Typical power outputs of commercially available diode lasers are on the order of 5 milliwatts. This thesis discusses the growth, processing and fabrication of high power (lOO's of milliwatts) diode lasers. Devices were grown by Molecular Beam Epitaxy (MBE) and by Metal Organic Chemical Vapor Deposition (MOCVD). The MOCVD diode lasers demonstrated room temperature laser operation with peak output powers of 450 mW/facet pulsed mode. The MBE diode lasers demonstrated room temperature pulsed laser operation of 110 mW/facet. The dynamics of the quantum well structure were studied. The carrier concentration, threshold current density and coatings were modeled. It was demonstrated through transmission line analogies that, depending on the thickness of the high reflective coating, the result would be a high output power diode laser or a superluminescent device. The MBE device was coated with a high power coating resulting in a peak power of 450 mW. The MOCVD device was used to study the superluminescence resulting from specific coatings. / Graduation date: 1992

Nickel contaminated wastewater from plating industries is a major environmental concern. Current treatment methods are often expensive and can also create additional problems. Biosorption is an alternative treatment method that uses inexpensive biomaterials to sequester metals from aqueous solutions. In this study, acid washed barley straw (AWBS) was used for adsorbing nickel ions (Ni2+) from simulated nickel plating wastewater. The adsorption process was rapid and the equilibrium was reached in about an hour. An increase in the initial nickel concentration increased the equilibrium nickel uptake, and the maximum uptake was found to be 8.45 mg/g of AWBS when the initial nickel concentration was1000 mg/L at pH 5. Nickel adsorption was favorable at room temperature than 5oC and 40oC, better adsorption rate and equilibrium uptake was observed at 23oC. Increasing the pH from 3 to 7 increased the equilibrium nickel uptake and the maximum uptake was observed at pH 7, whilst the initial nickel ion concentration was 100 mg/L. The Freundlich isotherm model exhibited better fit with the equilibrium data than the Langmuir equation. Nickel was desorbed using hydrochloric acid solution at pH 2 and the desorption efficiency was 86%. FT-IR studies indicated the participation of hydroxyl, carboxyl and amide groups from cellulose, hemi-cellulose, protein and lignin of barley straw.

Nickel contaminated wastewater from plating industries is a major environmental concern. Current treatment methods are often expensive and can also create additional problems. Biosorption is an alternative treatment method that uses inexpensive biomaterials to sequester metals from aqueous solutions. In this study, acid washed barley straw (AWBS) was used for adsorbing nickel ions (Ni2+) from simulated nickel plating wastewater. The adsorption process was rapid and the equilibrium was reached in about an hour. An increase in the initial nickel concentration increased the equilibrium nickel uptake, and the maximum uptake was found to be 8.45 mg/g of AWBS when the initial nickel concentration was1000 mg/L at pH 5. Nickel adsorption was favorable at room temperature than 5oC and 40oC, better adsorption rate and equilibrium uptake was observed at 23oC. Increasing the pH from 3 to 7 increased the equilibrium nickel uptake and the maximum uptake was observed at pH 7, whilst the initial nickel ion concentration was 100 mg/L. The Freundlich isotherm model exhibited better fit with the equilibrium data than the Langmuir equation. Nickel was desorbed using hydrochloric acid solution at pH 2 and the desorption efficiency was 86%. FT-IR studies indicated the participation of hydroxyl, carboxyl and amide groups from cellulose, hemi-cellulose, protein and lignin of barley straw.

This study presents thin film transistor (TFT) electrode structures in flat panel displays by imprint and electroless silver plating techniques. Imprint technique is not limited to the physical properties of optical lithography. In the imprinting process, the glass mold designed for imprinting process is fabricated by semiconductor manufacturing technology to imprint photoresist (AZ-650). The material is evaluated for imprint process. In addition, at present, electrode materials used in TFT process are aluminum (Al), chromium (Cr) and so on. In other research, the thin film plating technique adopts sputtering process to manufacture TFT electrode structures. This study uses electroless silver plating process to fabricate TFT electrode structures. The experimental result shows that the silver film can be deposited on the glass wafer by electroless plating, The mechanical properties of the silver films such as hardness, coefficient of elasticity and Young¡¦s module are measured by nanoindentation system,compared with the bulk materials.

Traditionally, there are several kinds of method for restraining wear. Usually, it includes the choice of the best operating conditions, the surface coating, the surface heat treatment, and the choice of the best lubricants. Among these methods, only the choice of the best lubricants has the mendable process of chemical element for worn surface, others do not have the mendable process. Consequently, this project proposes a method of continuous tribo-plating, and takes preliminary experiments by using SUJ2 ball specimen and S45C disk specimen to investigate the effects of rotational speed, anode¡¦s density of current, and specimen¡¦s surface roughness on the coating growing rate and the coefficient of friction. Results show that the coating growing rate increases with increasing rotational speed and anode¡¦s density of current, but it doesn¡¦t be influenced by surface roughness. According to the experimental results, it is found that the frictional coefficient in order is uncoated specimen, coated specimen, and continuous coated specimen. Furthermore, at continuous tribo-plating test, specimen whose surface roughness is rough has lower frictional coefficient. According to the analyses of surface pattern and composition, specimen whose surface roughness is rough remains a lot of piece-like coating film on the surface, and this residual film provides a good effect of lubrication. The result of this project proves that continuous tribo-plating not only reduces frictional loss but also has the mendable process of worn surface.

In conventional abrasive machining , it must using dresser to dress the surface of polishing disc periodically , in order for polishing disc to maintain its ability of machining , and then ensuring the quality of work piece. It will make polishing disk thin , finally it must losing it ability of machining , and then be replaced by a new disc. For this reason , in the study , an idea of a new type ultraprecision polisher is proposed . Using Sn-Al2O3 composite coating to reach the mirror surface grinding of silicon wafer in the tin bath , and grinding with electroplating continuously . It will ensure the ability of machining of polishing disc . In the study , first , analyzing the effect of rotational speed rate of wafer and polishing disc on the grinding trajectories type of machining surface . From the result of analysis , find that , when the rotational speed rate is more irregular or it could not divided , the arrangement of grinding trajectories is more complex . And then , investigating the effect of cathode current density , rotational speed of polishing disc and time of plating on the characteristics of composite coating . In the experiment of composite electroplating , when cathode current density is higher , the size of crystal is smaller , the thickness of coating is thicker , and the quantity of Al2O3 within coating decrease lightly . The increase of the rotational speed of polishing disk could increase the size of crystal , the thickness of coating and the quantity of Al2O3 lightly . The time of plating is longer , the shape of crystal is more obvious , the thickness of coating is thicker and it also increase the quantity of Al2O3 . Finally , investigating the effect of cathode current density and cationic surfactant PEI on the characteristics of coating and wafer . In practical abrasive machining , the removal rate of wafer increases with cathode current density , and the addition of PEI could increase the quantity of Al2O3 indeed . Besides , under the same machining condition , in the tin bath with PEI , the removal rate is higher than the one in the tin bath without PEI .

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Deposition rate; zirconia; TBC; texture; microstructure; EB-PVD. Includes bibliographical references (p. 78-79).

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1940. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed March 10, 2010) Includes bibliographical references (p. 56-57) and index (p. 58-59).