A direct observation on overload retardation phenomenon offatigue crack propagation in 60Si_2Mn spring-steel was accomplished ona self-made SEM fatigue loading stage.

By con structing a game model of belated sti mulation,the article reveals the re asons that the belated effects of stimulation come into being.

These results indicate that X-rays lead to genomic instability in HL-7702 cells,which is an important manifestation of radiation-induced delayed effect,and a second radiation stimulus makes the delayed effect in the progeny of the previously irradiated cells be expressed obviously.

Research results indicate a positive teaching effect of the two instruction strategies while the explicit method enjoys a better immediate teaching effect as well as a four-week long delayed effect with a significantly lower percentage of decline.

There are two kinds of hypotheses regarding to delayed-JOL effect, which are memory hypothesis and metamemory hypothesis.