Luo Yilun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 87-91). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Organization --- p.3 / Chapter 2. --- Architecture of MAG-μIMU --- p.5 / Chapter 2.1. --- Hardware for Attitude Filter --- p.5 / Chapter 2.2. --- Handwriting Recording for a Digital Writing Instrument --- p.7 / Chapter 3. --- Inertial Tracking for Handwriting --- p.9 / Chapter 3.1. --- Spatial Descriptions and Transformations --- p.9 / Chapter 3.1.1. --- Vector Description and Position of a Frame --- p.9 / Chapter 3.1.2. --- Coordinate Transformation and Orientation of a Frame --- p.10 / Chapter 3.1.3. --- Kinematics for Digital Writing Instruments --- p.12 / Chapter 3.1.4. --- Vector Rotation --- p.16 / Chapter 3.2. --- Euler Angles for Rotation in Space --- p.17 / Chapter 3.3. --- Euler Angles Attitude Kinematics --- p.19 / Chapter 3.4. --- Singular Problem --- p.19 / Chapter 4. --- Attitude in Quaternion --- p.22 / Chapter 4.1. --- Quaternion Operations --- p.22 / Chapter 4.1.1. --- Quaternion Conjugate --- p.23 / Chapter 4.1.2. --- Quaternion Norm --- p.24 / Chapter 4.1.3. --- Quaternion Inverse --- p.24 / Chapter 4.2. --- Orientation Description in Quaternion --- p.24 / Chapter 4.3. --- Attitude Kinematics in Quaternion --- p.25 / Chapter 5. --- Kalman Filter --- p.27 / Chapter 5.1. --- Time Update --- p.28 / Chapter 5.2. --- Measurement Update --- p.29 / Chapter 5.2.1. --- Maximum a Posterior Probability --- p.29 / Chapter 5.2.2. --- Batch Least-Square Estimation --- p.31 / Chapter 5.2.3. --- Measurement Update in Kalman Filter --- p.34 / Chapter 5.3. --- Kalman Filter Summary --- p.36 / Chapter 6. --- Extended Kalman Filter --- p.38 / Chapter 7. --- Attitude Extended Kalman Filter --- p.41 / Chapter 7.1. --- Time Update Model --- p.41 / Chapter 7.1.1. --- Attitude Strapdown Theory for a Quaternion --- p.41 / Chapter 7.1.2. --- Error Model for Time Update --- p.42 / Chapter 7.2. --- Measurement Update Model --- p.43 / Chapter 7.2.1. --- Error Model for the Measurement Update --- p.45 / Chapter 7.3. --- Summary --- p.46 / Chapter 8. --- Experiment Results --- p.47 / Chapter 8.1. --- Experiment for Attitude EKF based on MAG-μIMU --- p.47 / Chapter 8.1.1. --- Simulation Test --- p.48 / Chapter 8.1.2. --- Experiment Test --- p.49 / Chapter 8.2. --- Writing Application based on Attitude EKF Compensation --- p.52 / Chapter 8.2.1. --- Stroke Segment Kalman Filter --- p.54 / Chapter 8.2.2. --- Zero Velocity Compensation --- p.58 / Chapter 8.2.3. --- Complementary Attitude EKF for Writing Experiment --- p.60 / Chapter 9. --- Future Work --- p.73 / Chapter 9.1. --- Unscented Kalman Filter --- p.73 / Chapter 9.1.1. --- Least-square Estimator Structure --- p.73 / Chapter 9.1.2. --- Unscented Transform --- p.74 / Chapter 9.1.3. --- Unscented Kalman Filter --- p.76 / Chapter 9.2. --- Experiment Result --- p.81 / Chapter 10. --- Conclusion --- p.85 / Chapter 10.1. --- Attitude Extended Kalman Filter --- p.85 / Chapter 10.2. --- Complementary Attitude EKF --- p.85 / Chapter 10.3. --- Unscented Kalman Filter --- p.86 / Chapter 10.4. --- Future Work --- p.86 / Bibliography --- p.87 / Appendix A --- p.92

近年來微型製冷系統有許多應用。例如，電子器件的冷却是研製更快速、更小型和更可靠的芯片的重要課題, 隨著電子芯片功耗的增加，散熱量不断增長，傳統的被動式散熱方法已經過時，新的主動式散熱方法成爲必須。又例如微型個人冷卻系統可用於救火等各種惡劣環境。与其它製冷方法相比，蒸氣壓縮製冷技術是最有潜力的方法。 / 本文闡述了两种微型蒸氣壓縮製冷系統的研製工作：一是電子冷却系统，一是個人热舒适系统。研究主要包括以下幾個方面： / 1) 微型蒸氣壓縮製冷系統的熱力學分析。對系統在不同工作條件下（包括壓縮機效率、環境溫度等）的性能進行了分析。对換熱器的設計也作了详述。 / 2) 微型蒸氣壓縮製冷系統的熵分析。通過分析發現，壓縮機和系統漏熱造成的熵是產生系統不可逆性的主要因素,因此高效的壓縮機和降低系統漏熱是提高微型蒸氣壓縮製冷系統性能的關鍵所在。 / 3) 實驗系统的詳細介紹。一共做了两套微型蒸氣壓縮製冷系統，一为電子冷卻系統和一为個人冷卻系統。爲了縮小微型蒸氣壓縮製冷系統的尺寸，系統的元件必須小型化。系統的壓縮機是在市場上直接购買的，但是換熱器包括冷板蒸發器、管翅式蒸發器和微通道冷凝器都是特別設計和製造的。實驗裝置建成可以方便的改變工作條件，諸如壓縮機轉速、製冷劑充灌量、毛細管長度、換熱器面積等。 / 4) 對電子冷卻系統和個人冷卻系統分別進行了實驗。對於電子散熱系統來，當發熱管的功率為200瓦時，冷板溫度可以控制在大約60攝氏度。系統的熱力學完善度在0.23到0.31，而壓縮機的效率介乎40%至65%。對個人冷卻系統來，系統製冷量可達321瓦，其性能係數達到4.59。