The relations of the three two parameter stopping points are discussed,several commutative conditions of the two parameter stopping point σ field are offered,and two equivalent conditions of the F 4 condition are obtained.
讨论了三种两指标停点的关系，给出了两指标停点σ－域可换的几个条件，得到了Ｆ４条件的两个等价条件。
The fixture consisted of the changeable spares and basic body was introduced.
介绍了一种由可换部件和基体组成的夹具,通过更换可换部件,来达到加工一系列尺寸不同的零件,说明了成组夹具的重要性,为类似批量生产提供了可以节约资金和节省库房空间的方法。
A new feeding screw is designed with fixed-poie and changeable die for trying to improve the performance of present screw briquetters.
针对螺旋进给式制棒机目前存在的主要问题,设计采用由固定杆和可换压头组成的分体式推进器;同时,将机器上箱盖改为快速开合式,解决了推进器可换压头的快速更换。
This paper discussed group algebras of finite generated abelian groups, and determined their derivation algebras.
讨论了任意一个有限生成可换群的群代数 ,并确定其导子代数。
This paper deals with some properties of total sub-semigroups of Abelian groups.
研究可换群的完整子半群的性质，并进一步讨论其扩张问题，得出若干结论。