Firstly,condition(R) of rectangular tensors are given upon the definition of strictly nonnegative tensors.Then,some properties of rectangular tensors are discussed when they satisfy the condition.

In order to study the rectangular tensors,this paper proposes definitions of condition (P) and condition (P0) of rectangular tensors.The definitions are generalized from the concepts of P and P0 tensors.It is proved that the H-singular values and Z-singular values of a rectangular tensor are positive(or nonnegative) if the rectangular tensor satisfies condition P (or condition (P0)),then,the rectangular tensor is definite (or semi-definite).Next,the paper shows that the rectangular tensor which satisfies condition (P) does not exist if it is under certain conditions.A necessary and sufficient condition is proposed.Finally,properties of P and P0 tensors are generalized to rectangular tensors.

A method for improving the dimensional stability of viscose plain knitted fabrics is reported in this paper. The research strategy and methodology are introduced, and were verified by experiments.