The interest in tiny wireless applications raises the demand for an integrated reference oscillator with the same performance as the macroscopic quartz crystal reference oscillators. The main challenge of the thesis is to prove that it is possible to build a MEMS based oscillator that approaches the accuracy level of existing quartz crystal oscillators. The MEMS resonator samples which Philips provides are measured and an equivalent electrical model is designed for them. This model is used in the simulations of the Pierce oscillator and the transresistance amplifier oscillator that are evaluated in this thesis. Finally the Pierce oscillator is implemented in the A BCD2 process and manufactured at Philips Semiconductors in Nijmegen, The Netherlands. A test board, for measuring the Pierce oscillator together with a MEMS resonator or a quartz crystal resonator, is built. The Pierce oscillator is then measured with a quartz crystal resonator. In order to simulate the higher series resistance of the MEMS resonators a resistor is put in series with the quartz crystal. The Pierce oscillator is working with a series resistance of 1 kΩ. With higher series resistance the Pierce oscillator stops working. In circuit simulations the Pierce oscillator is working with a series resistance of about 5 kΩ in the MEMS resonator model. To be sure whether the Pierce oscillator has enough gain for the MEMS resonators, it needs to be measured with them. Temperature variations in the MEMS resonators need to be handled and the phase noise performance of the oscillator must be improved, in order for the MEMS based reference oscillator to be a successful replacement for the quartz crystal reference oscillator.

This thesis aimed to design and develop a novel micro-thermal electric generator (£g-TEG) with a transparent parallel-array bridge microstructure using the ANSYS finite element analysis software and Micro Electro Mechanical Systems (MEMS) technology. The presented £g-TEG can convert the temperature difference between the indoor and outdoor planes of building glass window into a useful electrical power. The thermoelectrically transferred output electrical power is suitable for recharging various mobile communication products. Conventional £g-TEG presented a high fabrication cost, low integration compatibility with IC processes and non-transparent characteristics. To improve these disadvantages, this research utilizes a batch production surface micromachining technology to implement the Poly-Si based parallel-array £g-TEG on a transparent quartz glass substrate and the main fabrication processes adopted in this research are including six thin-film deposition processes and five photolithography processes. The implemented Poly-Si based transparent £g-TEG has successfully demonstrates a maximum temperature difference of 1.38¢J between the hot plane (substrate) and cold plane (suspending microstructure), a maximum output voltage of 13.28 mV/cm2, a maximum output power of 110.22 nW/cm2 and a maximum light transmission of 40%.

Oriented needle-shaped or rod-shaped quartz precipitates occur in clinopyroxenes have been commonly observed in eclogites or garnet peridotites from the high pressure or ultra-high pressure (HP/UHP) metamorphic belts, and their occurrence has been used as an indicator of UHP metamorphism. However, the origin of those quartz precipitates and their crystallographic orientation relationships with clinopyroxene hosts are still not clear. In order to understand the formation mechanisms and environments of the quartz precipitates, the present study has used electron backscattered diffraction (EBSD) analysis, petrographic and scanning electron microscopy, and electron microprobe analysis to study textural features, mineral assemblages, mineral compositions, and crystallographic orientation relationships of mineral precipitates in the omphacite from Xitieshan, North Qaidam UHP metamorphic belt. The results show that the oriented rod-like precipitates in the omphacite hosts are mainly composed of quartz + edenite, and the rods are 5~20

Veins are ubiquitous features in deformed rocks. Despite observations on syntectonic veins spanning two centuries, fundamental questions remain unanswered. Their origin as fractures is largely established but it is still not known why these fractures initiate where they do and how the vein evolves once started. We studied veins from the Lower Ordovician Mazarn Formation in the Arkansas’ Ouachitas combining textural observations, stable isotopes, fluid inclusions, SEM-based cathodoluminescence and electron back-scattered diffraction to understand the initial stage of vein formation, its later evolution, the role of fluids and their environment of formation. The veins are located at boudin necks and are synchronous with cleavage formation. Texturally, veins are characterized by veinlets (thin veins between 5 and 25 μm thick) that parallel the vein-host interface and fibers (columns of quartz or calcite) perpendicular to the vein-host interface between 30 and 350 μm wide. Veinlets are localized fractures filled with quartz. The crystallographic orientation of the precipitated material in veinlets is inherited from host grains at the micron scale and replicated as fibers’ lengths grow to centimeters. The vein-forming fluid was cyclically supersaturated yet never very far from saturation. δ18O values of vein quartz and host are within 2‰ of each other suggesting that the fluid was rock-buffered. Nevertheless, δ18O and δ13C define a ‘J’ shaped trend. Although it is not possible to date any portion of this curve, the simplest explanation is that the fluid evolved from rock-buffered in a closed system to fluid-dominated in an open system. The range of pressure-temperature conditions of vein formation is between 275 and 385 °C and 1100 and 3400 bars, from fluid inclusions and quartz-calcite oxygen isotopes thermometry. By examining a vein from tip to middle, we have established a sequence of events from inception to maturity in vein growth. Vein formation starts with folding followed by flattening of resistant sandstone layers which in turn gives rise to boudinage. Boudinage formation allowed for fracture localization along boudin-necks. The vein grew by the repeated addition of veinlets in the neck region. Recrystallization later modified the fibers by obliterating some evidence of the veinlets and moving fiber walls.

