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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Contact Pressure Distribution Optimization

Hric, George Richard III 27 June 2016 (has links)
A novel design technique that is used to optimize contact pressure distribution was introduced and investigated. The primary objective of this design tool, called the Predicted Displacement Method, was to provide a calculated contact surface shape alteration of a contact body that induces a uniform contact pressure across its entire nominal contact surface when pressed against its destination contact boundary at a specified magnitude. This technique was developed so it could be applied to any contact surface to spread out a once poorly distributed and localized contact pressure distribution. The methodology was detailed in this work and a proof of concept was conducted to test the idea's feasibility. The proof of concept supported the methodology's ability to shape a cantilevered beam so that it pressed against a semi-infinite space uniformly. This methodology was then applied to two relevant contact assemblies and resulted in uniform contact across each contact interface. The results also illustrated the ability to control contact magnitude and demonstrated improved contact distribution at magnitudes beyond the design value. The methodology presented in this work provides engineers with a analytical and numerical tool to improve contact pressure distribution between any contact surfaces. Possible future use of this methodology includes incorporation into engineering software packages for contact surface design. / Master of Science

The Studies of High Voltage Drive for Gallium Phosphide Light Emitting Diode

Ni, Ining-Gia 30 June 2000 (has links)
ABSTRACT It is very common that the driven voltage of the Light emitting diode device is around 1.8eV~2.2eV, however, in its applications the voltage that applied on the circuit is higher than this specification (3 eV as usual). It will be very annoying that the design of the LED circuit should always be in series with an extra resistor in order to protect the LED. In here we propose a method with a schottky contact structure on the device that we can solve this problem. Before we proceed this method, we had better fully understand the characteristics of the material physical properties , schottky contact and ohmic contact ,also include of the process of device. The substrate of the LED diode was chosen with N-GaP(111). The metal for the ohmic contact in this device is composed of Au/Au-Ge alloy. As to the schottky contact , the metal is formed by using Au element. The techniques for characterizing these contact properties include current-voltage (I-V), specific contact resistance (rc), ideal factor and current transport etc. The LED diode is also annealed at 450ºC for 10 minutes for improving the performance. The X-ray diffraction technique is applied to Investigate the interface of the contact area. The results of this experiment are summarized below: (I) The I-V curve of Ohmic contact is linear and contact resistance irc =7

Contact projective structures and contact path geometries /

Fox, Daniel Jeremy Forrest, January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 174-178).

Über eine Berührungstransformation, die den Punkten des einen Feldes Geradenpaare zuordnet

Schilling, Bernhard. January 1919 (has links)
Thesis (doctoral)--Technische Hochschule zu Dresden, 1919.

Untersuchung einer linear-quadratischen Berührungstransformation

Wilson, Harry, January 1913 (has links)
Thesis (doctoral)--Universität Rostock, 1913. / Vita.

Studies of advancing and receding contact angles

Johnson, Barbara Alice. January 1982 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 64-68).

Contact Sensing from Force Measurements

Bicchi, Antonio, Salisbury, J. Kenneth, Brock, David L. 01 October 1990 (has links)
This paper addresses contact sensing, i.e. the problem of resolving the location of a contact, the force at the interface and the moment about the contact normals. Called "intrinsic'' contact sensing for the use of internal force and torque measurements, this method allows for practical devices which provide simple, relevant contact information in practical robotic applications. Such sensors have been used in conjunction with robot hands to identify objects, determine surface friction, detect slip, augment grasp stability, measure object mass, probe surfaces, control collision and a variety of other useful tasks. This paper describes the theoretical basis for their operation and provides a framework for future device design.

Investigation of the relative motion that develops between the surfaces of a pair of inter-rolling bodies, one of which is supported by the other whenever a tangential force is applied to the supported body /

Wight, Hugh Humphrey. January 1961 (has links) (PDF)
Thesis--University of Adelaide, 1961. / Typewritten.

Surface separation and contact resistance considering sinusoidal elastic-plastic multiscale rough surface contact

Wilson, W. Everett, Jackson, Robert L., January 2008 (has links)
Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 77-79).

Développement de briques technologiques pour la réalisation de diodes schottky sur nitrure de gallium / Development of technological bricks for the achievement of gallium nitride based Schottky diodes

Menard, Olivier 25 November 2010 (has links)
Ce travail de thèse porte sur la réalisation d’une diode Schottky de puissance sur GaN épitaxié sur substrat saphir.La majeure partie du travail a été consacrée au développement du contact ohmique. Différentes conditions de fabrication ont été étudiées autour d’un contact basé sur l’empilement titane-aluminium. De bonnes résistances spécifiques de contact ont été obtenues sur du GaN de type n+ dopé in-situ (autour de 1x10-5 Ω.cm-2) ainsi que sur du matériau implanté silicium et sur des couches dopées in-situ mises à jour après gravure sèche. Nous avons également étudié le contact Schottky, au travers d’une structure simple : « Schottky To Schottky ».Les résultats issus de ces études sur les contacts nous ont permis de réaliser des diodes Schottky latérales et pseudo-verticales. Des hauteurs de barrière de plus de 1eV et des facteurs d’idéalité de 1,05 ont pu être mesurés sur les diodes pseudo-verticales avec, pour certaines, une tension de claquage de 600V. / This work deals with Schottky power diodes achievement mostly on GaN on sapphire substrate.A major part of this work has been dedicated to ohmic contact development. Many process parameters have been studied for a TiAl stack. Good results have been obtained on in-situ highly doped n-type GaN (around 1x10-5 Ω.cm-2) and also on silicon ion implanted GaN layer and on dry-etched in-situ doped GaN layers. Then we have studied Schottky contacts through a simple structure: “Schottky To Schottky”.Combining previous results, we have carried out planar and mesa Schottky diodes. Barrier heights above 1eV and ideality factors of 1.05 have been found on mesa structures with, for some of them, a breakdown voltage of 600V.

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