系統的熱力學完善度為0.21 ~ 0.27。 兩种系統的熱力學完善度都與當前家用製冷系统的熱力學完善度相似。相信不久的将来会有不少应用。 / Micro refrigeration systems are being increasingly used nowadays. One example is electronic cooling. With the rapid advancement of chips, traditional passive heat dissipation techniques are becoming obsolete and hence, new active cooling techniques become necessary. The other example is the personal thermal comfort system demanded by people working in the hazardous environment, such as fire fighting. Among various cooling methods, Vapor Compression Refrigeration (VCR) is the most promising method. According literatures, however, few miniature refrigeration systems are available. / This thesis presents two Miniature Vapor Compression Refrigeration (MVCR) systems, one for electronics cooling and the other for personal thermal comfort. In particularly, following aspects are focused: / 1) Thermodynamic analysis. The thermodynamic models of the systems are developed and the performances are studied under various working conditions including compressor efficiencies, ambient temperature and so on. / 2) Entropy analysis. It is found that entropy of the compressor and the heat leakage play crucial roles. High efficient compressor and the heat leakage minimization are very important. / 3) Prototype building. Two prototypes are built: one for electronics cooling and the other for personal thermal comfort. The miniature compressors are purchased from market. The heat exchangers, including the cold pate, tube-fin evaporator and micro channel condenser, are custom designed and made. / 4) Experiment testing. The two prototypes are tested under various working conditions such as compressor speed, refrigerant charge and capillary tube length. For the electronics cooling system, the cold plate temperature could be maintained at about 60 ºC under the 200 W heater power input. The second-law efficiency of the system varies from 0.23 to 0.31; and the compressor efficiency is between 40% ~ 65%. For the personal thermal comfort system, its capacity could reach 321 W with 100 g refrigerant charge, 1200 mm capillary tube length, and the compressor speed of 4503 rpm. The COP is 4.59 and the second-law efficiency is between 0.21 ~ 0.27. The performances of the two systems are comparable to that of the current domestic refrigeration systems. Therefore, it is expected that they will find some practical applications in the near future. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wu, Zhihui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 99-110). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.I / Acknowledgement --- p.IV / List of Tables --- p.VIII / List of Figures --- p.IX / Nomenclature --- p.XII / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Backgound --- p.1 / Chapter 1.2 --- Thesis Outline --- p.5 / Chapter Chapter 2 --- Literature Review --- p.6 / Chapter 2.1 --- History of Refrigeration --- p.6 / Chapter 2.2 --- Availabe Refrigeration Methods --- p.7 / Chapter 2.2.1 --- Heat pipe and vapor chamber --- p.9 / Chapter 2.2.2 --- Thermoelectric cooler --- p.10 / Chapter 2.2.3 --- Stirling refrigerator --- p.10 / Chapter 2.2.4 --- Pulse tube refrigerator --- p.11 / Chapter 2.2.5 --- Absorption refrigerator --- p.12 / Chapter 2.3 --- Vapor Compression Refrigeration System --- p.14 / Chapter 2.3.1 --- Development of the miniature refrigeration system --- p.15 / Chapter 2.3.2 --- Development of the miniature compressors --- p.20 / Chapter 2.3.3 --- Development of the micro heat exchangers --- p.24 / Chapter 2.3.4 --- Applications --- p.28 / Chapter Chapter 3 --- System Analsysis and Components Design --- p.29 / Chapter 3.1 --- A Brief Review of a Typical VCR System --- p.29 / Chapter 3.1.1 --- Refrigerant comparison --- p.33 / Chapter 3.1.2 --- Effect of the compressor efficiency --- p.34 / Chapter 