Utilizing bulk micromachining technology, this thesis aimed to develop a flexural plate-wave(FPW) device with novel groove reflection microstructure for high-sensitivity and low insertion-loss biomedical microsystem applications. The influences of the amount and depth of the groove and the distance between the groove and the boundary of ZnO piezoelectric thin-film (DGB) on the reduction of insertion-loss and the enhancement of quality factor (Q) and electromechanical coupling coefficient (K2) were investigated. Three critical technology modules established in this thesis are including the development of (1) a sputtering deposition process of high C-axis (002) orientation ZnO piezoelectric thin-film, (2) an electrochemical etch-stop technique of silicon anisotropic etching and (3) an integration process of FPW device. Firstly, under the optimized conditions of the sputtering deposition process (300¢J substrate temperature, 200 W radio-frequency (RF) power and 30/70 Ar/O2 gas flow ratio), a high C-axis (002) orientated ZnO piezoelectric thin-film with a high X-ray diffraction (XRD) intensity (50,799 a.u.) and narrow full width at half maximum (FWHM = 0.383¢X) can be demonstrated. The peak of XRD intensity of the standard ZnO film occurs at diffraction angle 2£c = 34.422¢X, which matches well with our results (2£c = 34.357¢X). Secondary, an electrochemical etch-stop system with three electrode configuration has been established in this research and the etching accuracy can be controlled to less than 1%. Thirdly, this thesis has successfully integrated the main fabrication processes for developing the FPW device which are including six thin-film deposition processes and six photolithography processes. The implemented FPW device with RIE etched groove reflection microstructure presents a low insertion-loss of -12.646 dB, center frequency of 114.7 MHz, Q factor of 12.76 and K2 value of 0.1876%.

This thesis proposes a dB-linear programmable variable gain amplifier (VGA) and a voltage peak detector with digital calibration for FPW-based antibody sensing system. In the first topic, a dB-linear programmable variable gain amplifier is proposed. By using two source followers as the input terminals, input signals with very low DC offset could be received. The linear local-feedback transconductors are employed to be trans-condurctor-stage and load-stage. Besides, a reconfiguration method is used to reduce the layout area and improve the linearity of the gain to attain gain error less than 0.86 dB measured on silicon. In the second topic, a voltage peak detector with digital calibration is proposed. The voltage peak of the input sine-wave signal is sampled and held by using an integra-tor, a digital-to-analog converter, and a voltage comparator to generate a square-wave signal. Besides, the voltage error caused by the propagation delay could be calibrated by the proposed digital calibration method. The frequency of input signal is up to 20 MHz and the voltage error is justified to be less than 0.81 % by simulations.

Abstract Compared with the other micro acoustic wave devices, the flexural plate-wave (FPW) device is more suitable for being used in liquid-sensing applications due to its higher mass sensitivity, lower phase velocity and lower operation frequency. However, conventional FPW devices usually present a high insertion loss and low fabrication yield. To reduce the insertion loss and enhance the fabrication yield of FPW device, a 1.5 £gm-thick silicon-trench reflective grating structure (RGS), a high electromechanical coupling coefficient ZnO thin-film and a 5 £gm-thick silicon oxide membrane substrate are adopted in this research. The influences of the amount of silicon trench and the distance between inter-digital transducer (IDT) and RGS on the insertion loss and quality factor of FPW device are investigated. The main fabrication technology adopted in the study is bulk micromachining technology and the main fabrication steps include six thin-film deposition and five photolithography processes. Under the optimized conditions of the sputtering deposition processes (200¢J substrate temperature, 200 W radio-frequency power and 75% gas flow ratio), a high C-axis (002) orientation ZnO piezoelectric thin-film with 31.33% electromechanical coupling coefficient can be demonstrated. The peak of XRD intensity of the standard ZnO film occurs at diffraction angle 2£c = 34.422¢X, which matches well with our results (2£c = 34.282¢X). By controlling the thickness of ZnO/Au/Cr/SiO2/Si3N4 sensing membrane less than 6.5 £gm-thick, the fabrication yield of FPW device can be improved and a low operation frequency (6.286 MHz) and high mass sensitivity (-113.63 cm2 / g) can be achieved. In addition, as the implemented FPW device with four silicon trenches RGS and 37.5 £gm distance between IDT and RGS, a low insertion loss (-40.854 dB) and very high quality factor (Q=206) can be obtained. Keywords¡Gflexural plate-wave; silicon-trench reflective grating structure; electromechanical coupling coefficient; ZnO; bulk micromachining technology

