It gives the methods and equations of the affection of the cochannel interference on the communication system based on the concepts of cochannel interference degree on the condition that only one interference exists.

A new criterion named interferential degree of background was proposed to estimatethe quality of infrared small target image.

First,this paper presents the jamming equation.

According to the demands of tactic use of ship towed radar active decoy, two jamming equation on the condition of plan jamming and line jamming are deduced, and using the ship and incoming missile′s actual parameters, the transmitting power of ship towed radar active decoy is calculated based on line jamming.

ESJ is common in the modern radar jamming technology,this paper introduces a calculating method of radar s detection area by using jamming equation on the condition of ESJ.

The new interferential distance is longer than the originally short dispersion of atmosphere for three times, which was produced by bad pollution of atmosphere.

The results showed that with the increasing of human-induced disturbance intensity, the amounts of small soil particle (silt and clay) and large aggregate decreased, and the amounts of soil micro-aggregate and natural soil particle increased; soil porosity decreased in the surficial soil,especially, in which the large porosity significantly decreased;.

We want to know the quantitative relation of the disturbance intensity and the forest structure.

The partition of ecological environment according to disturbance degree can direct and regulate the disturbance intensity and pattern of human activities,favoring to rationally develop resources and to protect ecological environment.

We selected nine main index about the human activity,and calculated the connection degree of human activity and soil erosion by the gray system theories,then discussed the disturbance degree of human activity to soil erosion.