3.1.3 --- Effect of the ambient temperature --- p.35 / Chapter 3.1.4 --- Effect of the evaporator temperature --- p.36 / Chapter 3.2 --- Analysis on Entropy Generation of a MVCR System --- p.37 / Chapter 3.2.1 --- Derivation of coefficient of performance --- p.38 / Chapter 3.2.2 --- Entropy generation calculation for a MVCR system --- p.39 / Chapter 3.3 --- System Design --- p.46 / Chapter 3.3.1 --- System Configuration --- p.46 / Chapter 3.3.2 --- Heat Exchanger Design --- p.47 / Chapter 3.3.2.1 --- Condenser design --- p.48 / Chapter 3.3.2.2 --- Cold plate design --- p.50 / Chapter 3.3.2.3 --- Tube-fin evaporator design --- p.51 / Chapter Chapter 4 --- The MVCR System for Electronics Cooling --- p.55 / Chapter 4.1 --- Experimental Setup --- p.55 / Chapter 4.1.1 --- Components --- p.55 / Chapter 4.1.2 --- Instrumentation --- p.61 / Chapter 4.1.3 --- Testing plans --- p.63 / Chapter 4.1.4 --- Data reduction --- p.64 / Chapter 4.1.5 --- Uncertainty analysis --- p.67 / Chapter 4.2 --- Results and Discussion --- p.68 / Chapter 4.2.1 --- Effect of the compressor speed --- p.68 / Chapter 4.2.2 --- Effect of the refrigerant charge --- p.70 / Chapter 4.2.3 --- Effect of the capillary tube length --- p.71 / Chapter 4.2.4 --- Cold plate temperature comparison --- p.72 / Chapter 4.2.5 --- Location of the Cartridge heater --- p.76 / Chapter 4.2.6 --- System efficiency --- p.78 / Chapter 4.2.7 --- Thermal resistance --- p.81 / Chapter 4.3 --- Summary --- p.83 / Chapter Chapter 5 --- The MVCR System for Personal Cooling --- p.85 / Chapter 5.1 --- Experimental Setup --- p.85 / Chapter 5.2 --- Results and Discussions --- p.87 / Chapter 5.2.1 --- Effect of the compressor speed --- p.87 / Chapter 5.2.2 --- Effect of the refrigerant charge --- p.88 / Chapter 5.2.3 --- Effect of the capillary tube length --- p.89 / Chapter 5.2.4 --- Effect of the evaporator area --- p.90 / Chapter 5.2.5 --- Effect of the evaporator fan speed --- p.91 / Chapter 5.2.6 --- System efficiency --- p.92 / Chapter 5.3 --- Summary --- p.94 / Chapter Chapter 6 --- Conclusions and Future Work --- p.96 / Chapter 6.1 --- Conclusions --- p.96 / Chapter 6.2 --- Future Work --- p.98 / Bibliography --- p.99

Chan, Ngai Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 67-70). / Abstracts in English and Chinese. / Abstract --- p.I / 摘要 --- p.III / List of Figures --- p.VI / List of Tables --- p.VIII / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background Information --- p.2 / Chapter 1.1.1 --- Project Background --- p.2 / Chapter 1.1.2 --- Literature Review --- p.4 / Chapter 1.1.3 --- Background on Gear Hobbing --- p.10 / Chapter 1.1.4 --- Traditional gear hobbing machines --- p.12 / Chapter 2 --- Design and Testing of the MMT system --- p.15 / Chapter 2.1 --- Specifications of the MMT system --- p.16 / Chapter 2.1.1 --- Overall Configuration --- p.18 / Chapter 2.1.2 --- Linear Actuation --- p.18 / Chapter 2.1.3 --- Main Spindle Assembly --- p.19 / Chapter 2.1.4 --- Tool Plate Assembly --- p.20 / Chapter 2.1.5 --- Motion Control --- p.22 / Chapter 2.2 --- Main Features --- p.24 / Chapter 2.2.1 --- Mechanically Decoupled Gear Hobbing --- p.24 / Chapter 2.2.2 --- Single Setup for Non-planar Gears --- p.26 / Chapter 2.2.3 --- Quality Assurance by Computer Simulation --- p.27 / Chapter 2.3 --- Turning Test --- p.28 / Chapter 2.3.1 --- Experiment Results --- p.29 / Chapter 2.3.2 --- Tornos' Performance --- p.30 / Chapter 2.3.3 --- Estimation of Cutting Force and Workpiece Deflection --- p.32 / Chapter 2.4 --- Synchronization Test --- p.33 / Chapter 2.4.1 --- Experimental Results --- p.34 / Chapter 2.5 --- Gear Hobbing Test --- p.36 / Chapter 3 --- Diagnostic Tool: Gear Hobbing Simulation --- p.40 / Chapter 3.1 --- Simulation Model --- p.41 / Chapter 3.2 --- Simulations with Process Defects --- p.44 / Chapter 3.2.1 --- Asynchronous motion between tool and workpiece spindle --- p.44 / Chapter 3.2.2 --- Pitch error of the cutter hob --- p.45 / Chapter 3.2.3 --- Tool spindle run-out error --- p.47 / Chapter 3.2.4 --- Combination of process defects --- p.49 / Chapter 3.3 --- Experiment Validation --- p.50 / Chapter 4 --- Technical know-hows --- p.55 / Chapter 4.1 --- Premature Part Break-off --- p.55 / Chapter 4.2 --- Tool Alignment and Centering --- p.58 / Chapter 4.2.1 --- Two-turns Aligning Algorithm --- p.59 / Chapter 5 --- Conclusion and Future Work --- p.63 / References --- p.67 / Publication Record --- p.71 / Appendix --- p.72

Yip, Wai Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 119-124). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgement --- p.iii / Table of Content --- p.iv / List of Figure --- p.vi / List of table --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Background information --- p.2 / Chapter 1.2.1 --- Overview of positioning technologies --- p.2 / Chapter 1.2.2 --- Comparison between different positioning systems --- p.7 / Chapter 1.2.3 --- Recent works related to INS --- p.9 / Chapter 1.3 --- Objective --- p.11 / Chapter 1.4 --- Organization of thesis --- p.11 / Chapter Chapter 2 --- Literature Study --- p.13 / Chapter 2.1 --- Introduction to INS --- p.13 / Chapter 2.1.1 --- Coordinate Frames --- p.13 / Chapter 2.1.2 --- Gimbaled INS --- p.16 / Chapter 2.1.3 --- Strapdown INS --- p.17 / Chapter 2.1.4 --- Conventional algorithm of strapdown INS --- p.17 / Chapter 2.2 --- Inertial sensors --- p.19 / Chapter 2.2.1 --- Gyroscope --- p.19 / Chapter 2.2.2 --- Accelerometer --- p.20 / Chapter 2.3 --- Previous works --- p.22 / Chapter 2.4 --- GF-INS --- p.23 / Chapter 2.5 --- Summary --- p.25 / Chapter Chapter 3 --- Performance of MEMS accelerometer in position determination --- p.27 / Chapter 3.1 --- Basic principle --- p.27 / Chapter 3.2 --- Numeric integration --- p.28 / Chapter 3.3 --- Experimental setup --- p.30 / Chapter 3.3.1 --- MEMS Accelerometer --- p.30 / Chapter 3.3.2 --- Microcontroller --- p.32 / Chapter 3.3.3 --- System architecture --- p.33 / Chapter 3.3.4 --- Testing platform --- p.34 / Chapter 3.4 --- Initial calibration and filtering --- p.37 / Chapter 3.4.1 --- Convert ADC reading to acceleration --- p.37 / Chapter 3.4.2 --- Identify configuration error --- p.38 / Chapter 3.4.3 --- Implement low pass filter --- p.39 / Chapter 3.5 --- Experimental results --- p.40 / Chapter 3.5.1 --- Results --- p.40 / Chapter 3.5.2 --- Discussion --- p.43 / Chapter 3.6 --- Summary --- p.45 / Chapter Chapter 4 --- Performance Improvement --- p.46 / Chapter 4.1 --- Fuzzy logic based steady state detector --- p.46 / Chapter 4.1.1 --- Principle --- p.46 / Chapter 4.1.2 --- Experimental result --- p.48 / Chapter 4.2 --- Kalman filtering --- p.50 / Chapter 4.2.1 --- Discrete Kalman filter --- p.50 / Chapter 4.2.2 --- Combine with fuzzy logic based steady state detector --- p.52 / Chapter 4.2.3 --- Experimental results --- p.54 / Chapter 4.3 --- Summary --- p.58 / Chapter Chapter 5 --- Construction of GF-INS --- p.59 / Chapter 5.1 --- Principle of GF-INS --- p.59 / Chapter 5.1.1 --- Algorithm --- p.59 / Chapter 5.1.2 --- Comparing error of GF-INS and conventional INS --- p.66 / Chapter 5.1.3 --- Simulation study --- p.67 / Chapter 5.2 --- Experimental setup --- p.73 / Chapter 5.3 --- Experimental Results --- p.75 / Chapter 5.4 --- Summary --- p.81 / Chapter Chapter 6 --- Improvement on the GF-INS --- p.82 / Chapter 6.1 --- Configuration error compensation --- p.82 / Chapter 6.1.1 --- "Identify bias, scale factor and sensing direction error" --- p.83 / Chapter 6.1.2 --- Identify position error --- p.86 / Chapter 6.1.3 --- Compensator design --- p.89 / Chapter 6.1.4 --- Simulation --- p.91 / Chapter 6.2 --- Fuzzy rule based motion state detector --- p.97 / Chapter 6.2.1 --- Relation of data in different motions --- p.97 / Chapter 6.2.2 --- Fuzzy system --- p.99 / Chapter 6.2.3 --- Membership function training with gradient descent --- p.101 / Chapter 6.3 --- Experimental results and discussion --- p.104 / Chapter 6.3.1 --- Configuration errors --- p.104 / Chapter 6.3.2 --- Compensator --- p.106 / Chapter 6.3.3 --- Fuzzy rule based motion state detector --- p.107 / Chapter 6.3.4 --- Comparing the performance of both methods --- p.110 / Chapter 6.3.5 --- Comparing GF-INS and one dimensional INS --- p.112 / Chapter 6.3.6 --- Discussion --- p.113 / Chapter 6.4 --- Summary --- p.115 / Chapter Chapter 7 --- Conclusions and Future works --- p.116 / Reference --- p.119

Prior research focused on CMOS-MEMS integrated oscillator has been done using various foundry compatible integration techniques. In order to compensate the integration compatibility, MEMS resonators built on standard CMOS foundry process could not take full advantage of highest achievable quality factor on chip. System-in-package (SiP) and system-on-chip (SoC) is becoming the next generation of electronic packaging due to the need of multi-functional devices and multi-sensor systems, thus wafer level hybrid integration becomes the key to enable the full assembly of dissimilar devices. In this way, every active circuit and passive component can be individually optimized, so do the MEMS resonators and sustaining amplifier circuits. In this dissertation, GaAs-MEMS integrated oscillator in a hybrid packaging has been fully explored as an important functional block in the RF transceiver systems. This dissertation first presents design, micro-fabrication, simulation, testing and modeling of ZnO piezoelectrically-transduced MEMS resonators. A newly designed rectangular plate with curved resonator body fabricated in-house exhibits a very high Q of more 6,000 in the air for its width-extensional mode resonance at 166 MHz. In addition, a rectangular plate resonator with multiple Phononic Crystal (PC) strip tethers shows low insertion loss of -11.5 dB at 473.9 MHz with a Q of 2722.5 in the air. An oscillator technology with high-Q MEMS resonator as its tank circuit is presented to validate its key functionality as a stable frequency reference across a wide spectrum of frequencies. Particularly, a piezoelectrically-transduced width-extensional mode MEMS resonator is strategically designed to operate at two distinct layout-defined mechanical modal frequencies (259.5MHz and 436.7MHz). These devices were characterized and modeled by an extracted equivalent LCR circuit to facilitate the design of the oscillator using a standard circuit simulator. MEMS resonators have been integrated with the sustaining amplifier circuit at PCB level using wire-bonding technique and coaxial connectors. As shown by the time-domain measurements and frequency-domain measurements, these oscillators are capable of selectively locking into the resonance frequency of the tank circuit and generating a stable sinusoidal waveform. Meanwhile, the phase noise performance is rigorously investigated within a few oscillator designs. At last, 3-D printed hybrid packaging using additive manufacturing and laser machining technique has been developed for integrating a MEMS resonator on a silicon-on-insulator (SOI) substrate and a GaAs sustaining amplifier. Fabrication process and fundamental characterization of this hybrid packaging has been demonstrated. On-wafer probe measurements of a 50 Ω microstrip line on ABS substrate exhibit its insertion loss of 0.028 dB/mm at 5 GHz, 0.187 dB/mm at 20 GHz and 0.512 dB/mm at 30 GHz, and show satisfactory input and output return loss with the 3-D printed package. Parylene N is also experimentally coated on the package for improving water resistance as a form of hermetic packaging.

