The content of this monograph stems from the writer's early involvement with the design of a series of television camera tubes: the orthicon, the image orthicon and the vidicon. These tubes and their variations, have, at different times been the "eyes" of the television system almost from its inception in 1939. It was natural, during the course of this work, to have a parallel interest in the human visual system as well as in the silver halide photographic process. The problem facing the television system was the same as that facing the human visual and the photographic systems, namely, to abstract the maximum amount of information out of a limited quantity oflight. The human eye and photographic film both repre sented advanced states of development and both surpassed, in their performance, the early efforts on television camera tubes. It was particularly true and "plain to see" that each improvement and refinement of the television camera only served to accentuate the remarkable design of the human eye. A succession of radical advances in camera-tube sensitivity found the eye still operating at levels of illumination too low for the television camera tube. It is only recently that the television camera tube has finally matched and even somewhat exceeded the performance of the human eye at low light levels. It was also clear throughout the work on television camera tubes that the final goal of any visual system-biological, chemical, or electronic-was the ability to detect or count individual photons."

This book represents an important contribution by the School of Social Work at the University of Toronto. It is a record of a carefully designed plan to include a worthwhile research experience in the educational programme of every student engaged in graduate education for the profession. In the introductory essay Dr. Albert Rose explains the methods by which this educational objective has been attempted and traces the evolution of the research requirements as a valid learning experience. The abstracts of 398 student projects provide a varied and interesting illustrative record of the students' work. These are not definitive studies but they are fertile in suggestive ideas; and the reported findings, though limited, are studded with clues for further and more intensive study in a wide range of welfare services and in different forms of social work. The result should be a valuable source of ideas for intending researches in this field both of what is known, and perhaps equally important, of how much is not known. The abstracts have been prepared by Margaret Avison, who has also provided an evocative introductory review.

This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1972.

This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1972.

This monograph is a radical departure from the conventional quantum mechanical approach to electron-phonon interactions. It translates the customary quantum mechanical analysis of the electron-phonon interactions carried out in Fourier space into a predominantly classical analysis carried out in real space. Various electron-phonon interactions such as the polar and nonpolar optical phonons, acoustic phonons that interact via deformation potential and via the piezoelectric effect and phonons in metals, are treated in this monograph by a single, relatively simple "classical" model. This model is shown to apply to electron interactions with the deep lying X-ray levels of atoms, with plasmons and with Cerenkov radiation. The unifying concept that applies to all of these phenomena is a new definition of a coupling constant. The essentially classical interaction of an electron with its surrounding is clearly brought out to be the cause of spontaneous emission of phonons. The same concept also applies to the case of spontaneous emission of photons. While the bulk of this monograph deals with quanta of phonons and quanta of photons, a discussion of the acousto electric effect which is a purely classical phenomenon is presented. The newly defined coupling constant turns out to be valid too for this discussion. This universality of the coupling constant goes far beyond. It is equally applicable to amorphous materials. This significant application gives an analytic formulation of mobility in amorphous materials.