| 释义 |
underˈfocus
[under-1 10.]
The situation in which the beam of an electron microscope is focused to a point somewhat short of the specimen. So underˈfocused ppl. a., -ˈfocusing vbl. n.
1953C. E. Hall Introd. Electron Microsc. x. 268 The pattern appearing at the screen is an underfocused image. 1971Jrnl. Physics A IV. 806 These large phase shifts can be exactly cancelled by underfocus of the objective lens. Ibid., This underfocusing will produce a large chromatic aberration. 1979Nature 17 May 227/1 The contrast of the images taken from very thin parts of crystal at about 700 Å underfocus is known to reflect approximately the projection of the structure; the dark dots show the sites of Re ions. |