The goal of this research is to improve the structure and dimension of the MEMS acoustic emission sensor. Acoustic emission sensor (AE sensor) based on the piezoelectric transducer is a well-developed technology in non-destructive testing that is widely used to determine permanent damage such as cracks and corrosions in buildings and structures. The AE sensor can be used to monitor cracks in structures and to check leakage in pressurized systems. The location of cracks in a structure or system leakage causes a high-frequency surface vibration while releasing ultrasonic energy. The frequency of this energy is typically between 30 kHz to 1MHz. The AE sensor can detect this high frequency transient acoustic wave. By using this AE sensor, the structure and pressurized system can be monitored to generate an evaluation report in order to facilitate maintenance and structure repair. Currently, the commercial AE sensor is bulky because it is made of a piezoelectric transducer. It also needs a lot of wires to connect with the pre-amplifier and signal conditioning systems. Because of the cost, brittleness and the volume of the commercial AE sensor, new affordable AE sensor technology is desired to replace the commercial AE sensor. The new AE sensor should be economical, small, and lightweight. The performance of the output signal should be comparable with the commercial AE sensor in terms of signal strength and signal to noise ratio. The MEMS AE sensors provide the potential solution to this problem. The MEMS AE sensors can overcome the problems of the commercial AE sensor. The MEMS AE sensor combines the pre- amplifier on the chip in a single package. Through the MEMS technology, the AE sensor can be manufactured in mass quantity and high quality. This study focuses on simulating and measuring the performance of the MEMS acoustic emission sensors. Through simulation, the capacitance value is influenced by the gap between the suspended membrane (top perforated metal plate), metal ground, and also influenced by the effective area of the perforated top layer. The perforation is introduced to reduce the squeeze film damping effect. Through measurement verification, the MEMS AE sensors have exhibited comparable performance before and after inclusion of the 3D printed package that serves as the housing for the completed sensor assembly. The C-V measurement is the key method to extract the capacitance value, which is the key parameter to determine the signal strength and signal to noise ratio for capacitive MEMS acoustic emission sensors. The damping coefficient is also the key factor to receive the time domain measurement data in a fashion that resemble the bulky commercial piezoelectric AE transducers.

[Truncated abstract] This study investigates the mechanical and physical properties of low-temperature (100-300 ?C) plasma enhanced chemical vapour deposited (PECVD) silicon nitride (SiNxHy) thin films for the fabrication of short-wave infrared tunable Fabry-Perot filters with high fill factor, high cavity finesse and low actuation voltages. It has been the intensions of this work to fabricate a tunable filter that can be monolithically integrated with temperature-sensitive substrates, namely mercury cadmium telluride (Hg(1-x)CdxTe) photoconductors and photodiodes. A range of methods have been utilised to determine the Young's modulus (E), residual stress ([sigma]0), density ([rho]) and Poisson's ratio ([nu]) of PECVD SiNxHy thin films. In order to understand how E, [sigma]0, [rho] and [nu] are affected by process conditions, a range of SiNxHy thin films deposited with varying chuck temperatures, RF powers and chamber pressures were measured. The resonance method was used to determine E and [nu] of SiNxHy thin films deposited under varying process conditions. The resonance method involves exciting the bending and torsional vibration modes of a microcantilever beam fabricated from a film. The E and G values can be extracted directly from the bending and torsional vibration modes and the [nu] value can be determined from the calculated E and G values. The density of the films was determined using the quartz crystal microbalance method. In order to determine the validity of the resonance method, finite element modelling was used to determine its dependence on microcantilever beam dimensions. ... Increasing the temperature also increases the tensile residual stress of the films. This study also reveals that increasing the RF power and decreasing the chamber pressure increases E and [rho], as well as increasing the compressive residual stress of the films. The theoretical design and analysis, as well as the fabrication of a new surface micromachined short-wave infrared tunable Fabry-Perot filter for adaptive infrared photon detectors is also presented in this study. The proposed structure, termed the suspension filter, uses broad spectral range, high reflectivity distributed Bragg reflector (DBR) mirrors, resulting in very high finesse filters. The device utilises multiple sacrificial layers to define the resonant cavity spacer and the separation of the top mirror from the supporting flexures. The flexures were fabricated from low-temperature (PECVD) SiNxHy thin films. Separation of the top mirror from the supporting flexures allows for improved fill-factors (up to 79%), as well as increased tuning range. Theoretical optical and electromechanical results shows large wavelength tuning ranges (1.5-2.5 [mu]m) at low actuation voltages (<30 V) are possible using the proposed design, whilst still maintaining a high cavity finesse. Optical characterisation of fixed filter micro-cavities on Si substrates show transmissions of ~60% with small line widths (35 nm) are achievable using the proposed mirror system. Mirror displacement versus applied bias voltage curves obtained from a released filter fabricated on Si show a stable mirror displacement of 620 nm was achieved, whilst theoretical results suggested the required 750 nm mirror displacement is possible using the proposed design.