The temperature coefficient of frequency (TCF), electromechanical coupling coefficient (K2) and surface acoustic wave (SAW) velocity are the major factors when choosing the substrates for surface acoustic wave devices. There exist a wide range for the designer to controll the above factors. This thesis adopted several methods to change the properties of SAW devices. First, the SAW velocity is increased using aluminum nitride (AlN) thin films deposited on z-cut LiNbO3 substrates. Besides, the ST-quartz is adopted as substrate for comparison to clarify the temperature characteristic of AlN itself. The well-known positive TCF material, silicon dioxide (SiO2), is also deposited on z-cut LiNbO3 substrates for the purpose of improving the TCF of SAW devices. Finally, the optimal piezoelectric bilayer structures will be conducted for the improvement of the properties of SAW devices on LiNbO3 substrate. AlN and SiO2 thin films are selected to be deposited on z-cut LiNbO3 and ST-cut quartz substrates using the reactive RF magnetron sputtering. The characteristics of AlN thin films are evaluated using the analyses of XRD, SEM and AFM. The optimized growth parameters of highly c-axis oriented AlN films deposited on LiNbO3 substrate are sputtering pressure of 3.5 mTorr, nitrogen concentration (N2/N2+Ar) of 60%, RF power density of 8.1 W/cm2 and substrate temperature of 400¢J. On the other hand, the optimal parameters for highly c-axis oriented AlN films deposited on quartz substrate are sputtering pressure of 15 mTorr, nitrogen concentration of 30%, RF power density of 8.1 W/cm2 and substrate temperature of 400¢J. In addition, the interdigital transducers (IDTs) are fabricated on LiNbO3, AlN/LiNbO3, SiO2/LiNbO3, quartz and AlN/quartz substrates, respectively. The characteristic parameters of SAW devices are measured by Hewlett-Packard (HP) 8720 network analyzer. For SiO2/LiNbO3 SAW devices, the SiO2 thin films reveal the compensation of TCF, but the surface wave velocity remain almost unchanged. For AlN/quartz SAW devices, the positive temperature coefficient of AlN is clarfied by taking ST-quartz substrates as comparison. For AlN/LiNbO3 SAW devices, the characteristic improvements of frequency increase and TCF compensation of LiNbO3 SAW devices are achieved at the same time.

Time Resolved OSL (TR-OSL) is a technique to record the luminescence decay curve data after a brief stimulation pulse and can possibly be used for the separation of luminescence signals from quartz and feldspars. In this study luminescence emission from quartz and feldspar samples was investigated. TR-OSL signals of these samples were studied for the variations with preheating and annealing temperature, stimulation pulse width and total stimulation time, optical bleaching, radiation dose and measurement temperature. TR-OSL decay lifetime of quartz samples was found as ~40 &micro / s. Na-feldspar and K-feldspar luminescence signals were deconvoluted using a linear sum of three exponential decays with lifetimes about 45 &micro / s, 8 &micro / s and 1 &micro / s and about 35 &micro / s, 7 &micro / s and 0.6 &micro / s, respectively. Since feldspars signals have a component with lifetime similar to that of quartz (~40 &micro / s), luminescence signal separation with TR-OSL seems to be not straightforward.

Mineral treatment processes generally produce wastewaters containing ultrafine and colloidal particles that cause pollution upon their discharge into environment. It is essential that they should be removed from the wastewater before discharge. This study was undertaken by using synthetic turbid systems containing kaolinite and quartz particles in water with the amount of 0.20 g/L and 0.32 g/L, respectively. Removal of the turbidity was tried in two ways / electrocoagulation with aluminum anode and conventional coagulation with aluminum sulfate. Several key parameters affecting the efficiency of electrocoagulation and coagulation were investigated with laboratory scale experiments in search of optimal parameter values. Optimal values of the parameters were determined on the basis of the efficiency of turbidity removal from ultrafine suspensions. The parameters investigated in the study were suspension pH, electrical potential, current density, electrocoagulation time, and aluminum dosage. This study was also performed to compare electrocoagulation and conventional coagulation regarding the pH ranges under investigation and coagulant dosages applied. A comparison between electrocoagulation and coagulation was made on the basis of total dissolved aluminum, revealing that electrocoagulation and coagulation were equally effective at the same aluminum dosage for the removal of ultrafine particles from suspensions. Coagulation was more effective in a wider pH range (pH 5-8) than electrocoagulation, which yielded optimum effectiveness in a relatively narrower pH range around 9. In both methods, these pH values corresponded to near-zero zeta potentials of coagulated kaolinite and quartz particles. The mechanism for both coagulation methods was aggregation through charge neutralization and/or enmeshment in aluminum hydroxide precipitates. Furthermore, the experimental results confirmed that electrocoagulation could display some pH buffering capacity. The kinetics of electrocoagulation was very fast (&lt / 10 min) in approaching a residual turbidity, which could be modeled with a second-order rate equation.

