E-Book Overview
Nine years has passed since the 1992 second edition of the encyclopedia was published. This completely revised third edition, which is a university and professional level compendium of chemistry, molecular biology, mathematics, and engineering, is refreshed with numerous articles about current research in these fields. For example, the new edition has an increased emphasis on information processing and biotechnology, reflecting the rapid growth of these areas. The continuing Editor-in-Chief, Robert Meyers, and the Board prepared a new topical outline of physical science and technology to define complete coverage. Section editors are either Nobel Laureates or editors of key journals in their fields. Additional Board members representing the global scientific community were also recruited.
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P1: FLV 2nd Revised Pages Qu: 00, 00, 00, 00 Encyclopedia of Physical Science and Technology EN002-95 May 19, 2001 20:57 Charged -Particle Optics P. W. Hawkes CNRS, Toulouse, France I. II. III. IV. Introduction Geometric Optics Wave Optics Concluding Remarks GLOSSARY Aberration A perfect lens would produce an image that was a scaled representation of the object; real lenses suffer from defects known as aberrations and measured by aberration coefficients. Cardinal elements The focusing properties of optical components such as lenses are characterized by a set of quantities known as cardinal elements; the most important are the positions of the foci and of the principal planes and the focal lengths. Conjugate Planes are said to be conjugate if a sharp image is formed in one plane of an object situated in the other. Corresponding points in such pairs of planes are also called conjugates. Electron lens A region of space containing a rotationally symmetric electric or magnetic field created by suitabl