Cancer is a major health problem in the world today. Almost all cancers have a significantly better chance for therapy and recovery if detected at their early stage. The capability to perform disease diagnosis at an early stage requires high-resolution imaging that can visualise the physiological and morphological changes at a cellular level. However, resolving powers of current medical imaging systems are limited to sub-millimeter sizes. Furthermore, the majority of cancers are associated with morphological and functional alterations of cells in epithelial tissue, currently assessed by invasive and time-consuming biopsy. Optical imaging enables visualisations of tissue microstructures at the level of histology in non-invasive means. Optical imaging is suitable for detecting neoplastic changes with sub-cellular resolution in vivo without the need for biopsy. Nonlinear optical microscopy based on multi-photon absorption and higher harmonic generation has provided spectacular sights into visualisation of cellular events within live tissue due to advantages of an inherent sectioning ability, the relatively deep optical penetration, and the direct visualisation of intrinsic indicators. Two-photon excited uorescence (TPEF) from intrinsic cell components and second harmonic from asymmetric supermolecular structures can provide complementary information regarding functionalities and morphologies in tissue environments, thus enabling premalignant diagnosis by detecting the very earliest changes in cellular structures. During the past sixteen years, nonlinear optical microscopy has evolved from a photonic novelty to a well-established laboratory tool. At present, in vivo imaging and long-term bedside studies by use of nonlinear optical microscopy have been limited due to the fact that the lack of the compact nonlinear optical instrument/imaging technique forces the performance of nonlinear optical microscopy with bulk optics on the bench top. Rapid developments of fibre-optics components in terms of growing functionalities and decreasing sizes provide enormous opportunities for innovation in nonlinear optical microscopy. Fibre-based nonlinear optical endoscopy will be the soul instrumentation to permit the cellular imaging within hollow tissue tracts or solid organs that are inaccessible with a conventional optical microscope. Lots of efforts have been made for development of miniaturised nonlinear optical microscopy. However, there are major challenges remaining to create a nonlinear optical endoscope applicable within internal cavities of a body. First, an excitation laser beam with an ultrashort pulse width should be delivered eciently to a remote place where ecient collection of faint nonlinear optical signals from biological samples is required. Second, laser-scanning mechanisms adopted in such a miniaturised instrumentation should permit size reduction to a millimeter scale and enable fast scanning rates for monitoring biological processes. Finally, the design of a nonlinear optical endoscope based on micro-optics must maintain great exibility and compact size to be incorporated into endoscopes to image internal organs. Although there are obvious diculties, development of fibre-optic nonlinear optical microscopy/endoscopy would be indispensible to innovate conventional nonlinear optical microscopy, and therefore make a significant impact on medical diagnosis. The work conducted in this thesis demonstrates the new capability of nonlinear optical endoscopy based on a single-mode fibre (SMF) coupler or a double-clad photonic crystal fibre (PCF), a microelectromechanical system (MEMS) mirror, and a gradientindex (GRIN) lens. The feasibility of all-fibre nonlinear optical endoscopy is also demonstrated by the further integration of a double-clad PCF coupler. The thesis concentrates on the following key areas in order to exploit and understand the new imaging modality. It has been known from the previous studies that an SMF coupler is suitable for twoii photon excitation by transmitting near infrared illumination and collecting uorescence at visible wavelength as well. Although second harmonic generation (SHG) wavelength is farther away from the designed wavelength of the fibre coupler than that of normal TPEF, it is demonstrated in this thesis that both SHG and TPEF signals can be collected simultaneously and eciently through an SMF coupler with axial resolution of 1.8 um and 2.1 um, respectively. The fibre coupler shows a unique feature of linear polarisation preservation along the birefringent axis over the near infrared and the visible wavelength regions. Therefore, SHG polarisation anisotropy can be potentially extracted for probing