Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Amplifier. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

Gyromagnetic resonance fourier transform zeugmatography

Abstract: An improved technique is disclosed for forming two- or three-dimensional images of a macroscopic sample by means of gyromagnetic resonance. A train of free induction decay transient resonance signals are induced and detected from a sample in a region to be imaged. A sequence of pulsed magnetic field gradients are applied during the series of free induction decay signals to derive sets of gyromagnetic resonance data as a function of the changing magnetic field gradients. Two- or three-dimensional images are reconstructed from the sets of resonance data by two- or three-dimensional Fourier transformation.

Explorations in Student-Controlled Instruction:

Abstract: Several studies are briefly described demonstrating that adult learners enter a learning situation with varying amounts of relevant knowledge and that, given control of their curriculum, they tend to be able to direct their learning activities in a way that will lead them to achieve specified objectives. A discussion of those results leads to the suggestion that large gains in program improvement might be achieved by: (a) development of effective methods for detecting the relevant background level of the incoming student, and for adjusting the curriculum accordingly, and (b) development of techniques the learner himself can use to efficiently generate a curriculum which will lead him as economically as possible to the objectives. Research emphasis should thus be focused on subject matter selection as well as on subject matter presentation.

Through-substrate source contact for microwave fet

Abstract: A microwave field effect transistor (FET) comprises source, gate, and drain electrodes deposited on an epitaxial layer grown on a semi-insulating substrate. The FET has lowered thermal resistance, lowered source lead inductance, and lowered gate series resistance, together with concomitant performance improvements, through the use of a novel source electrode connection which comprises a deposited or plated through metallic contact extending from the bottom of the wafer, through a hole in the substrate and epitaxial layer, to the underside of the source or other electrode which is deposited on the top side of the epitaxial layer. The chip, comprising the substrate, epitaxial layer, and top electrodes, is mounted on a heat sink. The chip's underside, including the bottom surface of the plated through source contact, is conductively bonded to the top surface of the heat sink.

Radiotherapy apparatus equipped with low dose localizing and portal imaging X-ray source

Abstract: Apparatus equipped for both megavoltage radiotherapy and a diagnostic X-ray source for portal imaging Both the high energy therapeutic and low energy diagnostic source of radiation are physically located at the same point in apparatus space, and utilize a single moveable target converter that is physically positioned according to the desired use, either therapy or diagnostics