Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available online.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

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In the study, the effect of current density and rotation speed of grinding disk on characters of Ni-Diamond composite coating are investigated. Experimental results show that current density and film thickness are almost linearly depend. When the current density is increased, the film thickness is increased, too. And it can cover diamond particles much more efficiently. The rotation speed of grinding disk is 20 rpm, the average deposition rate is approx. 2£gm/min in 5 ASD. When reduce the current density to 2.5ASD, the average deposition rate reduce to approx. 1.08£gm/min. The current density is 5 ASD, the covered area of diamond particle in Ni-Diamond composite coating is 60% when the rotation speed of grinding disk is 0rpm. Increasing the rotation speed up to 100 rpm, the covered area of diamond particle in Ni-Diamond composite coating is down to 24% because diamond particle can`t stay in the same position in a long period. Secondary, we use composite electroplating on grinder in process to grind CVD diamond films, the effect of current density and loads on grinding characters of CVD diamond films by using the composite electroplating on grinder in process are investigated. The load is 4.2 kg, the surface roughness Ra is about 0.2 £gm when composite coating grind CVD diamond with no electroplating. But the current density is up to 2.5 ASD, Ra can down to 0.12£gm. The load is increasing to 6.3 kg, the Ra of CVD diamond films is about 0.16£gm.

Take the Quadrangular-Pyramid-Shaped Fiber Endface(QPSFE) and the Conical-Wedge-Shaped Fiber Endface(CWSFE) for example, the present procedure of grinding asymmetric optical fiber endface demands three to four steps. These steps take time and are lack of repeatability and high yield. Aim at the shortcomings, this study develops a set of mechanism to attach to the original optical fiber grinding machine. The mechanism makes the normal pressure between the endface and the grinding plate change periodically to modify the removing rate of the material, thus enables the clipped flat endface of the optical fiber be ground into an elliptic-cone-shaped in a single grinding step, and then becomes a lens after its tip being fused by the arc. This mechanism reduces the fabricating time and cost, and consequently improve the economic benefits as well by simplifying the complicated manufacturing processes that represented before. Besides, for its single-step grinding characteristic, the offset between the center of the fiber and the elliptic-cone can thus be slashed to promote the yield. This study reviews the anterior references, including the papers and the patents, to begin, and then proposes the current means to compare with. Its contents involve the development of the forming principle, which proposes how the variation of the normal pressure takes influence on the removing rate of the material, and the required mechanism for the design procedure. The mechanism, the research result, and those needed to be ameliorated will be demonstrated in the conclusion and discussion part, so as to offer the investigating direction in the future.

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Using the envelope theory, the mathematical model of the end face profile and the working tool path of a special optical fiber polishing machine is deve- loped in this study. During the polishing process, the polisher is controlled by three parameters including the fiber rotational angle, the height H and the angle between the fiber and polisher. The contact points between the optical fiber and the polishing plate will determine the profile of the fiber end face. The 3-D end face with double-variable curvatures can be fabricated by properly controlling these three parameters. Since the grinding (polishing) material removal rate is related to machining time and normal contact force, the grinding (polishing) tool path and parameters are needed some modification in order to get the precise end profiles. Example of fiber end faces of 2-D elliptical face and 3-D ellipsoid are given to check the developed mathematical model in this study by computer solid modeling.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1940. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed March 9, 2010) Includes bibliographical references (p. 60-62) and index (p. 63-64).

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