Fung, Kar Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 110-114). / Abstracts in English and Chinese. / 摘要 --- p.i / ABSTRACT --- p.ii / ACKNOWLEDGMENTS --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF FIGURES --- p.vi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Background and Motivation --- p.1 / Chapter 1.2 --- Objective of the project --- p.4 / Chapter 1.3 --- Organization of the thesis --- p.5 / Chapter 2. --- Literature Review --- p.7 / Chapter 2.1 --- Control on Micro-Manipulation --- p.7 / Chapter 2.1.1 --- Visual Feedback Control --- p.8 / Chapter 2.1.2 --- Sensor-Based Feedback Control --- p.9 / Chapter 2.1.3 --- Bilateral Control --- p.9 / Chapter 2.2 --- Force Sensing System on Micro-Manipulation --- p.10 / Chapter 2.3 --- PVDF Sensor --- p.11 / Chapter 2.4 --- Summary of the Literature Review --- p.12 / Chapter 3. --- Micro-Manipulation --- p.14 / Chapter 3.1 --- Introduction of Micro-Manipulation --- p.14 / Chapter 3.2 --- Probe Station --- p.14 / Chapter 3.2.1 --- Micromanipulators --- p.15 / Chapter 3.2.2 --- Microscopes --- p.15 / Chapter 4. --- Piezoelectric Polyvinylidence Fluoride (PVDF) Sensor --- p.16 / Chapter 4.1 --- Charteristic of PVDF Sensor --- p.16 / Chapter 4.1.1 --- Piezoelectric Properties --- p.16 / Chapter 4.1.2 --- Dimensions of the PVDF Sensor --- p.18 / Chapter 4.2 --- Comparison of Piezoelectric Materials --- p.19 / Chapter 5. --- Theoretical Analysis of PVDF Sensor --- p.21 / Chapter 5.1 --- Sensitivity of PVDF Sensor --- p.21 / Chapter 5.2 --- Relationship between the Deflection and the Force of the PVDF --- p.22 / Chapter 5.3 --- Calculation of the Spring Constant K of the PVDF --- p.23 / Chapter 5.4 --- Simulation on the output from the PVDF Sensor --- p.23 / Chapter 6. --- Experimental Analysis of PVDF Sensor --- p.26 / Chapter 6.1 --- Force-Deflection Diagram --- p.26 / Chapter 6.2 --- Frequency Response of the PVDF Sensor --- p.27 / Chapter 7. --- 1-D PVDF-Based Sensing System --- p.30 / Chapter 7.1 --- Original Design of the Sensing System --- p.30 / Chapter 7.1.1 --- Plastic pipe and adapter --- p.31 / Chapter 7.1.2 --- PVDF Sensor --- p.32 / Chapter 7.1.3 --- Probe-tip holder --- p.32 / Chapter 7.2 --- Current Design of the Sensing System --- p.32 / Chapter 7.3 --- Analysis of the Sensing System --- p.34 / Chapter 7.3.1 --- Frequency Response of the Sensing System --- p.34 / Chapter 7.3.2 --- Sensitivity of the Sensing System --- p.41 / Chapter 8. --- Experiments on 1-D PVDF Sensing System --- p.49 / Chapter 8.1 --- Experimental Setup of the 1-D Sensing System --- p.49 / Chapter 8.1.1 --- Programmable Micromanipulator --- p.50 / Chapter 8.1.2 --- Charge Amplifier --- p.51 / Chapter 8.2 --- Calibration of the 1-D Sensing System --- p.53 / Chapter 8.2.1 --- Noise Signal from the system --- p.53 / Chapter 8.2.2 --- Signal from vibration --- p.55 / Chapter 8.3 --- Experimental Results on touching a substrate --- p.60 / Chapter 8.3.1 --- Description --- p.60 / Chapter 8.3.2 --- Results from touching a substrate --- p.62 / Chapter 8.3.3 --- Analysis of the deflection after touched a substrate --- p.67 / Chapter 8.4 --- Experimental Results on touching a micro mirror --- p.68 / Chapter 8.4.1 --- Description --- p.68 / Chapter 8.4.2 --- Results --- p.70 / Chapter 8.5 --- Experimental Results on lifting a mass platform --- p.74 / Chapter 8.5.1 --- Description --- p.74 / Chapter 8.5.2 --- Results --- p.76 / Chapter 9. --- Modification of 1-D Sensing System --- p.79 / Chapter 9.1 --- Design of the system --- p.79 / Chapter 9.2 --- Experimental Setup of the system --- p.80 / Chapter 9.3 --- Experimental Results on lifting a mass platform --- p.81 / Chapter 10. --- 2-D PVDF-Based Sensing System --- p.90 / Chapter 10.1 --- Design of the Sensing System --- p.90 / Chapter 10.2 --- Experimental Setup --- p.91 / Chapter 10.3 --- Calibration of the 2-D Sensing System --- p.92 / Chapter 10.3.1 --- Noise Signal from the system --- p.92 / Chapter 10.4 --- Experiments Results on touching a substrate --- p.94 / Chapter 11. --- Experimental Analysis --- p.97 / Chapter 11.1 --- Data Acquisition --- p.97 / Chapter 11.2 --- Spectrum Analysis of the Experimental Data --- p.101 / Chapter 12. --- Conclusion --- p.103 / Chapter 13. --- Future Work --- p.105 / Chapter 13.1 --- Control of the Sensing System --- p.105 / Chapter 13.2 --- Tele-operation System on force feedback sensing system --- p.107 / Chapter A. --- Appendix --- p.109 / Chapter A. 1 --- Procedures in using probe station --- p.109 / Bibliography --- p.110

