"I went over to Africa as a socialist, and after about five or six years of hitting my head against the wall, became a small "c" capitalist."

VOA: standard.2010.08.09

And so the photons hitting the wall actually put pressure on the wall, but the pressure is so low.

所以光子碰撞墙面,事实上在对墙加压，但只是压力很小。

麻省理工公开课 - 固态化学导论课程节选

When I am looking at that wall, its photons are hitting the wall and coming back to me.

当我盯着墙看的时候，光子撞击墙面,又回到我眼中来。

麻省理工公开课 - 固态化学导论课程节选