Given an alphabet ∑ and a finite minimal set B of forbidden words,a combinatorial enumeration problem on bacterial complete genomes is transformed to enumerating strings of a given length which do not contain any str...Given an alphabet ∑ and a finite minimal set B of forbidden words,a combinatorial enumeration problem on bacterial complete genomes is transformed to enumerating strings of a given length which do not contain any string in B as their substrings.From the fact that a string in the language is equivalent to a path in the corresponding graph,we have obtained a polynomial time algorithm by modifying the power of the adjacency matrix in the graph.展开更多
ZrO3 and HfO3 molecules were prepared via reactions of metal monoxides with dioxygen in solid argon and were characterized using matrix isolation infrared absorption spectroscopy as well as theoretical calculations. U...ZrO3 and HfO3 molecules were prepared via reactions of metal monoxides with dioxygen in solid argon and were characterized using matrix isolation infrared absorption spectroscopy as well as theoretical calculations. Unlike the titanium monoxide molecule, which reacted spontaneously with dioxygen to form TiO3, the ZrO and HfO molecules reacted with dioxygen to give the ZrO3 and HfO3 molecules only under visible light irradiation. Density functional calculations predicted that both the ZrO3 and HfO3 molecules possess a closed-shell singlet ground state with a non-planar C8 geometry, in which the side-on coordinated O2 falls into the peroxide category.展开更多
基金This research is supported by the National Natural Science Foundation of China (No. 10271103) Natural Science Foundation of Yunnan Province(No. 2003F0015M).
文摘Given an alphabet ∑ and a finite minimal set B of forbidden words,a combinatorial enumeration problem on bacterial complete genomes is transformed to enumerating strings of a given length which do not contain any string in B as their substrings.From the fact that a string in the language is equivalent to a path in the corresponding graph,we have obtained a polynomial time algorithm by modifying the power of the adjacency matrix in the graph.
基金Ⅴ. ACKNOWLEDGMENTS This work was supported by the National Basic Research Program of China （No.2007CB815203） and the National Natural Science Foundation of China （No.20773030）.
文摘ZrO3 and HfO3 molecules were prepared via reactions of metal monoxides with dioxygen in solid argon and were characterized using matrix isolation infrared absorption spectroscopy as well as theoretical calculations. Unlike the titanium monoxide molecule, which reacted spontaneously with dioxygen to form TiO3, the ZrO and HfO molecules reacted with dioxygen to give the ZrO3 and HfO3 molecules only under visible light irradiation. Density functional calculations predicted that both the ZrO3 and HfO3 molecules possess a closed-shell singlet ground state with a non-planar C8 geometry, in which the side-on coordinated O2 falls into the peroxide category.
文摘从系统论的思想出发,以提升系统的驱动力矩为广义力,运用动力学理论和拉格朗日方程法建立提升系统多自由度的弹性体、刚体混合系统的动力学模型;以堵转工况、斗杆垂直动臂并全伸出状态为计算条件,采用矩阵迭代法和编程计算提升系统的振动响应,计算出高速轴和提升钢丝绳的动载荷系数为1.343和1.374;计算并分析了堵转时间及不同土壤刚度因素对提升系统动载荷的影响关系曲线,得出了不同土壤刚度的动载荷系数.同时,为降低动载荷并保证设备安全工作,建议堵转时间不宜超过2.0 s.
