The paper recommends to increase the retirement ages gradually and to enlarge coverage by old-age social insurance syste.

With the economic development and our social progress,our party and country have been putting emphasis on extending the coverage of social security as well as gradually realizing social justice.

It is important to extend the coverage of the basic social security insurance in the development of socialist market economy and the improvement of people s life quality.

Considering the conventional algorithms for calculating the coverage area of radar net, such as grid-ding based on digital map and edge scanning method, have their inherent limitations, this article presents a new algorithm with point-to-point decision, which is applicable to calculating the coverage area of radardetection in arbitrary form net.

Effects of soil surface mulching on cucumber production and water use efficiency in solar greenhouse;

Soil surface mulching was one of important method to improve the agricultural microclimate.

5℃ in late stage;Soil surface mulching decreased water consumption which was respectively reduced 22.

Effects of ground coverings on radiant energy distribution in the canopy of Eucommia ulmoides Oliv.coppice forest;

In order to provide a basis for researches on effect of ground cover on nonwood forest trees,research progress on effect of it on crops and some .