Optical detection devices such as optical biosensors and optical spectrometers are widely used in many applications for the functions of measurements, inspections and analysis. Due to the large dimension of prisms and gratings, the traditional optical devices normally occupy a large space with complicated components. Since cheaper and smaller optical devices are always in demand, miniaturization has been kept going for years. Thanks to recent fabrication advances, nanophotonic devices such as semiconductor laser chips have been growing in number and diversity. However, the optical biosensor chips and the optical spectrometer chips are seldom reported in the literature. For the reason of improving system integration, the study of ultra-compact, low-cost, high-performance and easy-alignment optical biosensors and optical spectrometers are imperative. This thesis is an endeavor in these two subjects and will present our research work on studying the optical transmission properties of dielectric aperture arrays and developing new optical biosensors and optical spectrometers. / Subsequently, optical transmission properties through a self-mixing interferometer array are studied and a novel high-resolution cost-effective optical spectrometer is proposed. The miniature interferometer-based spectrometer is made of polymethyl methacrylate (PMMA) with a CCD as the detector. The detected intensity of each CCD pixels contains the spectral information. Since each frequency component in the incoming beam corresponds to a unique phase difference of the two beam portions of each optical interferometer, the total intensity received by each CCD pixel, which is resulted from the addition of the interference signals from all the frequency components in the beam, should also be unique. Therefore, the spectrum calculation is a problem to solve an ill-posed linear system by using Tikhonov regularization method. Simulation results show that the resolution can reach picometer level. Apart from the choice of path difference between the interfering beams, the spectral resolution also depends on the signal-to-noise ratio and analogue-digital conversion resolution (dynamic range) of the CCD chip. In addition, the theory of uniform waveguide scattering is explored to expand the possibility of using such mini-interferometers for performing free-space spectral analysis of waveguide devices. At the same time, the method of least squares is used to correct the pixel non-uniformity of the CCD so as to improve the performance of the spectrometer. / The first half of the thesis demonstrates that the optical phase shift associated with the surface plasmon (SP) assisted extraordinary optical transmission (EOT) in nano-hole arrays fabricated in a metal film has a strong dependence on the material refractive index value in close proximity to the holes. A novel refractive index sensor based on detecting the EOT phase shift is proposed by building a model. This device readily provides a 2-D biosensor array platform for non-labeled real-time detection of a variety of organic and biological molecules in a sensor chip format, which leads to a high packing density, minimal analyte volumes, and a large number of parallel channels while facilitating high resolution imaging and supporting a large space-bandwidth product (SBP). Simulation (FDTD Solutions, Lumerical Solutions Inc) results indicate an achievable sensitivity limit of 4.37x10-9 refractive index units (RIU) and a dynamic range as large as 0.17 RIU. / The sensor chip and spectrometer chip introduced here are based on the interference of light transmitted through dielectric aperture arrays. Their compact feature renders these devices ideal for miniaturization and integration as the systems in microfluidics architectures and lab-on-chip designs. / Yang, Tao. / Adviser: H. P. Ho. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 150-163). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Ouyang, Mengxing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 83-88). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Background and Motivation --- p.1 / Chapter 1.2 --- Objectives --- p.2 / Chapter 1.3 --- Contributions --- p.3 / Chapter 1.4 --- Organization of the Dissertation --- p.3 / Chapter 2. --- CNTs and Their Application as Sensors --- p.5 / Chapter 2.1 --- Introduction to CNTs --- p.5 / Chapter 2.2 --- CNTs Based Sensors --- p.8 / Chapter 3. --- F-CNTs Based Ethanol Sensors --- p.10 / Chapter 3.1 --- Introduction --- p.10 / Chapter 3.1.1 --- Carbon Nanotube Alcohol Sensors --- p.11 / Chapter 3.1.2 --- CNTs Sensor Configuration --- p.12 / Chapter 3.1.3 --- Activation of CNTs Sensor --- p.13 / Chapter 3.1.4 --- Functionalization of CNTs --- p.14 / Chapter 3.2 --- Fabrication of F-CNTs Based Ethanol Sensors --- p.16 / Chapter 3.2.1. --- Fabrication of f-CNTs --- p.16 / Chapter 3.2.2. --- Fabrication of Sensing Elements by DEP Manipulation --- p.17 / Chapter 3.2.3. --- Experimental Setup --- p.19 / Chapter 3.2.4. --- Mechanism of Ethanol Sensor --- p.20 / Chapter 3.3 --- Characterization of F-CNTs Based Ethanol Sensors --- p.21 / Chapter 3.3.1. --- I-V Characteristics --- p.21 / Chapter 3.3.2. --- Thermal Sensitivity --- p.22 / Chapter 3.3.3. --- Stability --- p.23 / Chapter 3.3.4. --- FFT and Spectral Analysis --- p.23 / Chapter 3.4 --- Performance of F-CNTs Based Ethanol Sensors --- p.26 / Chapter 3.4.1. --- Typical Response --- p.26 / Chapter 3.4.2. --- Selectivity --- p.27 / Chapter 3.4.3. --- Towards Low Concentration --- p.28 / Chapter 3.4.4. --- Towards Realistic application --- p.29 / Chapter 3.5 --- Constant Power Configuration --- p.32 / Chapter 3.5.1. --- Constant Power Circuit for Ethanol Detection --- p.32 / Chapter 3.5.2. --- Sensor Response versus Power --- p.35 / Chapter 3.5.3. --- Responsivity --- p.37 / Chapter 3.5.4. --- Noise --- p.38 / Chapter 3.5.5. --- Sensitivity --- p.39 / Chapter 3.5.6. --- Dynamic Response --- p.41 / Chapter 3.6 --- Comparison between F-MWNTs and MWNTs --- p.43 / Chapter 3.6.1. --- I-V Characteristics --- p.43 / Chapter 3.6.2. --- Cycling Response --- p.44 / Chapter 3.6.3. --- Dynamic Response --- p.46 / Chapter 3.6.4. --- Sensor Performance under Different Power --- p.48 / Chapter 3.7 --- Summary --- p.53 / Chapter 4. --- EG-CNTs Based Flow Sensors --- p.55 / Chapter 4.1 --- Introduction to CNTs Flow Sensors --- p.55 / Chapter 4.2 --- EG-CNTs and Their Applications --- p.56 / Chapter 4.2.1 --- Intro to EG-CNTs Sensor --- p.56 / Chapter 4.2.2 --- Fabrication of EG-CNTs Sensor --- p.57 / Chapter 4.2.3 --- Experimental Characterization --- p.59 / Chapter 4.2.3.1. --- I-V Characteristics --- p.59 / Chapter 4.2.3.2. --- Thermal Sensitivity --- p.61 / Chapter 4.2.3.3. --- Humidity responsivity --- p.63 / Chapter 4.2.3.4. --- Stability --- p.65 / Chapter 4.2.3.5. --- Hysteresis --- p.66 / Chapter 4.2.4 --- Summary --- p.68 / Chapter 4.3 --- Fabrication of EG-CNTs Flow Sensor --- p.70 / Chapter 4.3.1. --- Fabrication Procedure --- p.70 / Chapter 4.3.2 --- Experimental Setup --- p.73 / Chapter 4.4 --- Characterization of EG-CNTs Flow Sensor --- p.74 / Chapter 4.4.1. --- Typical Response --- p.74 / Chapter 4.4.2. --- Power Consumption --- p.75 / Chapter 4.4.3. --- Repeatability --- p.77 / Chapter 4.4.4. --- Flow Sensitivity --- p.78 / Chapter 4.5 --- Summary --- p.79 / Chapter 5. --- Conclusion --- p.80 / Chapter 6. --- Bibliography --- p.83

