Certain types of electrostatic fields may be used as lenses to focus electron beams. The theory of these lenses is developed for electric fields that are symmetrical about a central axis. The introduction of two velocity functions exactly reduces the partial differential equations of electron motion to a series of ordinary differential equations. The first equation describes the action of a lens for electron paths near the axis; the remaining equations determine the higher order aberration terms. Sections on the following subjects are included: the general equations of electron‐optics, thin lenses, thick lenses, aberration, the reduction of aberraration, apertured plates, and concentric tubes. A list of symbols and lens equations is also included at the end of the article.
Sparked by a groundbreaking Amsterdam workshop titled "Disorderly Order: Colours in Silent Film," scholarly and archival interest in colour as a crucial aspect of film form, technology and aesthetics has enjoyed a resurgence in the past twenty years. In the spirit of the workshop, this anthology brings together international experts to explore a diverse range of themes that they hope will inspire the next twenty years of research on colour in silent film. Taking an interdisciplinary approach, the book explores archival restoration, colour film technology, colour theory, and experimental film alongside beautifully saturated images of silent cinema.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.