The ionization of xenon Rydberg atoms at metallic surfaces is examined. The data show that, when the effects of stray electric "patch" fields present on the surface are taken into account, ionization is well described by a simple over-the-barrier model. The patch fields are determined from direct measurements of the potential variations across the target surfaces using Kelvin probe force microscopy. Monte Carlo techniques are used to model the atom-surface interaction. The results confirm the important role that patch fields can play during Rydberg atom-surface interactions and suggest that such interactions can provide a sensitive probe of stray fields at surfaces. To demonstrate this, measurements of the threshold conditions required to observe ions resulting from surface ionization are used to estimate how large such stray fields can be. The data show that the stray fields can be sizable, as large as ∼ 10 3 V · cm -1 100 nm from the surface and ∼ 10 V · cm -1 500 nm from the surface, and illustrate the potential of Rydberg atoms for detecting and characterizing surface electric fields. Methods to enhance the surface ionization signal using electrode arrays patterned on a surface are investigated. Simulations show that bias voltages applied to a series of parallel wires comprised of two interleaved comb-shaped electrodes can have a dramatic impact on ion collection efficiency. It is suggested that such a surface can be used to efficiently collect low- n Rydberg atoms ( n [Special characters omitted.] 10). Significant progress towards fabrication of a functioning surface of 1 μm wide wires with 1 μm spacing is documented.

Electrical conductive adhesives (ECAs) containing silver filler and polyaniline co-filler were characterized for their electro-mechanical properties. Polyaniline is a conductive polymer and has a moderate conductivity in between those of the silver and epoxy. Incorporation of polyaniline (μm sized) in silver-epoxy facilitated the electrical conduction in ECAs and reduced the percolation threshold- a minimum volume of filler necessary to initiate the conduction. It also prevented the localization of charge carriers due to aggregation of silver filler particles. ‘Bridging effect’ was observed due to addition polyaniline in which the polyaniline enhanced the tunneling of electrons over the silver filler particles. We have investigated the polyaniline co-fillers as a promising alternative way to tune the mechanical and electrical properties of the ECAs and have provided a detailed analysis of the electro-mechanical properties of silver-epoxy (Ag-epoxy) and silver-polyaniline-epoxy (Ag-PANI-epoxy) system in both partially-cured/ viscoelastic and fully-cured states. Analysis of electro-mechanical properties of silver-epoxy and silver-polyaniline-epoxy also provided the insights into electrical contact resistance of ECAs under compressive force. Electro-mechanical properties of ECAs were measured ‘in-situ’ using micro-indentation technique. We also synthesized the electrically conductive and highly crystalline nanotubes of polyaniline by mini-emulsion polymerization of aniline. The motivation behind the synthesis of polyaniline was to propose a potential filler/co-filler for replacement of metallic filler in ECAs. Electrical conductivity of polyaniline nanotubes was tuned by in-situ doping using hydrochloric acid as a dopant. Increase in dopant caused the polyaniline crystallite to grow along (400) plane. Optical, structural, electrical and thermal properties of polyaniline nanotubes are reported with varying amount of dopant. We fabricated the flexible electrically conductive coating of polyaniline tubes with uniform dispersion of polyaniline. Electrical performance of as-synthesized flexible coating is also revealed.

The purpose of this study is to investigate the most common phonetic and phonological difficulties in the teaching of Spanish as a foreign language. The study has been based on the following questions: Which difficulties can teachers encounter when teaching phonetics and phonology? Which difficulties can students encounter when learning phonetics and phonology? How is phonetics and phonology taught? In order to be able to investigate the difficulties, a questionnaire has been handed out to five experienced teachers. The results of the questionnaires, together with the theory, has been analysed in the analysis. The outcome of the analysis shows that several difficulties can be detected in both the teaching and in the learning process. The results of the questionnaires also show us that the teachers mostly teach phonetics the same way: through repetition and imitation, the conductive method, and very few think outside of the box to encounter new methods.