The conventional flexural plate-wave (FPW) device has advantages of high mass sensitivity, low phase velocity and low operation frequency. However, conventional FPW devices usually present a high insertion loss and low fabrication yield. This thesis aimed to reduce the insertion loss of conventional FPW devices. The influences of geometry of inter-digital transducers (IDTs), pair number of IDTs, depth of focus and length of delay line on the insertion loss of FPW device are investigated. This research utilizes bulk micromachining technique to develop a low insertion-loss FPW device and the main fabrication steps include seven thin-film deposition and four photolithography processes. As the wavelength is 100 £gm, pair number of IDTs is 20, depth of focus is 1000 £gm and length of delay line is 500 £gm, the measured insertion loss of the implemented FPW device with conventional parallel-type IDTs and novel focus-type IDTs are equal to -48 dB and -45.06 dB, respectively. On the other hand, the insertion loss of FPW device with focus-type 25-pairs IDTs (-43.69 dB) is smaller than that of FPW device with focus-type 20-pairs IDTs (-45.06 dB). Additional, the measured insertion loss of FPW device with 500 £gm focus depth (-41.47 dB) is smaller than that of FPW devices with 1000 £gm focus depth (-43.69 dB) or with 1500 £gm focus depth (-45.39 dB). Furthermore, the FPW device with 500 £gm delay line presents a smaller insertion loss (-40.46 dB) than that of FPW devices with 250 £gm delay line (-41.47 dB) or with 750 £gm delay line (-40.95 dB). Finally, under the optimized specifications (focus-type/25 pairs IDTs, 500 £gm focus depth and 500 £gm delay line), the FPW-based microsensor demonstrates a high sensitivity (91.53 cm2/g), high sensing linearity (99.18 %) and low insertion loss (-40.46 dB), hence it is very suitable for development of biomedical sensing microsystem.

Utilizing self-assembled monolayer nanotechnology, micro-electro-mechanical systems (MEMS) and IC technologies, a novel flexural plate-wave (FPW) biosensor is developed in this dissertation for detecting the immunoglobulin-E (IgE) concentration of human serum. The acoustic waves of the proposed FPW devices are launched by the 25-pair inter-digital transducer (IDT) input electrodes and propagated through the 4.82 £gm-thick Si/SiO2/Si3N4/Cr/Au/ZnO floating thin-plate. Since the thickness of such floating thin-plate is much smaller than the designed wavelength of FPW device (80 £gm), most of the propagating wave energy will not be dissipated into outside of thin-plate and the mass sensitivity is very high. To further reduce the insertion loss of the proposed FPW devices, two 3 £gm-thick Al reflection grating electrodes (RGE) are designed beside the input and output IDTs. To implement a FPW-based IgE biosensor, a Cr/Au electrode layer has to be deposited on the backside of the floating thin-plate to serve as a substrate for further coating the cystamine SAM/glutaraldehyde/IgE antibody layers. Once the IgE antigens of human serum are bound to the IgE antibody layer, the small change in the mass of floating thin-plate will result in a shift of center frequency of the testing FPW-based biosensor. Compared to the reference FPW biosensors, the shift of center frequency generated by the testing FPW biosensor under different IgE antigen concentration can be detected by commercial network analyzer or the frequency-shift readout system developed by our collaboration laboratory (VLSI Design Lab. of NSYSU). Compared to commercial enzyme linked immunosorbent assay (ELISA) analyzer (sample volume >25 £gl/well, testing time >60 min, dimension>40 cm ¡Ñ30 cm¡Ñ10 cm), the implemented FPW-based IgE biosensor presents a smaller sample volume (<5 £gl), faster response (<10 min) and smaller size (<9 mm¡Ñ6 mm¡Ñ0.5 mm). In addition, a very low insertion loss (-9.2 dB), a very high mass sensitivity (-6.08¡Ñ109 cm2 g-1) and a very high sensing linearity (99.46 %) of the proposed IgE biosensor can be demonstrated at 6.6 MHz center frequency. This study successfully developed a novel FPW-based allergy biosensor by MEMS technology, which has great potential to be further applied into point-of-care testing (POCT) microsystem.

