and measure temporal ‘snap shots’ in the popularity of religious websites. We extend this framework to include an evolutionary model that has the potential to predict long-term shifts or changes in the popularity of religious websites over time. Ultimately, the goal of this review is to introduce a new modeling framework for research into how the internet is changing the accessibility and views of populations of individuals who follow various religions on the internet and how this may in-turn affect the distribution of religion in the ‘real world’.
文摘Gaussian-type soliton solutions of the nonlinear Schr?dinger(NLS)equation with fourth order dispersion,and power law nonlinearity in the novel parity-time(TP)-symmetric quartic Gaussian potential are derived analytically and numerically.The exact analytical expressions of the solutions are obtained in the first two-dimensional(1D and 2D)power law NLS equations.By means of the linear stability analysis,the effect of power law nonlinearity on the stability of Gauss type solitons in different nonlinear media is carried out.Numerical investigations do confirm the stability of our soliton solutions in both focusing and defocusing cases,specially around the propagation parameters.
基金The research work in this paper is supported by the National Natural Science Foundation of China(Grant No.U1762211)National Key Technologies R&D Program of China(Grant No.2016ZX05022-005),This research is also partially supported by Tubular Goods Research Institute of CNPC and State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Material of China National Petroleum Corporation.
文摘In drilling a deepwater well,the mud density window is narrow,which needs a precise pressure control to drill the well to its designed depth.Therefore,an accurate characterization of annular flow between the drilling riser and drilling string is critical in well control and drilling safety.Many other factors influencing the change of drilling pressure that should be but have not been studied sufficiently.We used numerical method to simulate the process of drill string rotation and vibration in the riser to show that the rotation and transverse vibration of drill string can increase the axial velocity in the annulus,which results in the improvement of the flow field in the annulus,and the effect on pressure loss and its fluctuation amplitude.In addition,there are also multiple secondary flow vortices in the riser annulus under certain eccentricity conditions,which is different from the phenomenon in an ordinary wellbore.The findings of this research are critical in safely controlling well drilling operation in the deepwater environment.
