This paper presents an elasto-viscoplastic consistent tangent operator (CTO) based boundary element formulation, and application for calculation of path-domain independentJ integrals (extension of the classicalJ integ...This paper presents an elasto-viscoplastic consistent tangent operator (CTO) based boundary element formulation, and application for calculation of path-domain independentJ integrals (extension of the classicalJ integrals) in nonlinear crack analysis. When viscoplastic deformation happens, the effective stresses around the crack tip in the nonlinear region is allowed to exceed the loading surface, and the pure plastic theory is not suitable for this situation. The concept of consistency employed in the solution of increment viscoplastic problem, plays a crucial role in preserving the quadratic rate asymptotic convergence of iteractive schemes based on Newton's method. Therefore, this paper investigates the viscoplastic crack problem, and presents an implicit viscoplastic algorithm using the CTO concept in a boundary element framework for path-domain independentJ integrals. Applications are presented with two numerical examples for viscoplastic crack problems andJ integrals.展开更多
细胞焦亡被定义为程序性死亡,其特征是细胞肿胀直至细胞膜破裂、细胞内容物释放并激活强烈的炎症反应。糖尿病性骨质疏松症(diabetic osteoporosis,DOP)是糖尿病相关并发症的一种,表现为骨密度降低、骨量减少和骨结构异常,显著增加了骨...细胞焦亡被定义为程序性死亡,其特征是细胞肿胀直至细胞膜破裂、细胞内容物释放并激活强烈的炎症反应。糖尿病性骨质疏松症(diabetic osteoporosis,DOP)是糖尿病相关并发症的一种,表现为骨密度降低、骨量减少和骨结构异常,显著增加了骨折风险。越来越多的研究揭示,在DOP中,成骨细胞由于各种因素的影响,释放了如NOD样受体热蛋白结构域蛋白3(NOD like receptor protein structure domain protein 3,NLRP3)和白细胞介素(IL-1β、IL-18)等媒介物,这些媒介物活化既可以导致细胞焦亡,又在破骨细胞过度分化及骨质疏松症发生中扮演着关键角色。本综述旨在总结细胞焦亡在DOP中的研究进展,并探讨其作为一种潜在的治疗靶点的可能性。展开更多
基金The project supported by National Natural Science Foundation of China(9713008)Zhejiang Natural Science Foundation Special Funds No. RC.9601
文摘This paper presents an elasto-viscoplastic consistent tangent operator (CTO) based boundary element formulation, and application for calculation of path-domain independentJ integrals (extension of the classicalJ integrals) in nonlinear crack analysis. When viscoplastic deformation happens, the effective stresses around the crack tip in the nonlinear region is allowed to exceed the loading surface, and the pure plastic theory is not suitable for this situation. The concept of consistency employed in the solution of increment viscoplastic problem, plays a crucial role in preserving the quadratic rate asymptotic convergence of iteractive schemes based on Newton's method. Therefore, this paper investigates the viscoplastic crack problem, and presents an implicit viscoplastic algorithm using the CTO concept in a boundary element framework for path-domain independentJ integrals. Applications are presented with two numerical examples for viscoplastic crack problems andJ integrals.
文摘在陆地与水域共存的复杂环境中,水陆两栖无人车(amphibious unmanned ground vehicle,A-UGV)跨域(即在水域与陆地之间的路径转换)三维路径规划是一项具有挑战性的任务。为应对这一挑战,提出一种基于地形信息优化启发函数的改进A^(*)算法,并结合最佳下水上岸点检测进行全局路径规划的方法(improved A^(*)path planning with optimal launch and ashore point detection,IA^(*)OLAPD)。对水陆环境进行地图构建,通过动态体素网格对环境点云数据进行分割和评估,将水域和陆地进行区分,并根据地形信息生成2D占用栅格地图、2.5D数字高程图及通行性地图。在路径规划阶段,将2.5D地图的多层地形信息转化为动态权重因子,优化A^(*)算法的启发函数,以增强复杂地形的适应性。在A-UGV跨越陆地和水域的过程中,算法结合路径长度、路径粗糙度、坡度、高程差和下水上岸点处的地形信息等因素,确定最佳的跨域过渡点,从而最小化整体路径代价和风险系数,实现陆地和水域之间的安全高效跨域过渡。仿真实验结果表明,IA^(*)OLAPD算法在水陆两栖跨域路径规划的安全性、稳定性和路径选择合理性方面具有显著优势。
文摘细胞焦亡被定义为程序性死亡,其特征是细胞肿胀直至细胞膜破裂、细胞内容物释放并激活强烈的炎症反应。糖尿病性骨质疏松症(diabetic osteoporosis,DOP)是糖尿病相关并发症的一种,表现为骨密度降低、骨量减少和骨结构异常,显著增加了骨折风险。越来越多的研究揭示,在DOP中,成骨细胞由于各种因素的影响,释放了如NOD样受体热蛋白结构域蛋白3(NOD like receptor protein structure domain protein 3,NLRP3)和白细胞介素(IL-1β、IL-18)等媒介物,这些媒介物活化既可以导致细胞焦亡,又在破骨细胞过度分化及骨质疏松症发生中扮演着关键角色。本综述旨在总结细胞焦亡在DOP中的研究进展,并探讨其作为一种潜在的治疗靶点的可能性。
