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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.
151

Effect of capacitor discharge welding on single crystal copper

Thaneepakorn, Wiwat 15 March 1999 (has links)
Materials which can be changed in shape and size when exposed to a magnetic field are called magnetostrictive materials. The magnetostrictive material was developed for use in the many actuator industries. A single crystal of magnetostrictive material is used to maximize its magnetostrictive response. It can be produced by the crystal growth method. However, a single crystal from this method is limited in size and shape. The growth direction of a single crystal, sometimes, is different from its magnetostrictive axis. Capacitor discharge welding (CDW) is a high power density welding process at 10���-10��� Kelvin/second. The fusion zone of CDW is very small and the heat affected zone of CDW is rarely detectable. The amount of material affected by heat in the welding process is very small. The objective of this study is to use capacitor discharge welding (CDW) to join single crystal copper and determine the effect of CDW on the microstructure of the single crystal copper. To minimize the cost of using single crystal copper, low oxygen copper C101 (polycrystalline) is used as a replacement. By maximizing the weld strength, Response Surface Methodology (RSM) is used to find the optimum condition of single crystal copper. The single crystal copper was cut at different orientations and welded together with the one that had same orientation to compare the results. The metallography was used to study voids, fusion zone and dislocations of the single crystal copper after welding. After analyzing the effect of the CDW process on the single crystal, the effect of crystal orientation upon void formation was found statistically inconclusive. Small fusion zone as 0.09154 mm was found. No heat affected zone of single crystal was detected. Also, no microstructural damage was found along the fusion zone. Dislocation density before and after CDW were not different because there was no statistically significant difference between the etch pit density in the fusion zone and that outside the fusion zone. In summary, regardless of voids, CDW may be a useful method for welding single crystal metals. / Graduation date: 1999
152

Synthesis, characterization, and crystal chemistry of new borate optical materials

Cox, James Raymond 23 November 1993 (has links)
Graduation date: 1994
153

Active photonic crystal devices /

Tinker, Mark Thomas. January 2006 (has links)
Thesis (Ph. D.)--University of Texas at Dallas, 2006. / Includes vita. Includes bibliographical references (leaves 138-149).
154

Sample preparation and ultrasonic measurement of phononic crystal /

Sun, Ke. January 2007 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 79-82). Also available in electronic version.
155

Silica colloidal crystals as new materials for biomolecule separations

Le, Thai Van. January 2007 (has links)
Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Mary J. Wirth, Dept. of Chemistry and Biochemistry. Includes bibliographical references.
156

Design, fabrication, and applications of dispersion-engineered photonic crystal devices

Lu, Zhaolin. January 2007 (has links)
Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Dennis W. Prather, Dept. of Electrical and Computer Engineering. Includes bibliographical references.
157

Semiconductor-based nanophotonic and terahertz devices for integrated circuits applications

Lin, Chunchen. January 2006 (has links)
Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Dennis Prather, Dept. of Electrical and Computer Engineering. Includes bibliographical references.
158

Fabrication of two-dimensional and three-dimensional photonic crystal devices for applications in chip-scale optical interconnects

Venkataraman, Sriram. January 2006 (has links)
Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Dennis W. Prather, Dept. of Electrical and Computer Engineering. Includes bibliographical references.
159

An investigation of undoped and impurity added SrTiO3 /

Balachandran, U. January 1980 (has links)
Thesis (Ph. D.)--Oregon Graduate Center, 1980.
160

Structural study of Germanium (11) phthalocyanine

Robertson, William Harold 03 June 2011 (has links)
Germanium(ll)phthalocyanine forms crystals belonging to space group P2/c with a=27.11, sigma=0.012 Å, b=10.39, sigma=0.020 Å, c=21.96, sigma=0.014 Å, beta=107.86, sigma-0.0680. There are eight molecules per unit cell.Patterson maps show that the molecule is planar, that the molecular axis is inclined 500 to the b axis, and that molecules are located parallel to each other along the b axis with an interplanar distance of 3.9 Å.

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