| 摘要 |
A machine having a fixed part including a portion with a smooth surface is provided. The machine also includes a rotating part configured to rotate relative to the fixed part, the rotating part directly facing the portion of the fixed part, and plural ridges formed on the portion of the fixed part directly facing the rotating part, the plural ridges comprising an abradable material, wherein the abradable material is configured to be inoperable at temperatures above about 1000° C. |
