早在古时,蝗灾就经常肆虐我国北方地区,给当时的劳动生产带来了很大损失.近几年来非洲几次大蝗灾也都使当地人民损失惨重.但是蝗虫是如何迁徙、活动的,人类却对此几乎一无所
A series of directional shear tests on remolded frozen soil was carried out at -10 °C by using a hollow cylinder apparatus to study failure criterion under a directional shear-stress path. Directional
Vegetation plays a significant role in global terrestrial ecosystems and in combating desertification. We analyzed vegetation change in Inner Mongolia of northern China using the Normalized Difference