Albite (Na-feldspar) and orthoclase (K-feldspar) are the major feldspar minerals used in the production of glass and ceramics. They are found together with impurities like biotite, muscovite, quartz and rutile which are not desired for ceramics and glass industries. Therefore, these have to be removed to make the ore available for industrial use. In order to shed light on the actual feldspar ores, in this study / the flotation characteristics of albite, biotite, muscovite, orthoclase, quartz and rutile were investigated separately in their pure forms. In the investigation, the electrokinetic potential measurements and micro-flotation studies have been carried out to get information about their flotation characteristics under the effect of three different collectors, Aero 704, Aero 3000C and Aero 825, and the pH of the medium. The flotation recoveries were found to be pH dependent and the effective between the pH range of 7.0 and 11.5 in the presence of Aero 704. In the case of flotation with Aero 3000C, the recoveries reached up to 95.0% at certain concentrations and pH values and decreased sharply below pH 3.0 and above pH 9.5 for all the minerals tested. In the presence of Aero 825, the flotation recoveries of the minerals except for rutile, were found to be insufficient even with its highest concentration. In order to evaluate the adsorption mechanism of the collectors, Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR) analyses were carried out. From the AFM results it might be deduced that the behavior of Aero 3000C and Aero 825 was found to be almost similar for biotite and muscovite as monolayer adsorption and for the remaining minerals, albite, orthoclase, quartz and rutile, as monolayer and bilayer adsorption together. In the case of Aero 704, for albite and orthoclase, the adsorption of the collector might be the reason for monolayer and bilayer formation on their surfaces. The strength of the interaction of the collectors on the mineral surfaces was followed by FTIR analyses before and after acetone washing. The interaction of all the collectors was found to be weak in the case of albite, orthoclase, quartz and rutile whereas the interaction of Aero 704 and Aero 3000C was found to be strong in the case of biotite and muscovite.

The distinct response of biological systems to the two enantiomers of a chiral chemical has led to a large market for enantiopure pharmaceuticals and raised fundamental issues about the origin of biological homochirality. It is therefore important to understand the interactions of chiral molecules with chiral environments. Chiral environments associated with solid surfaces could potentially play a useful role in chirally specific chemical processing. There are a variety of routes for creating chiral solid surfaces. Surfaces of materials whose bulk crystal structure is enantiomorphic can be used as one type of chiral solid surfaces. Metal surfaces that are intrinsically chiral due to the presence of kinked surface steps provide another route for creating chiral solid surfaces. Alternatively, we can impart chirality onto surfaces by attaching irreversibly adsorbing chiral organic species on otherwise achiral surfaces. Understanding and ultimately controlling enantiospecific interactions of molecules on this kind of surfaces requires detailed insight into the adsorption geometries and energies of these complex interfaces. To tackle these issues, we performed density functional theory (DFT) calculations that have proved to be a useful tool for quantitative prediction of these effects. Besides our main topic above, we theoretically examine the effects of K atoms as a promoter coadsorbed with small molecules on Mo2C surfaces, a promising catalyst for a range of chemicals applications. Our results in this thesis provide fundamental information about these systems and demonstrate that using DFT for this purpose can be a useful means of identifying the phenomena that control chiral surface chemistry.

The primary objective of this study was to develop a sensitive and cost-effective sorption system to analyze adsorption and diffusion of different gases on micro porous materials and nanotubes. A high pressure Quartz Crystal Microbalance (QCM) based adsorption apparatus for single-component gas was developed. A QCM is an acoustic-wave resonator in which the acoustic wave propagates through the crystal. Therefore, it is highly responsive to addition or removal of small amounts of mass adsorbed or deposited on the surface of the crystal. This mass sensitivity makes the QCM an ideal tool for the study of gas adsorption. The QCM-based adsorption apparatus is advantageous over the commercialized none-gravimetric and gravimetric equipment in a way that it is low-cost, highly sensitive and accurate for mass sorption applications, satisfactorily stable in a controlled environment, and can be used for thin films. The high pressure apparatus was calibrated using Matrimid 5218, whose thermodynamic properties and adsorption parameters are known. The Matrimid was spin-coated onto a 14 mm-diameter QCM, and sorption equilibrium data for were obtained for CO₂ gas at 25, 30, 48, and 52 ºC and partial pressure range between 0 to 4 bar. In order to compare the experimental data with available literature data, the experimental data was fitted into a dual-mode adsorption model. The model results from Henry's law and a Langmuir mechanism. Comparison of the experimental adsorption isotherm of Matrimide for CO₂ gas with literature data showed reasonable agreement between the experimental and literature data. In this study, the adsorption parameters of aluminosilicate nanotubes are observed. Aluminosilicate nanotubes are ideal materials for chemical sensing, molecule separation, and gas storage; hence, there is a need for adsorption and diffusion data on this material. The adsorption of CO₂, N₂, and CH₄ gases on aluminosilicate nanotubes samples has been studied in the temperature range of 20° to 120° Celsius and pressure range of 0 to 8 bar. The experimental results yield the CO₂ and N₂ heat of adsorptions of -32.9 and -28.1 kJ/mol respectively.