The goal of the thesis is to incorporate materials with either fluorescent or conductive properties in silk fibers, by feeding silkworms with a diet containing these materials. To achieve this, one would have to breed (rear) silkworm from eggs into larvaes, then to feed the silkworms with this special diet containing fluorescent or conductive materials. Samples of silk were then collected either from spun cocoons or via removing the silk producing organs (silk glands) from the silkworms via dissection. The samples were then analyzed with absorbance spectrometer, spectrofluorometer or via photoluminesecent measurement to determine if any materials had been incorporated into the silk fibers.   Silkworms were successfully reared from eggs up to moths, once the silkworm larvae had grown enough in size their diet were switches from their regular food (silkworm chow) to food containing conjugated molecules or polymers with fluorescent or conductive properties. A total of 14 materials were tested. One material gave a clear positive result and that was from the fluorescent compound Rhodamine B. Other fluorescent materials, Nile red and POWT yielded some results indicating their presence in the silk but the results were not conclusive. The rest of the materials all failed with being incorporated within the silk fibers; this was due to their lethality, size, lack of zwitterionic properties and such.  The properties of the materials are of great importance for the uptake process, where a small zwitterionic molecule has a great change of being taken up and incorporated in the silk fibers. Whereas a big materials such as a polymer without any zwitterionic will in most cases just follow through the food in the digestive track without any uptake.

This thesis presents a comparative study between two silver nanoparticle inks that were deposited using a Drop-on-Demand (DoD) inkjet printer, aiming at finding a functional ink that can be used to print electrodes in Light-emitting Electrochemical Cells (LECs). To achieve this, a DoD inkjet printer was installed and an acquaintance with the printer was attained. Among the two inks, one was employed as received while the other was reformulated, and successful deposition of both the inks was observed. During the reformulation process, it was seen that the highly volatile tetrahydrofuran (THF) solvent can be used to improve the ink properties, in contrast to what is recommended. After that, the inks were deposited on UV-ozone treated glass substrates, sintered at an elevated temperature under ambient conditions, and their specific resistances and thicknesses were measured. Finally, the inks were used to print the anode in a structured sandwich-cell LEC. The performance comparison was conducted by observing the emitted light of the LECs. The results indicate that the reformulated ink performs better, probably due to the lower silver concentration that results in flatter surface, which in turn effectively alleviates shorts.

Polymer electrolyte membrane fuel cells (PEMFCs) have the potential to play a major role as energy generators for transportation and portable applications. One of the current barriers to their commercialization is the cost of the components and manufacturing, specifically the bipolar plates. One approach to preparing PEMFCs for commercialization is to develop new bipolar plate materials, related to mass production of fuel cells. Thermoplastic/carbon filler composites with low filler loading have a major advantage in that they can be produced by a conventional low-cost injection molding technique. In addition, the materials used are inexpensive, easy to shape, and lightweight. An optimal bipolar plate must possess high surface and bulk electronic conductivity, sufficient mechanical integrity, low permeability, and corrosion resistance. However, it is difficult to achieve high electrical conductivity from a low-cost thermoplastic composite with low conductive filler loading. Concerns over electrical conductivity improvement and the injection processability of composites have brought forth the idea of producing a polypropylene/three-carbon-filler composite for bipolar plate application. The thesis addresses the development of synergistic effects of filler combinations, investigating composite conductive materials and using composite bipolar plate testing in PEMFCs. One significant effect of conductive network formation is the synergetic effects of different carbon filler sizes, shapes, and multiple filler ratios on the electrical conductivity of bipolar plate materials. A polypropylene resin combined with low-cost conductive fillers (graphite, conductive carbon black, and carbon fibers with 55 wt% of filler loading) compose the main composite for all investigations in this research. Numerous composite formulations, based on single-, two-, and three-filler systems, have been created to investigate the characteristics and synergistic effects of multiple fillers on composite conductivity. Electrical conductivity measurements corresponding to PEMFC performance and processing characteristics were investigated. Experimental work also involved other ex-situ testing for the physical requirements of commercial bipolar plates. All combinations of fillers were found to have a significant synergistic effect that increased the composite electrical conductivity. Carbon black was found to have the highest influence on the increase of electrical conductivity compared to the other fillers. The use of conjugated conducting polymers such as polypyrrole (PPy) to help the composite blends gain desirable conductivities was also studied. Electrical conductivity was significantly improved conductivity by enriching the conducting paths on the interfaces between fillers and the PP matrix with PPy. The conductive network was found to have a linkage of carbon fibers following the respective size distributions of fibers. The combination of Fortafil and Asbury carbon fiber mixture ameliorated the structure of conductive paths, especially in the through-plane direction. However, using small fibers such as carbon nanofibers did not significantly improve in electrical conductivity. The useful characteristics of an individual filler and filler supportive functions were combined to create a novel formula that significantly improved electrical conductivity. Other properties, such as mechanical and rheological ones, demonstrate the potential to use the composites in bipolar plate applications. This research contributes a direction for further improvement of marketable thermoplastic bipolar plate composite materials.

