高着色力氧化铁黑颜料的制备
Preparation of High Tinting Strength Black Iron Oxide Pigment
1993年5月4&6日（93.5）在我国西北地区发生了一次极具破坏力的黑风暴。
A black storm with severe destructibility occurred in the Northwest Region of China during 4-6 May 1993 ( 93.5 ) .
力黑