高效液相色谱法测定庆大霉素C组分依据()
A.紫外光照射下能产生荧光
B.药物组分衍生物的紫外吸收
C.麦芽酚反应
D.重氮-偶合反应
E.羟肟酸铁呈色反应
参考答案:B
开普勒望远镜的物镜和目镜的成像原理分别和下列哪一组仪器的成像原理类似( )
A.投影仪、放大镜
B.照相机、放大镜
C.放大镜、照相机
D.照相机、投影仪
Because of Einstein’s Theory of Relativity, scientists never again regarded the world .
A.as before they did
B.as they regarded before
C.as they did before
D.as they had before