Experimental constraints on fluid-rock reactions during incipient serpentinization of harzburgite
Klein, Frieder
2014-10-20
Search results
24 records were found.
It is the focus of this project to explore the possibility of achieving Radio Fre¬quency (RF) micro-devices on flexible polymer substrates. To this end standard MEMS fabrication methods have been tailored to allow the integration of func¬tional materials and device patterning for production of RF MEMS devices with flexible organic substrates. Material quality, device yield, performance and re-liability are critical aspects of our study.
The project encompasses the use of a direct integration method for the creation of Film Bulk Acoustic Resonators (FBARs) on Liquid Crystal Polymer (LCP) substrates. An FBAR is a passive component used for resonance and filtering purposes. Its production on organic substrates would lead to a number of ad-vantages including: overall cost savings, size reduction and ability of the device to be directly int...
This work focuses on the development of a method for probing the mechani-
cal response of thin film materials based on miniature tensile testing. A number
of mechanisms that may compromise the performance and potentially limit the
operational lifetime of MEMS devices which incorporate functional ferroelectric
ceramics were also identified and investigated. Reliability of piezo MEMS com-
ponents was studied at a wafer and at a device level through the development
of appropriate techniques based on miniature tensile testing, time- resolved mi-
cro RAMAN spectroscopy and laser Doppler vibrometry. Micro tensile testing
was further used for the extraction of the elastic properties of various thin film
materials.
A miniature tensile stage was developed in common with DEBEN UK for
the mechanical characterization of functional thin film materi...
Optimisation can be viewed in many ways including that which is new and
improvements to the materials, or methods that are already in place. Therefore we can
define the two specific areas that make up the investigation relating to this work; those
pertaining to new materials which may improve performance, and an analysis of the
methods, and results, with regard to adhesion of the dissimilar materials incumbent in
the present structures.
In this work, two candidate materials have been identified in order to improve the
performance of the electrode structures present in MEMS devices used for piezoelectric
applications. These are the conductive oxides, Lanthanum Nickel Oxide and Ruthenium
Oxide, which have shown considerable promise because of their reported improvements
in fatigue properties with PZT applications. They have been investig...
This thesis focuses on the use of high permittivity tunable dielectrics and more
specifically sol-gel ferroelectric thin films for low cost, high performance tunable
devices such as varactors and filters at RF and microwave frequencies. The topics
covered include measurement techniques for the characterization of tunable
dielectrics at low and microwave frequencies, fabrication processes, electrical and
acoustic modeling of thin film ferroelectric varactors, performance optimization
using conductive electrodes, realization of tunable microwave circuits and integration
of tunable dielectrics with conventional bulk acoustic wave resonators
(FBAR). Cont/d.
The work presented in this thesis focuses on the synthesis of nanomaterials, formulation and
printing of Ag nanoparticle and nanowire inks for two distinct applications: a) inkjet printing
of Ag nanoparticle films on ceramic substrates with the aim of providing a smaller size of
printed feature at lower cost than that can be obtained with the conventionally used screen
printing, and b) Ag nanowires films prompted by the wide quest of electronics industry for
materials with increased flexibility, lower cost and higher transmittance to replace indium tin
oxide.
Ag nanoparticles with a size of 50 nm were successfully synthesized and dispersed in
aqueous medium. Two preparation routes were compared in order to distinguish the effects of
solvents treatment of particles and their influence on the suspension characteristics including
Ag loadi...
The potential of algal biofuels has been technically and experimentally confirmed
with laboratory- and pilot-scale studies in past literature. However, the most
important factor now is to confirm that algal cultivation for biofuels and other
end-products is economically feasible on the large, commercial scale. The
ALGADISK project aimed to produce a novel biofilm-based photo-bioreactor
with the aims of CO2 capture and making valuable products such as biofuel,
economically viable. This thesis aimed to investigate and provide substrates in
which algae biofilm is stimulated and increased. Polyelectrolyte (PE) coatings
adsorbed onto cost-effective polymers were investigated, based on the strategy of
electrostatic attraction. It was found that the algae species charge density and cell
wall functional groups composition affected attachment o...
Energy harvesting; that is, harvesting small amounts of energy from environmental
sources such as solar, air flow or vibrations using small-scale (≈1cm
3
) devices, offers the
prospect of powering portable electronic devices such as GPS receivers and mobile
phones, and sensing devices used in remote applications: wireless sensor nodes, without
the use of batteries. Numerous studies have shown that power densities of energy
harvesting devices can be hundreds of µW; however the literature also reveals that power
requirements of many electronic devices are in the mW range. Therefore, a key challenge
for the successful deployment of energy harvesting technology remains, in many cases,
the provision of adequate power. This thesis aims to address this challenge by
investigating two methods of enhancing the power output of a piezoelectric-bas...
Patch clamping is considered the gold standard in measuring the bioelectrical activity of a cell. It is used to detect and measure ion transport through ion channels located throughout a cell membrane. Ion movement is crucial to cell viability and cell-to-cell communication. Pharmaceutical companies increasingly target ion channels because of their significance in disease and to help design better targeted drugs. However, the traditional method of patch clamping is cumbersome and is being replaced by planar high throughput screening (HTS) systems. These systems are reaching their limits due to materials and cost of processing; cell handling methods and small varieties of applicable cell types are also issues to be addressed.
In this work, the core components of a new kind of planar patch clamping device have been designed and developed...
Ferroelectric perovskite thin films for voltage tunable applications, namely (Ba,Sr)TiO3 (Barium Strontium Titanate or BST) and (Pb,Sr)TiO3 (Lead Strontium Titanate or PST), are synthesized via the so-called sol-gel route. While BST shows the tendency to severe film cracking, PST can be grown crack free onto platinised Si standard substrates and even directly onto SiO2, SiNx or bare Si.
The growth kinetics of PST on platinised SiO2/Si and directly on SiO2/Si are studied in detail using X-ray diffractometry (XRD), scanning electron and atomic force microscopy, SEM and AFM respectively. It is shown that PST begins to crystallise at 500°C on Ti/Pt and 550°C directly on SiO2. After a thermal treatment of 650°C for 15 min both films are fully crystallised with random (100) and (110) orientation and a smooth surface.
The dielectric propertie...
This PhD project aims to develop lead-free thin-film dielectric materials for fixed value, voltage tunable and high-k zipping variable capacitors using growth techniques that can be scaled for silicon batch fabrication. The thesis specifically details the growth and characterisation of barium zirconate titanate (BZT) and bismuth zinc niobate (BZN) dielectric thin films. Fixed value and tunable capacitors have been realised through the use of low and high permittivity dielectric thin film materials in both the amorphous and crystalline states. Planar devices fabricated using BZT and BZN dielectric thin films were grown by sol-gel and RF magnetron sputtering, respectively. The effects of different bottom electrodes were also investigated. Capacitors in a metal-insulator-metal (MIM) [metal-ferroelectric-metal (MFM) for BZT] structure have...