Triethanolamine (TEA) is a semiconducting polymer which exhibits a resistance change when exposed to various gases. The polymer also exhibits a number of reactions with nitrogen dioxide, with the reaction products being heavily dependent on the presence or absence of water vapor. Previous studies have attempted the incorporation of a TEA-carbon nanoparticle composite as the active sensing layer in a chemresistive sensor for detection of NO₂. The incorporation of carbon nanoparticles in the polymer nanocomposite was thought to amplify the sensor's response. There are a number of chemical reactions that can occur between TEA and NO₂, with the reaction products being heavily dependent on the presence and amount of water vapor in the environment. Because of this influence, it becomes necessary to know to what degree the presence of water vapor interferes with the sensing response. In this work we show that the sensor exhibits a reversible resistance change as background humidity changes. This sensitivity to humidity changes is so large that it renders undetectable any resistance change that could be caused by the reaction of TEA with NO₂. Furthermore, we show that the presence of low levels of NO₂ do not interfere with adsorption of water vapor. The detection mechanism is based on measuring resistance changes in the TEA film due to the adsorption/desorption of water vapor. The sensing response can be described by Langmuir adsorption by using a site-based model for the polymer film resistance. Breakdown of the polymer film over time due to continuous adsorption of water vapor, as well as photodegradation of the polymer film, will be discussed. SEM images will also be presented showing growth of crystallites on the electrode walls, as well as experimental results demonstrating degradation of the sensing film during sensor operation.

