In this paper, give an equivalent definition of semi-module.
从半环同态的角度出发，给出了半模的一个等价定义。
2
Some equivalent representations of complex positive semi definite matrices are given by using equivalent conditions of positive semi definite of real symmetric matrix.
利用实对称矩阵的半正定之等价条件给出了复正半定矩阵的几个等价条件。
3
Medical thermoplastic polyether urethanes(TPU) based on MDI/PTMG/BDO system were prepared by one -shot, prepolymer and semi-prepolymer processes with equivalent stoichiometries respectively.