Heterocyclic organic and organometallic compounds (e.g. polypyrrole) and their derivatives have been of great interest for conductive polymers due to their novel properties and environmental stability as compared to non-aromatic analogs (e.g. polyacetylene). We are interested in synthesizing organometallic pyridazines and rhenium pyridazyl complexes for polymer research. SeveraI5,6-fused ring pyridazines (1,2-CsH3(CRNH)(CRN) have been synthesized and characterized. Additionally, pyridazyl complexes of rhenium were synthesized in three steps beginning from fulvenes 1,2-CsH3(COHR)(COR). On-Metal synthesis and characterization of (Re(CO)3 {1,2- CSH3(CRN)(CRN)}] (R=C6RtOMe, C6RtCI, C4H30) and some off-metal pyridazines are reported here. Our research is focused on synthesis of a variety of 5,6- fused ring pyridazines which will serve as synthetic models and building blocks for organic and organometallic conducting polymers. Our research focused on synthesis of 5 membered pyridazines and their organometallic rhenium complexes for polymer studies. Several aryl-substituted 5,6- fused ring pyridazines have been synthesized and characterized.

A novel mirror finishing method using a conductive polymer as the tool electrode is presented. It has been known that the conductive polymers have many advantages, such as to conduct a micro-current, to be easily processed into various shapes, to hold abrasives, and to have an excellent wear resistance. The effects of particle size, machining time, concentration of electrolyte, working current, and load on the surface roughness and the removal depth of SUS-304 stainless steel are investigated.When the operative parameters are set for the particle size of 3 £gm, the concentration of electrolyte of 10 wt%, the working current ranged from 10 to 20 mA, and the load of 10 N, the surface roughness Rmax, which originally is 1.4 £gm, can be reduced to 0.17~0.24 £gm after the machining time of 3 min. The surface roughness Ra can be achieved to 7.897 nm under the optimal condition. In addition, experimental results show that there is an optimal region of the working current at the concentration of electrolyte of 10 wt%. According to the surface profiles and SEM micrographs, three machining regions can be classified as (1) the mechanical polishing region, (2) the electro-chemical buffing (ECB) region, and (3) the excessive corrosion region. To achieve a high-quality mirror-like surface, the machining region must be operated at the ECB region.

In this thesis, the contact behavior of the conduct particles in the anisotropic conductive film (ACF) packaging process is investigated. The thermal elastic-plastic finite element (FE) model is employed to simulate the contact process. The commercial MARC finite element method package is used in this work. Two contact models of the ACF packaging are studied : the single particle and the multiple-particles models. In the single particle model a simple axial symmetric FE model is used to simulate the variation of elastic-plastic deformations during packaging process. The effect of coating thickness on the contact deformation is discussed. To explore the effect of particle distribution on the contact deformation and the conduct behavior in the ACF packaging, the multiple-particles 3D model has also been studied. However, to overcome the computing difficulties introduced from huge degrees of freedom, the equivalent nonlinear springs are employed to stand for some conductive particles. The effect of particle distribution and particle parameters on the conductive behavior are studied. Results indicate that the conductive particle parameters may affect the conductive characteristics significantly in the ACF packaging process.

As the IC assembly technology fast developing in the modern electrical industries. Demand of high performance electric product is glowing up day by day. New generation of the hybrid IC assembly package has become the major role recently. In order to prevent the package defects occurring in end customer sites, in this paper we try to improve the IC assembly method by using a totally different process to fix the passive component on a BGA substrate. We found that the passive component can be proceeded the current gold wire bonding process. In case of the Hybrid BGA with the current passive component attaching process, we can find the thermal effect during the surface mount process. Since the solder can be melt every time during each heating process. Therefore, we plan to improve it without solder attachment. The new improvement is to fix the passive component by a non-conductive thermal cure glue. The glue can be done in one time cure, thus the further process would not influence the quality of passive component. However in the evaluation experiment, the component coated by Gold is the best choice, but we intend to just put it in a comparison model because of the cost consideration. Both works on passive component coated by Gold and Solder were proved. The customer support for the further study on the real products is suggested.