The chance of an Interplanetary Coronal Mass Ejection (ICME) observed by widely-separated spacecraft is rare. However, such an event provides us a good opportunity to study the propagation and evolution of ICMEs in th...The chance of an Interplanetary Coronal Mass Ejection (ICME) observed by widely-separated spacecraft is rare. However, such an event provides us a good opportunity to study the propagation and evolution of ICMEs in the heliosphere. On day 72 of 1975, an ICME was observed by Helios 1 at 0.3 AU, while a similar solar wind structure was observed by IMP 8 at Earth on day 70 of 1975. On the basis of comparison of the plasma signatures and the transit time from Helios 1 to IMP 8, we hypothesize the observed ICMEs by both spacecraft are resulted from the same active region on the solar surface. A one-dimensional MHD model was used to track the ICME from Helios 1 (0.3 AU) to Earth. The observed plasma profiles and timing are close to those predicted by our MHD model and thus, give the supports to the model.展开更多
评介隋允康和彭细荣教授的专著《结构拓扑优化ICM方法新进展——概念深化及理论拓展》,其中ICM(independent continuous and mapping)意思是独立、连续和映射,该方法是结构拓扑优化的主流研究方法之一。该书借助于鉴史(力学史)和驭法(...评介隋允康和彭细荣教授的专著《结构拓扑优化ICM方法新进展——概念深化及理论拓展》,其中ICM(independent continuous and mapping)意思是独立、连续和映射,该方法是结构拓扑优化的主流研究方法之一。该书借助于鉴史(力学史)和驭法(方法论),总结了自2014年以来ICM方法的发展成果:深入阐述了ICM方法的阶跃函数的离散本质及对其光滑逼近的近似连续本质、逼近的快慢特性和多种映射策略;介绍了ICM方法的数学基础、求解算法和本体理论等方面的拓展性研究成果,包括可分离凸规划转换为求解对偶规划显式模型(dual programming-explicit model,DP-EM)解法、互逆规划理论及其优化应用等;探讨了该领域忽视的结构拓扑优化合理化建模问题;发展了包含疲劳寿命性能的局部性能约束的结构拓扑优化解法;归纳了破损-安全设计理论的演化,给出了位移、应力及频率约束的破损-安全拓扑优化问题的建模及求解;移植ICM方法至国际上广泛应用的变密度方法中。该书可供结构优化领域从事科研的师生和技术人员借鉴和参考。展开更多
基金Supported by the National Natural Science Foundation of China(40325010)
文摘The chance of an Interplanetary Coronal Mass Ejection (ICME) observed by widely-separated spacecraft is rare. However, such an event provides us a good opportunity to study the propagation and evolution of ICMEs in the heliosphere. On day 72 of 1975, an ICME was observed by Helios 1 at 0.3 AU, while a similar solar wind structure was observed by IMP 8 at Earth on day 70 of 1975. On the basis of comparison of the plasma signatures and the transit time from Helios 1 to IMP 8, we hypothesize the observed ICMEs by both spacecraft are resulted from the same active region on the solar surface. A one-dimensional MHD model was used to track the ICME from Helios 1 (0.3 AU) to Earth. The observed plasma profiles and timing are close to those predicted by our MHD model and thus, give the supports to the model.