The conventional medical immunoassays (ELISA/CLIA/FPIA) are not only costly (>10,000 USD), large in size (>10,000 cm3), but also require a vast number of sampling (25 £gL/well ¡Ñ 12 well) and long detection time (1~2.5 hr). To develop a biomedical microsensor for the application of portable detecting microsystem, this thesis proposes a flexural plate wave (FPW) microsensor with a novel reflection grating electrode (RGE) microstructure. Comparing to the conventional acoustic microsensors, the FPW based device has higher mass sensitivity, lower operation frequency but higher noise level. To overcome this disadvantages, this study added the RGE microstructure into the design of FPW sensor and investigated its influences on the reduction of insertion loss and noise level. By using the surface and bulk micromachining technologies, this thesis designed and fabricated FPW-based mass-sensing device with a small volume of 0.189 cm3 and a novel RGE microstructure. The main processing steps adopted in this research include six photolithoghaphies and nine thin-film depositions. In this work, a high figure-of-merit C-axial orientation ZnO piezoelectric thin-film was deposited by a commercial magnetic radio-frequency (RF) sputter system. On the other hand, the gold/chrome interdigital transducer (IDT) and RGE aluminum electrode were deposited utilizing a commercial E-beam evaporator system. For the optimization of design specifications of the FPW devices, the space of input and output IDTs, pair number of IDT, length of delay line gap and with/without RGE design were varied and investigated. Under the optimized IDT specification, the FPW microstructure presents lower central frequency (2¡ã4 MHz), insertion loss (-11 dB) and noise level (<-30 dB) than that of the FPW based microsensor without RGE microstructure. In addition, as the sampling volume of the testing DI water is equal to 1 £gL, a high mass sensitivity (-48.3 cm2/g) and short responding time (5 min) of the FPW microsensor with RGE design can be achieved in this work. The excellent characteristics mentioned above demonstrated the implemented FPW microsensor is very suitable for the applications of portable biomedical detecting microsystems.

An innovative strengthening technique is applied for the first time in this study to provide flexural strengthening in two-way reinforced concrete (RC) slabs supported on edge beams. The technique comprises external bonding of textiles on the tension face of RC slabs through the use of polymer-modified cement- based mortars. The textiles used in the experimental campaign comprised fabric meshes made of long stitch-bonded fibre rovings in two orthogonal directions. The specimens measured 2 x 2 m in plan and were supported on hinges at the corners. Three RC slabs strengthened by textile reinforced mortar (TRM) overlays and one control specimen were tested to failure. One specimen received one layer of carbon fibre textile, another one received two, whereas the third specimen was strengthened with three layers of glass fibre textile having the same axial rigidity (in both directions) with the single-layered carbon fibre textile. All specimens failed due to flexural punching. The load-carrying capacity of the strengthened slabs was increased by 26%, 53%, and 20% over that of the control specimen for slabs with one (carbon), two (carbon) and three (glass) textile layers, respectively. The strengthened slabs showed an increase in stiffness and energy absorption. The experimental results are compared with theoretical predictions based on existing models specifically developed for two-way slabs and the performance of the latter is evaluated. Based on the findings of this work the authors conclude that TRM overlays comprise a very promising solution for the strengthening of two-way RC slabs.

The Llanos foreland basin of Colombia is located along the eastern margin of the northern Andes. The Llanos basin is bounded to the north by the Mérida Andes, to the east by the Guiana shield, to the south by the Serrania de la Macarena, and to the west by the frontal foothills thrust system of the Andes (the Cordillera Oriental). The Llanos foreland basin originated in the Maastrichtian, after a post-rift period during the Mesozoic, and recorded an abrupt pulse of middle Miocene subsidence possibly in response to subduction and collision events along the Pacific margin of northwestern South America. Regional east-west shortening, driven in part by collision of the Panama arc along the Pacific margin of Colombia, has built the widest part of the northern Andes. This wide area (~600 km) includes a prominent arcuate thrust salient, the Cordillera Oriental, which overthrusts the Llanos foreland along a broad V-shaped salient that projects 40 km over the northern Llanos foreland basin. In this study, I interpret 1200 km of 2D seismic data tied to 18 wells and regional potential fields (gravity and magnetic) data. Interpreted seismic data are organized into four regional (300 to 400-km-long) transects spanning the thrust salient area of the northern Llanos basin. I performed 2D flexural modeling on the four transects in order to understand the relative contributions of flexural subsidence due to tectonic and sedimentary loading. Sedimentary backstripping was applied to the observed structure maps of six Eocene to Pleistocene interpreted horizons in the foreland basin in order to remove the effects of sedimentary and water loading. Regional subsidence curves show an increase in the rate of tectonic subsidence in the thrust salient sector of the foreland basin during the middle to late Miocene. The flexural models predict changes in the middle Miocene to recent position of the eastern limit of foreland basin sediments as well as the changing location and vertical relief of the flexurally controlled forebulge. Production areas of light oil in the thrust belt and foreland basin are located either south of the thrust salient (Cusiana, Castilla, Rubiales oilfields) or north of the salient (Guafita-Caño Limon, Arauca oilfields) but not directly adjacent to the salient apex where subsidence, source rock thicknesses, and fracturing were predicted by a previous study to be most favorable for hydrocarbons. There are no reported light oil accumulations focused on the predicted present or past positions of the forebulge, but detailed comparisons of seismic reflection data with model predictions may reveal stratigraphic onlap and/or wedging relationships that could provide possible traps for hydrocarbons. / text

