If the elements of R are either unit or zero divisor,then we call R the Unit-Divisor Ring.

This paper passes in review various cycles inside and outside the sphere of economic and enterprise activities so as to bring out the universality of these cycles,then goes on to deduce the five elements logic for one way causal cycles of business and to display a successful application of the five elements logic in small strict cycle in economic and enterprise activities.

Study on the linearization of single-loop feedforward power amplifiers;

In this paper the main results are following theorems: (1)A prime ring is a primitre ring, asimple ring with unit or a division ring, respectively, if and only if there exists its ideal which is aprimitre ring, a sinple ring with unit or a division ring.

The aim of this note is to show the following:If all maximal left ideals of R are conjugate,then so are all maximal left ideals of matrix ring Rn×n,moreover,R is a local ring or R/J is a simple ring,where J is the Jacobson radical of R.

Using the properties of the ideal of the ring theory,we obtain a sufficient condition of a simple ring to be a division ring and its corollary,and with the weaker inverse proposition of Lagrange s theorem in the group theory,we get the conclusion that the group without proper subgroup must be a finite group of prime order.

The optimal medium components(carbon and nitrogen sources)and growth conditions(initial pH,temperature and rotation speed)for siderphore production by mutant J61321(Alteromonas aurantia)were studied by using one-variable-at-a-time method.