5.21磁悬液污染测定时,在白光和紫外光(用于荧光磁悬液)下观察,梨形沉淀管沉积物中如明显分成两层,当上层污染物体积超过全部沉积物体积的30%时为污染。( )

21磁悬液污染测定时，在白光和紫UV外光（用于荧光磁悬液）下观察，梨形沉淀管沉积物中如明显分成两层，当上层污<|endoftext|> The gravitational pull of the moon on the Earth creates a bulge of water on the side of the Earth facing the moon. This bulge is what we perceive as high tide. On the side of the Earth opposite the moon, there is also a bulge of water due to the centrifugal force caused by the Earth and moon's rotation around a common center of mass. This bulge is what we perceive as low tide. As the Earth rotates, different parts of the Earth experience these bulges and thus experience high and low tides.