~(171)Ta高自旋态能级寿命测量

在中国原子能科学研究院的HI 13串列加速器上通过157Gd(19F,5n)171Ta重离子熔合蒸发反应布居了171Ta的高自旋态,以多普勒移动衰减法的峰形分析法分析了171Tah9/2质子1/2[541]转动带的6条能级的寿命,得到了这6条能级的平均寿命值.

Laboratory study on cracks in saturated sands

It has been reported([1]) that when a loosely packed column of saturated sand in a vertical cylindrical container is shock loaded axially by dropping to the floor, large horizontal cracks initiate, grow and eventually fade away in the sand as it settles under gravity. This paper shows that a similar phenomenon can also be observed when shock loading is replaced by forcing water to percolate upward through the sand column. It is believed that our result sheds further light on the physics of formation of these cracks.

力学在现代自然科学和工程中的作用

力学作为“自然哲学的数学原理”,乃是支撑物理科学和工程技术的一个重要支柱。它以产生宏观运动的相互作用为对象,以特有的手法衡量不同因素的相对重要性,从复杂的现象中,定量提炼出主要控制机理,为认识自然提供模型和工具,为工程提供设计基础和先导。