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Full-Text Articles in Engineering
Analysis Of Oscillations In Nonlinear Systems Using Multiple Input Describing Functions, Frederic Lee Swern
Analysis Of Oscillations In Nonlinear Systems Using Multiple Input Describing Functions, Frederic Lee Swern
Dissertations
Sufficient conditions for oscillation as well as absence of oscillations are presented for a class of systems containing one lumped linear element and a differentiable nonlinearity. The results are obtained by estimating the error inherent in using a describing function analysis. Contraction type arguments are used to show common topological properties of the describing function solution and the balance of first harmonic terms of the system.
After discussing the describing function method, two theorems are presented regarding existence or nonexistence of oscillations from homotopic considerations. A graphical method for examining systems with power law nonlinearities is given using a parameter …
Investigations Of Gate Turn-Off Structures, Hans Werner Becke
Investigations Of Gate Turn-Off Structures, Hans Werner Becke
Dissertations
Research and Development was done on gate turn-off devices. The aim was i) to improve turn-off capability without compromise of turn-on, on-state, and useful temperature range, ii) to implement "safe" turn-off.
A) The dependence of the electrical device characteristics on cathode width for an optimized vertical structure was determined. Fall times of 100 to 200 nsec and risetimes of <400 nsec were simultaneously obtained for average current densities of 53 A/cm2 @ Tj = 125°C. From spreading resistance analysis the fast tr and tf response is shown to be a consequence of proper Au-distribution in the active device volume.
From transient analysis it is concluded that for safe …
Statistical Averaging In Position Determination By Holography Under Turbulence Conditions, Paul Aloysius Mcgovern
Statistical Averaging In Position Determination By Holography Under Turbulence Conditions, Paul Aloysius Mcgovern
Dissertations
An investigation of several, disparate phenomena is conducted with the aim of developing a novel surveying system capable of overcoming the limitations imposed by turbulence in modern surveying. This method incorporates standard holographic techniques and time domain statistical averaging of survey data.
Some pertinent characteristics of atmospheric turbulence are reviewed, and the restrictions imposed on standard surveying practices by such turbulence are identified. A model for the turbulent medium is proposed on the basis of previous work and several theoretical results are summarized and extended.
On this basis the technical characteristics of the proposed technique are developed and each step …