收集了近相接双星BF Vir 的光极小时刻,并对其轨道周期进行分析.结果表明该星的轨道周期在长期减小的同时也含有30 年的周期性变化.对引起轨道周期变化的各种物理机制的分析研究表明:一个质量为0 .281 M⊙、绕公共质心的轨道半径为10 .2...收集了近相接双星BF Vir 的光极小时刻,并对其轨道周期进行分析.结果表明该星的轨道周期在长期减小的同时也含有30 年的周期性变化.对引起轨道周期变化的各种物理机制的分析研究表明:一个质量为0 .281 M⊙、绕公共质心的轨道半径为10 .2 AU 的第3天体的存在能对轨道周期的周期性变化成份作出解释,如果轨道周期的周期性变化成份是由于次子星的周期性磁活动引起,那么系统总光度就应该有振幅0 .097 L⊙的周期性变化,且其变化周期与轨道周期变化的周期相同;轨道周期的长期减小成份可能是由于该系统质量和角动量损失引起.BF Vir 是一个短周期的近相接双星系统,通过长期的质量和角动量损失它将可能会演化成一个A 次型的相接双星.展开更多
An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designe...An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.展开更多
Using the direct method for a coupled KdV system, six types of the similarity reductions are obtained. The group explanation of the results is also given. It is pointed out that, in order to find all the results by no...Using the direct method for a coupled KdV system, six types of the similarity reductions are obtained. The group explanation of the results is also given. It is pointed out that, in order to find all the results by nonclassical Lie approach, two additional condition equations should be satisfied at the same time together with two original equations.展开更多
文摘收集了近相接双星BF Vir 的光极小时刻,并对其轨道周期进行分析.结果表明该星的轨道周期在长期减小的同时也含有30 年的周期性变化.对引起轨道周期变化的各种物理机制的分析研究表明:一个质量为0 .281 M⊙、绕公共质心的轨道半径为10 .2 AU 的第3天体的存在能对轨道周期的周期性变化成份作出解释,如果轨道周期的周期性变化成份是由于次子星的周期性磁活动引起,那么系统总光度就应该有振幅0 .097 L⊙的周期性变化,且其变化周期与轨道周期变化的周期相同;轨道周期的长期减小成份可能是由于该系统质量和角动量损失引起.BF Vir 是一个短周期的近相接双星系统,通过长期的质量和角动量损失它将可能会演化成一个A 次型的相接双星.
文摘An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.
基金The project supported by National Natural Science Foundation of China under Grant No. 10071033, the Natural Science Foundation of Jiangsu Province under Grant No. BK2002003, the Project of Technology Innovation Plan for Postgraduate of Jiangsu Province in Year 2006 under Grant No. 72, and the Natural Science Directed Foundation of the Jiangsu Higher Education Institutions under Grant No. 06KJDll0001
文摘Using the direct method for a coupled KdV system, six types of the similarity reductions are obtained. The group explanation of the results is also given. It is pointed out that, in order to find all the results by nonclassical Lie approach, two additional condition equations should be satisfied at the same time together with two original equations.
