No description available.

No description available.

Sun Winston. / "December 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (p. 149-159). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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Ng Tsz Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 67-70). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.ii / ACKNOWLEDGEMENTS --- p.iii / LIST OF FIGURES --- p.iv / LIST OF TABLES --- p.ix / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Literature Review --- p.3 / Chapter 1.3 --- Research Objectives --- p.5 / Chapter 1.4 --- Thesis Organization --- p.5 / Chapter CHAPTER 2 --- MODELING OF PIEZOELECTRIC SENSOR/GENERATOR --- p.6 / Chapter 2.1 --- Constitutive Equations --- p.6 / Chapter 2.2 --- Voltage Output of Piezoelectric Materials --- p.9 / Chapter 2.2.1 --- Short Circuit --- p.9 / Chapter 2.2.2 --- Open Circuit --- p.11 / Chapter 2.3 --- Sensitivity and Power Generation --- p.13 / Chapter 2.4 --- Modeling and Analysis of Sensor Structure --- p.23 / Chapter 2.4.1 --- Damping Ratio Estimation --- p.25 / Chapter (a) --- Half-power bandwidth method --- p.25 / Chapter (b) --- Linear interpolation method --- p.25 / Chapter 2.4.2 --- Trade-off between Resonant Frequency and Output Sensitivity of a Sensor --- p.29 / Chapter (a) --- Maximize Sme with constant wn --- p.31 / Chapter (b) --- Maximize wn with constant Sme --- p.33 / Chapter 2.5 --- Model Accuracy --- p.39 / Chapter CHAPTER 3 --- POWER HARVESTING --- p.41 / Chapter 3.1 --- Circuit Model --- p.41 / Chapter 3.2 --- Energy Storage --- p.47 / Chapter 3.3 --- Size Effect on Power Output --- p.49 / Chapter 3.4 --- Power Harvesting Circuit --- p.50 / Chapter 3.4.1 --- Performance of the Power Harvesting Circuit --- p.51 / Chapter (a) --- Power Harvesting Circuit Efficiency --- p.52 / Chapter (b) --- Useful Power Output --- p.53 / Chapter (c) --- System Efficiency --- p.56 / Chapter (d) --- Relationship between Input Excitation and Charge Time --- p.57 / Chapter 3.5 --- Harvested Energy for Wireless Transmission --- p.60 / Chapter CHAPTER 4 --- CONCLUDING REMARKS --- p.64 / Chapter 4.1 --- Sensor/Generator Design --- p.64 / Chapter 4.2 --- Potential Applications --- p.64 / Chapter 4.3 --- Conclusion --- p.65 / Chapter 4.4 --- Future Work --- p.66 / REFERENCES --- p.67 / APPENDIX --- p.71

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

No description available.

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

In addition, this project also investigated schemes that might enhance the phase change in the SPR sensor. The "double-pass" and "multi-pass" approaches through which the SPR phase can be amplified upon hitting the sensor surface more than once, have been experimentally studied and successfully demonstrated. A double-pass method can immediately offer two times of phase change as compared to the singlepass one. Accordingly the multi-pass scheme offers a higher then two times phase enhancement. Such improvement in phase detection is extremely important for biosensing applications involving small molecules, small proteins, DNA and etc. Another approach for detection performance improvement is to incorporate a multilayer configuration for the biosensing surface. In order to improve the dynamic measurement response, we proposed to use a multiple resonant angle measurement approach in conjunction with the single-beam self-referenced phase-sensitive SPR configuration. With the use of many multiple incident angles, the system provided sensing capability that covers a refractive index (RI) 1.33 to over 1.38. A 128-element array detector was employed to measure the resonance phase change over the range of the incident angles to ensure a reasonably continuous phase response curves achievable from the system. / This project is concerned with the development and optimization of optical sensors based on measuring the phase change of surface plasmon resonance (SPR) effect. The phase sensitive SPR technique provides very high sensitivity performance due to the fact that an abrupt phase jump occurs near the resonance dip, thus resulting in large phase shift with very small change in the sensing medium. A range of different measurement techniques for enhancing system sensitivity have been investigated. Moreover we also studied the phase change characteristics around the SPR dip region by means of simulation in order to explore various approaches for achieving further improvement in sensitivity and as well as wide dynamic range. Since SPR is caused by electron charge density oscillations in metal surface in which the wave momentum required for plasmon wave excitation is always larger than that for free space, an inverted prism-coupling scheme (prism-metal-dielectric) is commonly used and this configuration was also employed in our experimental setup, particularly for the SPR biosensor based on differential phase Mach-Zehnder interferometer configuration. This design primarily operates by taking advantage of the fact that SPR only affects the p-polarization while leaving the s-polarization unchanged. This means that differential phase measurement between the p- and s- polarizations will result in SPR signals that are completely free from any disturbances that are common to both channels. Experimental results obtained from glycerin/water mixtures indicate that the sensitivity limit of our scheme is 5.48 x 10 -8 refractive index unit per 0.01° phase change. To our knowledge, this is a significant improvement over previously obtained results when gold is used as the sensor surface. While acknowledging that accurate optical alignment is a crucial requirement for the Mach-Zehnder interferometer and it is often not easy to maintain high degree alignment accuracies in practical situations, we have developed a versatile and low cost single-beam self-referenced phase-sensitive surface SPR sensing system. The system exhibits a root-mean-square phase fluctuation of +/-0.0028° over a period of 45 minutes, i.e. a resolution of +/-5.2x10 -9 refractive index units. The enhanced performance has been achieved through the incorporation of three design elements: (i) a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected; (ii) a differential measurement scheme to eliminate spurious signals not related to the sensor response; (iii) elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulator. Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional florescence-based techniques. / Wu, Shu Yuen. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 132-147). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.