Crystals having this property are said to be doubly refracting , or birefringent.具有这种性质的晶体叫做双折射晶体.Such substances are optically anisotropic and birefringent.这种材料是光学各向异性的,因而是双折射晶体.The stressmeter consists of a short solid...
The Year of Six Million: Math of Population — was Malthus Right?写在世界人口六十亿日: 人口的数学计算——马尔萨斯是否正确?Will Malthus Continue to Be Wrong?马尔萨斯会一直错下去 吗 ?Malthus believed that population increase would outpace increases in the means...
The infantry would use hit and run tactics to slow attacking forces.步兵团可能会使用打了就跑的战术来阻滞进攻部队。The infantry divisions mopped up remaining centres of resistance.陆军各师肃清了残余的抵抗据点。The Belgians fell back as the infantry came under...
In remote regions, the air is pure and the crops are free of poisonous insecticides.在偏远地区，空气很纯净，庄稼也不施用有毒的杀虫剂。Objective To find methods for testing quickly if there were organophosphate and carbamate in insecticides.目的快速检...