The magnet creates a field which changes the polarity of a tiny, tiny portion of the metal particles which coat each platter's surface.

这个磁体创建一个,能改变覆盖在,磁盘表面小金属粒子的磁极。

哈佛公开课 - 计算机科学课程节选

Starting with two silicon wafers, Soitec machines coat the surface of one with silicon dioxide insulator and embed inside it a thin fault line of hydrogen atoms anywhere from 100 to 20, 000 nanometers below the surface, depending on customers' desired wafer thickness.

FORBES: Magazine Article

The forensics expert said the outer surface of April's coat was waterproof and would not shed fibres but the lining and fake fur of the hood could.

BBC: April Jones

While most brass pens are heavily lacquered to preserve their lustre, the Hatch is finished with just a thin coat intended to wear away quickly, leaving the hygienic surface exposed.

WSJ: To Contagions, This Pen Is Deadlier Than the Sword