Principles Of Image Formation Research Articles

Field-ion microscopy

Summary Field-ion microscopy is a comparatively new technique for studying the internal structure of solids. It is also unique in that it is able to resolve the individual atoms composing the solid structure. The basic principles of image formation are described at some length, although with the avoidance of complex mathematical detail. Examples are presented of the range of applications of the technique. These include the investigation of lattice defects, and the mechanism of phase transformations and surface reactions. The range of materials able to be studied has recently become greatly increased, and the refinements in technique responsible are discussed. Finally a look is taken at those areas where the future application of field-ion microscopy appears to lie.

High Resolution Electron Microscopy of Crystals

AbstractIt is now possible to resolve the basic periodicity of the arrangement of atoms or molecules in crystal lattices using the electron microscope. Examples are given of lattices resolved directly (including superlattices), and indirectly (by means of moire patterns) and of other periodic phenomena associated with crystal lattices (domains in ordered alloys). The basic principles of image formation in periodic objects are considered in terms of simple diffraction theory and some indications given of limiting factors in this type of investigation.

11. The teaching of geometrical optics by means of the gauss system with special reference to the formation of images

The teaching of optics should be based upon the principles of image formation treated according to the Gauss system, the nature of the approximations which are involved being duly explained. The Cartesian convention as to signs should be applied, with the origin at a suitable fixed point in the system while the light is always considered to come from the left. No convention should be used in which the signs change with the nature of the lens.