the orientation of structural proteins in tissue. Furthermore, this thesis shows the characterisation of nonlinear optical microscopy based on the separation distance of an SMF coupler and a GRIN lens. Consequently, the collection of nonlinear signals has been optimised after the investigation of the intrinsic trade-off between signal level and axial resolution. These phenomena have been theoretically explored in this thesis through formalisation and numerical analysis of the three-dimensional (3D) coherent transfer function for a SHG microscope based on an SMF coupler. It has been discovered that a fibreoptic SHG microscope exhibits the same spatial frequency passband as that of a fibreoptic reection-mode non-uorescence microscope. When the numerical aperture of the fibre is much larger than the convergent angle of the illumination on the fibre aperture, the performance of fibre-optic SHG microscopy behaves as confocal SHG microscopy. Furthermore, it has been shown in both analysis and experiments that axial resolution in fibre-optic SHG microscopy is dependent on the normalised fibre spot size parameters. For a given illumination wavelength, axial resolution has an improvement of approximately 7% compared with TPEF microscopy using an SMF coupler. Although an SMF enables the delivery of a high quality laser beam and an enhanced sectioning capability, the low numerical aperture and the finite core size of an SMF give rise to a restricted sensitivity of a nonlinear optical microscope system. The key innovation demonstrated in this thesis is a significant signal enhancement of a nonlinear optical endoscope by use of a double-clad PCF. This thesis has characterised properties of our custom-designed double-clad PCF in order to construct a 3D nonlinear optical microscope. It has been shown that both the TPEF and SHG signal levels in a PCF-based system that has an optical sectioning property for 3D imaging can be significantly improved by two orders of magnitude in comparison with those in an SMF-based microscope. Furthermore, in contrast with the system using an SMF, simultaneous optimisations of axial resolution and signal level can be obtained by use of double-clad PCFs. More importantly, using a MEMS mirror as the scanning unit and a GRIN lens to produce a fast scanning focal spot, the concept of nonlinear optical endoscopy based on a double-clad PCF, a MEMS mirror and a GRIN lens has been experimentally demonstrated. The ability of the nonlinear optical endoscope to perform high-resolution 3D imaging in deep tissue has also been shown. A novel three-port double-clad PCF coupler has been developed in this thesis to achieve self-alignment and further replace bulk optics for an all-fibre endoscopic system. The double-clad PCF coupler exhibits the property of splitting the laser power as well as the separation of a near infrared single-mode beam from a visible multimode beam, showing advantages for compact nonlinear optical microscopy that cannot be achieved from an SMF coupler. A compact nonlinear optical microscope based on the doubleclad PCF coupler has been constructed in conjunction with a GRIN lens, demonstrating high-resolution 3D TPEF and SHG images with the axial resolution of approximately 10 m. Such a PCF coupler can be useful not only for a fibre-optic nonlinear optical probe but also for double-clad fibre lasers and amplifiers. The work presented in this thesis has led to the possibility of a new imaging device to complement current non-invasive imaging techniques and optical biopsy for cancer detection if an ultrashort-pulsed fibre laser is integrated and the commercialisation of the system is achieved. This technology will enable in vivo visualisations of functional and morphological changes of tissue at the microscopic level rather than direct observations with a traditional instrument at the macroscopic level. One can anticipate the progress in bre-optic nonlinear optical imaging that will propel imaging applications that require both miniaturisation and great functionality.

Thesis (M.S.)--State University of New York at Binghamton, Department of Mechanical Engineering, 2006. / Includes bibliographical references.

An overview is provided of materials and processes research currently being conducted in support of MEMS device design at MIT. Underpinning research is being conducted in five areas: room temperature strength characterization, elevated temperature strength characterization, processing of Si/SiC hybrid structures, modeling of wafer bonding processes and development of high temperature fluid interconnections. Emphasis is placed on the key areas of materials science and engineering. / Singapore-MIT Alliance (SMA)