As drilling operations move into remote locations and extreme water depths, recoil analysis requires more careful considerations and the incidence of emergency disconnect is increased inevitably. To accurately capture...As drilling operations move into remote locations and extreme water depths, recoil analysis requires more careful considerations and the incidence of emergency disconnect is increased inevitably. To accurately capture the recoil dynamics of a deep-water riser in an emergency disconnect scenario, researchers typically focus on modelling the influential subsystems (e.g., the tensioner, the mud discharge and seawater refilling process) which can be solved in the preprocessing, and then the determined parameters are transmitted into an existing global riser analysis software. Distinctively, the current study devotes efforts into the coupling effects resulting from that the suspended riser reacts the platform heave motion via the tensioner system in the course of recoil and the discharging fluid column follows the oscillation of the riser in the mud discharge process. Four simulation models are established based on lumped mass method employing different formulas for the top boundary condition of the riser and the discharging flow acceleration. It demonstrates that the coupling effects discussed above can significantly affect the recoil behavior during the transition phase from initial disconnect to the final hang-off state. It is recommended to develop a fully- coupled integrated model for recoil analysis and anti-recoil control system design before extreme deep-water applications.展开更多
Objective To compare the preliminary clinical outcome between fixed platform and rotating high-flexion prosthesis following total knee replacement(TKR).Methods Form January 2007 to December 2009,68 patients with osteo...Objective To compare the preliminary clinical outcome between fixed platform and rotating high-flexion prosthesis following total knee replacement(TKR).Methods Form January 2007 to December 2009,68 patients with osteoarthritis of展开更多
社交商务作为数字经济的重要组成,拥有巨大的市场潜力,但也面临着平台发展模式同质化等问题,导致形成固化用户的自我认识和网络信息行为的信息茧房。由于社交媒体的多样性、群体关系复杂性,茧房效应与社交商务结合的研究有待进一步挖掘...社交商务作为数字经济的重要组成,拥有巨大的市场潜力,但也面临着平台发展模式同质化等问题,导致形成固化用户的自我认识和网络信息行为的信息茧房。由于社交媒体的多样性、群体关系复杂性,茧房效应与社交商务结合的研究有待进一步挖掘。通过中国知网和Web of Science核心集,截至2023年3月31日,检索并筛选获取606篇相关文献,运用社会网络分析方法进行分析。其中300篇中文文献重点探讨个性化推荐算法对信息茧房形成的影响,306篇英文文献更多关注信息茧房与平台和用户行为之间的关系。基于信息茧房相关概念的研究明确其内涵和特征,根据平台、算法和用户3个维度的作用机制分析构建信息同质化视角下信息茧房形成机制框架,即社交平台内外部信息趋同导致了用户选择同质化、平台内容同质化以及用户群体同质化问题,并以正反馈的形式不断加强,最终形成信息茧房。由此,基于同质化视角,分别从政府、平台和用户3个主体层面提出社交商务平台应对信息茧房的策略。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51879161)
文摘As drilling operations move into remote locations and extreme water depths, recoil analysis requires more careful considerations and the incidence of emergency disconnect is increased inevitably. To accurately capture the recoil dynamics of a deep-water riser in an emergency disconnect scenario, researchers typically focus on modelling the influential subsystems (e.g., the tensioner, the mud discharge and seawater refilling process) which can be solved in the preprocessing, and then the determined parameters are transmitted into an existing global riser analysis software. Distinctively, the current study devotes efforts into the coupling effects resulting from that the suspended riser reacts the platform heave motion via the tensioner system in the course of recoil and the discharging fluid column follows the oscillation of the riser in the mud discharge process. Four simulation models are established based on lumped mass method employing different formulas for the top boundary condition of the riser and the discharging flow acceleration. It demonstrates that the coupling effects discussed above can significantly affect the recoil behavior during the transition phase from initial disconnect to the final hang-off state. It is recommended to develop a fully- coupled integrated model for recoil analysis and anti-recoil control system design before extreme deep-water applications.
文摘Objective To compare the preliminary clinical outcome between fixed platform and rotating high-flexion prosthesis following total knee replacement(TKR).Methods Form January 2007 to December 2009,68 patients with osteoarthritis of
文摘社交商务作为数字经济的重要组成,拥有巨大的市场潜力,但也面临着平台发展模式同质化等问题,导致形成固化用户的自我认识和网络信息行为的信息茧房。由于社交媒体的多样性、群体关系复杂性,茧房效应与社交商务结合的研究有待进一步挖掘。通过中国知网和Web of Science核心集,截至2023年3月31日,检索并筛选获取606篇相关文献,运用社会网络分析方法进行分析。其中300篇中文文献重点探讨个性化推荐算法对信息茧房形成的影响,306篇英文文献更多关注信息茧房与平台和用户行为之间的关系。基于信息茧房相关概念的研究明确其内涵和特征,根据平台、算法和用户3个维度的作用机制分析构建信息同质化视角下信息茧房形成机制框架,即社交平台内外部信息趋同导致了用户选择同质化、平台内容同质化以及用户群体同质化问题,并以正反馈的形式不断加强,最终形成信息茧房。由此,基于同质化视角,分别从政府、平台和用户3个主体层面提出社交商务平台应对信息茧房的策略。
