No description available.

No description available.

Novel net shaping technique Laser Engineered Net shaping™ (LENS) laser based manufacturing solution (Sandia Corp., Albuquerque, NM); Laser can be used to deposit orthopedic implant alloys. Ti-35Nb-7Zr-5Ta (TNZT) alloy system was deposited using LENS. The corrosion resistance being an important prerequisite was tested electrochemically and was found that the LENS deposited TNZT was better than conventionally used Ti-6Al-4V in 0.1N HCl and a simulated body solution. A detailed analysis of the corrosion product exhibited the presence of complex oxides which are responsible for the excellent corrosion resistance. In addition, the in vitro tests done on LENS deposited TNZT showed that they have excellent biocompatibility. In order to improve the wear resistance of the TNZT system boride reinforcements were carried out in the matrix using LENS processing. The tribological response of the metal matrix composites was studied under different conditions and compared with Ti-6Al-4V. Usage of Si3N4 balls as a counterpart in the wear studies showed that there is boride pullout resulting in third body abrasive wear with higher coefficient of friction (COF). Using 440C stainless steel balls drastically improved the COF of as deposited TNZT+2B and seemed to eliminate the effect of “three body abrasive wear,” and also exhibited superior wear resistance than Ti-6Al-4V.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Anna On-Nar Yau. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 155-160. / by Kent A. Stevens. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographical references. / by Hyo-Chol Sin. / Ph.D.

