And the wet curing time had significant effects on the early age shrinkage of mortar.
结果表明:萘系高效减水剂对胶砂试样早期收缩有一定影响,但28d龄期时的收缩值增大了20%—40%;水养护时间对胶砂的收缩变形有明显的影响;掺加有粉煤灰和高效减水剂的低水胶比胶砂,在养护充分的条件下,水胶比小,胶砂的收缩值相对较大。
Nowadays the amount of marine aquaculture wastewater has surpassed the amount of sewage.
当前海水养殖废水的排放量已超过陆源污水,是导致海洋环境不断恶化的重要原因之一。
Marine aquaculture,specially intensive penaeid shrimp pond aquaculture was the new tendency of aquaculture industry recently.
海水养殖,特别是高位虾池养殖是近年来养殖业发展的新趋势,在其带来巨大经济效益的同时,也对周边生态环境带来巨大的威胁和破坏。