Self consolidating concrete (SCC) is widely used in the construction industry. SCC is a high performance concrete with high workability and consistency allowing it to flow under its own weight without vibration and making the construction of heavily congested structural elements and narrow sections easier. Fiber reinforced polymer (FRP) reinforcement, with its excellent mechanical properties and non-corrosive characteristic, is being used as a replacement for conventional steel reinforcement. In spite of the wide spread of SCC applications, bond and flexural behaviour of SCC beams reinforced or prestressed with FRP bars has not been fully studied. Furthermore, the ACI 440.1R-06 equation for determining the development length of FRP bars is based on Glass FRP (GFRP) bars and may not be applicable for Carbon FRP (CFRP) bars. This research program included an experimental and analytical study to investigate the flexural and bond behaviour of SCC beams reinforced with FRP bars and SCC beams prestressed with CFRP bars. In the experimental phase, fifty-six beams were fabricated and tested. Sixteen of these beams were prestressed with CFRP bars and forty beams were reinforced with non-prestressed GFRP or CFRP bars. Four concrete batches were used to fabricate all the specimens. Three mixes were of self consolidating concrete (SCC) and one mix was of normal vibrated concrete (NVC). The test parameters for the non-prestressed beams were the concrete type, bar type and bar diameter, concrete cover thickness and embedment length while the test parameters for the prestressed beams were the concrete type and the prestressing level (30%, 45% and 60%). The transfer length of the prestressed CFRP bars was determined by means of longitudinal concrete strain profile and draw-in methods. All beams were tested in four-point bending to failure. Measurements of load, midspan deflection, bar slip if any at the beam ends, strain in reinforcing FRP bar at various locations, and strain in concrete at the beam midspan were collected during the flexural test. The concrete compressive strength at flexural tests of SCC mix-1, mix-2, and mix-3 were 62.1MPa, 49.6MPa and 70.9MPa, respectively and for the NVC mix was 64.5MPa. The material test results showed that SCC mixes had lower modulus of elasticity mechanical properties than the NVC mix. The modulus of elasticity of the SCC mixes ranged between 65% and 82% of the NVC mix. The modulus of rupture of the SCC mixes was 86% of the NVC mixes. The test results for beams prestressed with CFRP bars revealed that the variation of transfer length of CFRP bars in SCC versus their prestressing level was nonlinear. The average measured transfer lengths of 12.7mm diameter CFRP bars prestressed to 30%, 45% and 60% was found to be 25db, 40db, 54db, respectively. Measured transfer lengths of the 12.7mm diameter CFRP bar prestressed to 30% in SCC met the ACI440.4 prediction. However, as the prestressing level increased, the predicted transfer length became unconservative. At a 60% prestress level, the measured/prediction ratio was 1.25. Beams prestressed with CFRP bars and subjected to flexural testing with shear spans less than the minimum development length had local bar slippage within the transmission zone. Beams that experienced local bond slip, their stiffness was significantly decreased. A modification to the existing model used to calculate the transfer and development lengths of CFRP bars in NVC beams was proposed to account for the SCC. The test results for beams reinforced with FRP bars indicated that the average bond strength of CFRP bars in NVC concrete is about 15% higher than that of GFRP bars in NVC. The ACI 440.1R-06 equation overestimated the development length of the CFRP bars by about 40%, while CAN/CSA-S6-06 equation was unconservative by about 50%. A new factor of (1/1.35) was proposed to estimate the development length of the CFRP bars in NVC when the ACI440.1R-06 equation is used. Beams made from SCC showed closer flexural crack spacing than similar beams made from NVC at a similar loading. The deflection of beams made from SCC and reinforced with CFRP bars was found to be slightly larger than those made from NVC. The average bond stresses of GFRP and CFRP bars in SCC were comparable to those in NVC. However, FRP bars embedded in SCC beams had higher bond stresses within the uncracked region of the beams than those embedded in NVC beams. In contrast, FRP bars in SCC had lower bond stresses than FRP bars in NVC within the cracked region. The average bond strength of GFRP in SCC was increased by 15% when the concrete cover thickness increased from 1.0db to 3.0db. Cover thicknesses of 2db and 3db were found to be sufficient to prevent bond splitting failure of GFRP and CFRP bars in SCC, respectively. Bond splitting failure was recorded when the cover thickness dropped to 1.5db for the GRP bars and to 2.0db for the CFRP bars. An insignificant increase in average bond stress was found when the bar diameter decreased from 12.7mm to 6.3mm for the CFRP bars, and a similar increase occurred in GFRP bars when the bar diameter decreased from 15.9mm to 9.5mm. New models to calculate the development length of GFRP and CFRP bars embedded in SCC were proposed based on the experimental results. These models capture the average bond stress profile along the embedment length. A good agreement was found between the proposed model and the experimental results. Analytical modeling of the load-deflection response based on the effective moment of inertia (ISIS Canada M5) was unconservative for SCC beams reinforced with CFRP bars by 25% at ultimate loading. A new model for bond stress versus Ma/Mcr (applied moment to cracking moment) ratio was developed for GFRP and CFRP bars in SCC and for CFRP bars in NVC. These bond stress models were incorporated in a new rigorous model to predict the load-deflection response based on the curvature approach. The FRP bar extension and bond stress models were used to calculate the load-deflection response. With these models 90% of the calculated deflections were found to be within ± 15% of the experimental measured results for SCC beams reinforced with FRP bars. Analytical modeling of the load-deflection for NVC and SCC beams prestressed with CFRP bars are proposed done. The moment resistance was calculated using Sectional Analysis approach. The deflection was calculated using simplified and detailed methods. The simplified method was based on the effective moment of inertia while the detailed method was based on effective moment of inertia and effective centroid. The experimental results correlated well with the detailed method at higher loads range. This study provided an understanding of the mechanism of bond and flexural behaviour of FRP reinforced and prestressed SCC beams. The information presented in this thesis is valuable for designers using FRP bars as flexural reinforcement and also for the development of design guidelines for SCC structures.