Kam Yuen Kwan = 利用散射及反衝粒子飛行時間譜儀及其他表面分析儀器就LiTaO3對質子及鋰離子交換後改變之研究 / 甘婉君. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Kam Yuen Kwan = Li yong san she ji fan chong li zi fei xing shi jian pu yi ji qi ta biao mian fen xi yi qi jiu LiTaO3 dui zhi zi ji li li zi jiao huan hou gai bian zhi yan jiu / Gan Wanjun. / Acknowledgements --- p.i / Abstract --- p.iii / Table of contents --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Definition of Ferroelectrics --- p.1 / Chapter 1.2 --- Common Properties of Ferroelectrics --- p.2 / Chapter 1.3 --- Polarization --- p.2 / Chapter 1.4 --- Lithium Tantalate (LiTa03) --- p.7 / Chapter 1.4.1 --- Crystal Structure --- p.8 / Chapter 1.4.2 --- Pyroelectric Effect --- p.9 / Chapter 1.4.3 --- Determination of Polarity --- p.10 / Chapter 1.4.4 --- Proton Exchange --- p.11 / Chapter 1.4.5 --- Reverse Exchange --- p.12 / Chapter 1.4.6 --- Applications --- p.13 / Chapter 1.5 --- Emerging Attentions in Surface Properties of Smart Materials --- p.14 / Chapter 1.6 --- Difficulties in Surface Studies of Ferroelectric and Related Smart Materials --- p.15 / Chapter 1.7 --- Recent Developments of TOF-SARS in Our Research Group and Its Applicability on LiTa〇3 --- p.16 / Chapter 1.8 --- Objectives of the Present Thesis Work --- p.17 / Chapter 1.9 --- Organization of the Thesis --- p.17 / Chapter 1.10 --- Reference --- p.18 / Chapter Chapter 2 --- Ion Exchange Processes and Sample Prepartion --- p.20 / Chapter 2.1 --- Fundamental of Ion Exchange Technique --- p.20 / Chapter 2.2 --- Sample Preparation --- p.22 / Chapter 2.2.1 --- Starting Material --- p.22 / Chapter 2.2.2 --- Proton Exchange Procedures --- p.23 / Chapter 2.2.3 --- Reverse Exchange Procedures --- p.23 / Chapter 2.3 --- Reference --- p.24 / Chapter Chapter 3 --- Time-of-Flight Ion Scattering and Recoiling Spectrometry (TOF-SARS) --- p.26 / Chapter 3.1 --- Introduction --- p.26 / Chapter 3.1.1 --- Physics in Elemental Analysis --- p.26 / Chapter 3.1.2 --- Physics in Structural Analysis --- p.29 / Chapter 3.2 --- Instrumentation --- p.32 / Chapter 3.2.1 --- Vacuum Chamber --- p.33 / Chapter 3.2.2 --- Pumping System --- p.35 / Chapter 3.2.3 --- Sample Manipulator --- p.35 / Chapter 3.2.4 --- Pulsed Ion Beam Line --- p.36 / Chapter 3.2.5 --- Detectors and Associated Electronics --- p.37 / Chapter 3.3 --- Reference --- p.39 / Chapter Chapter 4 --- Other Surface Science Tools Used in This Work --- p.41 / Chapter 4.1 --- Fourier Transform Infrared Spectroscopy (FTIR) --- p.41 / Chapter 4.1.1 --- Principle of FTIR --- p.41 / Chapter 4.1.2 --- Experiment --- p.42 / Chapter 4.1.3 --- Attenuated Total Reflectance (ATR) Mode of FTIR --- p.44 / Chapter 4.2 --- X-Ray Photoelectron Spectroscopy (XPS) --- p.45 / Chapter 4.2.1 --- Basic Principle of XPS --- p.45 / Chapter 4.2.2 --- Experimental Set Up --- p.48 / Chapter 4.3 --- Elastic Recoil Detection (ERD) --- p.49 / Chapter 4.3.1 --- Basic Theory of ERD --- p.49 / Chapter 4.3.2 --- Experimental Set Up --- p.50 / Chapter 4.4 --- Scanning Electron Microscope (SEM) --- p.51 / Chapter 4.4.1 --- Working Principle of SEM --- p.52 / Chapter 4.4.2 --- Experimental Set Up --- p.52 / Chapter 4.5 --- Reference --- p.53 / Chapter Chapter 5 --- Results and Discussions --- p.54 / Chapter 5.1 --- ERD Results on Incorporation of Protons --- p.54 / Chapter 5.2 --- XPS Results on Proton Exchange and Reverse Exchange --- p.56 / Chapter 5.3 --- FTIR Results on Proton Exchange and Reverse Exchange --- p.57 / Chapter 5.4 --- SEM Results on Domain-Inversion Induced by Proton Exchange --- p.59 / Chapter 5.5 --- TOF-SARS Results on Enhancement of Ion-induced Electron Emission by Proton Exchange --- p.61 / Chapter 5.5.1 --- Typical TOF-SARS Spectra - Data from Molybdenum Sample (Mo) Holder --- p.61 / Chapter 5.5.2 --- Virgin LiTa03 (0001) --- p.62 / Chapter 5.5.3 --- Possible Mechanism for the Variation of O(S) and the Electron Emission Yield --- p.65 / Chapter 5.5.4 --- The Use of O(S) Peak to Calculate the Potential Built Up upon a Change of Temperature --- p.67 / Chapter 5.5.5 --- TOF-SARS Data from the Proton and Lithium-ion Exchanged LiTa03 (0001) --- p.69 / Chapter 5.5.6 --- Plausible Mechanisms of Enhancement of Ion-induced Electron Yield induced by Proton Exchange --- p.70 / Chapter 5.6 --- Additional Discussions of the TOF-SARS Data on LiTa03 and Other Relevant Experiments --- p.75 / Chapter 5.6.1 --- Additional Discussion of the Nature of the Electron Peaks --- p.75 / Chapter 5.6.2 --- Additional Experiments on Azimuthal Angle (δ) Scans --- p.77 / Chapter 5.6.2.1 --- Data from Platinum (Pt) (111) as a Reference Test --- p.77 / Chapter 5.6.2.2 --- Azimuthal Angle Dependence of Ion-induced Electron Emission from Proton-ion Exchanged LiTa03 (0001) --- p.78 / Chapter 5.7 --- Reference --- p.80 / Chapter Chapter 6 --- Conclusion --- p.83 / Chapter Chapter 7 --- Appendix --- p.86 / Chapter 7.1 --- Caption --- p.86 / Chapter 7.2 --- Figures --- p.90

Abstract not available

Surface-analysis and treatment apparatus have been variously designed, manufactured, developed, and commissioned or re-commissioned, for characterising the surfaces and efficiency of positron moderators based around 3 µm thick polycrystalline-tungsten foil. These include XPS and AES, based around a CLAM2 hemispherical analyser, electron-beam heating, ion bombardment, mass spectroscopy, UHV sample mounting, UHV manipulation, gas-handling lines, and entry-lock apparatus. The CLAM2 electron spectrometer is additionally adapted for operation as a bipolar charged-particle spectrometer. All control software, and much data-analysis software, is implemented in Labview. Apparatus and techniques for safely storing, handling, transferring into vacuum, and manipulating in vacuo, a nominally 1 mCi 22Na, UHV-compatible positron source, are designed, constructed, and implemented. The efficacy of cleaning and surface-analysis apparatus are demonstrated, with some limitations and instrument malfunction identified, and solutions implemented. Methods for passivating positron-trapping states in polycrystalline tungsten are proposed, based on the current understanding of positron moderation and trapping. Improved moderator geometries have been designed and an alternative, simpler, and easier to implement solid-gas moderator proposed.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Materials Science and Engineering Program, 2006. / Includes bibliographical references.