High speed photodetectors are a necessary element in broad band digital and analog optical communication systems. In this thesis easily integrable planar high speed photodetectors made on undoped semi-insulating (SI) GaAs substrates are modeled and tested. The fabrication process of the detectors is fully compatible with GaAs metal-semiconductor field effect transistor (MESFET) processing technology. Interdigitated fingers are used as the contacts to achieve both high sensitivity and large bandwidth. Detectors made with both ohmic and Schottky contacts are fabricated and tested. The equivalent circuit elements of the interdigitated structure are modeled using accurate lumped element circuit models associated with the various discontinuities of the structure. The results of the model agree well with the experimental results as well as with other published results. Numerical simulation of the SI-GaAs metal-semiconductor- metal (MSM) photodetector is performed. The carriers are tracked after an ideal optical pulse is applied and the intrinsic current as a function of time is computed. Then the influence of all the external circuit elements is included and the output current across the load resistor is computed. The simulated response is compared with other published models. The electrical and optical characteristics of the detectors are measured. For ohmic contact detectors, the dark current increases linearly with bias until some critical field is reached beyond which the dark current increases nonlinearly with bias. The time response of the detectors is measured with a 10 ps pulsed laser operating at - 600 nm and also with a pulsed GaAs /AlGaAs semiconductor laser operating at 850 nm. The ohmic and Schottky contact detectors have approximately the same rise time. The fall time of the Schottky contact detector is much smaller than the fall time of ohmic contact detector. The long fall time of the ohmic detector does not depend on the spacing between contacts. This long fall time is due to the large barrier that exists near the ohmic metal/SI-GaAs cathode contact. No such barrier exists for SI-GaAs MSM photodetector. The simulated impulse response of the SI-GaAs MSM photodetector is compared with the measured impulse response. / Graduation date: 1991

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No description available.

Bibliography: leaves 188-203. / xxii, 203 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / In this thesis insect vision principles are applied to the main mechanism for motion detection. Advanced VLSI technologies are employed for designing smart micro-sensors in which the imager and processor are integrated into one monolithic device. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996

A sensor is described which utilizes the phenomenon of surface plasmon resonance to detect changes in refractive index of chemical or biochemical samples applied to a surface modified optical fiber. The sensor is constructed by polishing a short section of the lateral surface of an optical fiber to its evanescent field surrounding the fiber core. One or more thin films are applied to the polished section of the fiber to produce the sensing element. One of the films is the metal silver, which acts as the support for the surface plasmon. Under the proper conditions, TM polarized energy propagating in the fiber can be coupled to a surface plasmon electromagnetic mode on the metal film. This coupling depends on the wavelength, the nature of the fiber, the refractive index and thickness of the thin films applied to the fiber, and the refractive index of a chemical sample in contact with the modified surface. The fiber to plasmon coupling is seen as a large attenuation of the light reaching the distal terminus of the fiber. / Ph. D.

The monitoring of harmful ambient vapors is of major concern in the industrial environment. To this end, the development of systems which detect and respond in real time to specific vapors is a highly desirable goal. Surface Acoustic Wave (SAW) devices have been used for chemical analysis since 1978. While sensitive to mass changes occurring on their surfaces, they are not selective to the mass they will detect. Their use as chemical sensors requires the development of specificity for a vapor (or class of vapors) using selective chemical reagents suspended in film media that can have their permeability easily changed. This dissertation presents the development of an automated dosimeter for the detection of phosgene using SAW devices. By changing the film media from a very permeable material to a film exhibiting less permeability, the analytical range of the device using the same suspended selective chemical reagent is expanded to concentrations which the very permeable film is incapable of accurately measuring. / Ph. D.