Epoxy resin is an important engineering material in many industries such as electronics, automotive, aerospace, etc not only because it is an excellent adhesive but also because the materials based on it provide outstanding mechanical, thermal, and electrical properties. Epoxy resin has been proved to be an excellent matrix material for the nanocomposites when including another phase such as inorganic nanofillers. The properties of a nanocomposite material, in general, are a hybrid between the properties of matrix material and the nanofillers. In this sense, the thermal, mechanical, and electrical properties of a nanocomposite may be affected by the corresponding properties of matrix material. When the sonication is used to disperse the nanofillers in the polymer matrix, with the dispersal of the nanofillers, there comes some modification in the matrix as well and it finally affects the properties of nanocomposites. In this regard, we attempted to study the thermal, mechanical, and dynamic properties of EPON 862 epoxy resin where ultrasonic processing was taken as the effect causing variable. Uncured epoxy was subjected to thermal behavior studies before and after ultrasonic treatment and the cured epoxies with amine hardener EPICURE 3223 (diethylenetriamine) after sonications were tested for mechanical and dynamic properties. We monitored the ultrasonic processing effect in fictive temperature, enthalpy, and specific heat capacity using differential scanning calorimetry. Fictive temperature decreased whereas enthalpy and specific heat capacity were found to increase with the increased ultrasonic processing time. Cured epoxy rectangular solid strips were used to study the mechanical and dynamic properties. Flexural strength at 3% strain value measured with Dillon universal testing machine under 3-point bending method was found to degrade with the ultrasonic processing. The storage modulus and damping properties were studied for the two samples sonicated for 60 minutes and 120 minutes. Our study showed that the 60 minutes sonicated sample has higher damping or loss modulus than 120 minutes sonicated sample.