Solid-State Tunneling Spectroscopy Of Individual Quantum Dots,
2010
University of Texas at Arlington
Solid-State Tunneling Spectroscopy Of Individual Quantum Dots, Ramkumar Subramanian
Material Science and Engineering Dissertations - Archive
Quantum dots are gaining importance for their potential applications in the fields of energy harvesting, bio-labeling and treatment, in opto-electronic devices and in photonic devices. For all these applications, it is imperative to know their electronic structure. Although currently several spectroscopic techniques exist to study the electronic structure of these quantum dots, they are accompanied by other effects and do not give purely the electronic structure of the individual quantum dot. The main goals of this research are to:o To study the energy level structure of `single' quantum dots.o Develop a new spectroscopic technique that allows the measurement of the …
Transmission Electron Microscopy Studies Of Lamno₃ And La₁₋Xsrxmno₃Thin Films Grown On Various Substrates,
2010
University of Texas at Arlington
Transmission Electron Microscopy Studies Of Lamno₃ And La₁₋Xsrxmno₃Thin Films Grown On Various Substrates, Yinsheng Fang
Material Science and Engineering Theses - Archive
LaMnO₃ (LMO) and La₁₋xSrxMnO₃ (LSMO) thin films with colossal magnetoresistance have attracted considerable interest for potential applications in many technological devices, such as magnetic sensors and read-head of computer memory. In this work, polycrystalline and epitaxial LMO and LSMO thin films were deposited on various substrates including (001) Si, (001) MgO, and (001) LaAlO₃ (LAO) using RF magnetron sputtering. The microstructures of the thin films were initially studied using X-ray diffraction. Detailed microstructure information such as crystallite of the films, grain size, epitaxial quality, crystallographic structure and film/substrate interface were studied using high-resolution transmission electron microscope (HRTEM). More specifically, Effects …
Characteristics Of Proton Conducting Pva-Chitosan Polymer Blend Electrolytes.,
2010
Universiti Malaya
Characteristics Of Proton Conducting Pva-Chitosan Polymer Blend Electrolytes., Mohd Fakhrul Zamani Abdul Kadir
Student Works (2010-2019)
The main focus of this present work is to build a good conducting solid polymer electrolyte (SPE) based on chitosan and poly(vinyl alcohol)(PVA) blend. Solution cast technique has been employed to produce sample films in this work. From the scanning electron micrographs (SEM) the surface morphology of the blend containing 40 wt.% chitosan and 60 wt.% PVA (C4P6) is homogenous and miscible in one and another. The C4P6 film is the most amorphous and is the best candidate for the polymer host in the electrolyte systems studied in the present work. Ammonium Nitrate (NH4NO3) is the doping salt that provides …
Mechanical And Thermodynamic Properties Of Bacteriorhodopsin Langmuir Film.,
2010
Universiti Malaya
Mechanical And Thermodynamic Properties Of Bacteriorhodopsin Langmuir Film., Vijayandren Kuppusamy
Student Works (2010-2019)
Bacteriorhodopsin is a photoactive protein found in the purple membranes of the highly halophilic bacterium Halobacterium Salinarium. Due to highly efficient and simple in its function, Bacteriorhodopsin has been extensively researched and successfully incorporated into many practical applications. In this regard, the fabrication of compactly packed and functionally active Bacteriorhodopsin thin film is crucial in realizing a highly efficient device. The aim of this thesis is to analyze the mechanical and thermodynamic properties of the Bacteriorhodopsin-Langmuir monolayer film from the surface pressure-area per molecule isotherm to produce a compactly pact and functionally active monolayer film. For this, we have proposed …
Electrodeposition Of Tin Using Tin (Ii) Methanesulfonate From Mixture Of Ionic Liquid And Methane Sulfonic Acid.,
2010
Universiti Malaya
Electrodeposition Of Tin Using Tin (Ii) Methanesulfonate From Mixture Of Ionic Liquid And Methane Sulfonic Acid., Yang Kok Kee
Student Works (2010-2019)
The electrodeposition of tin from Tin(II) Methane Sulfonate (MSA) with varying concentration in air and water stable 1-butyl-1-methyl-pyrrolidinium trifluoromethanesulfonate, (BMPOTF) ionic liquid at room temperature was studied. Cyclic Voltammetry served to characterize the electrochemical behavior of tin reduction and oxidation. The diffusion coefficient of stannous ions in the mixture of BMPOTF ionic liquid and MSA based electrolyte obtained via Randles-Sevcik and Cottrell equation was 2 × 10-7 cm2/s. Electroplating on copper panel was conducted under different current densities to determine BMPOTF based tin plating solution current efficiency. Mixture of BMPOTF and MSA based tin plating solution gave current efficiency as …
Synthesis And Characterization Of Zinc Oxide Nanostructures.,
2010
Universiti Malaya
Synthesis And Characterization Of Zinc Oxide Nanostructures., Khalifa Said Zahran Al-Azri
Student Works (2010-2019)
The growth mechanism, morphology, structure and optical properties of the ZnO nanostructures grown on bare and gold-coated silicon substrates using carbothermal reaction at atmospheric pressure were investigated under different growth conditions. The ZnO nanostructures formed were studied as a function of substrate location, furnace temperature, Ar gas flow rate, deposition time and ZnO powder to carbon powder mass ratio. The morphology and structure of the samples were characterized using the fieldemission scanning electron microscopy (FESEM), energy dispersive x-ray spectroscopy(EDX) spectrum, x-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). It was found that in both silicon and gold-coated silicon …
Thermo-Electrical And Mechanical Studies On Polymer-Organically Modified Montmorillonite Composite.,
2010
Universiti Malaya
Thermo-Electrical And Mechanical Studies On Polymer-Organically Modified Montmorillonite Composite., Norhana Abdul Halim
Student Works (2010-2019)
The field of polymer-nanoclay composite has attracted a lot of attention in materials studies due to the dramatic improvement on polymers characteristics. For example mechanical and thermal properties, chemical resistance as well as the reduced gas permeability. However, structural changes and the mechanisms that may contribute to these improvements are not fully understood. In this work, the study on polymer nanoclay composite concentrates on the effects of OMON inclusion within different polymer matrix systems. The matrixes are a series of natural rubbers (Standard Malaysia Rubber – Latex grade (SMRL); Deproteinized Natural Rubber (DPNR) and Epoxidized Natural Rubber (ENR-50)), plasticized Polyvinyl …
Electrical And Structural Studies Of Polyacrylonitrile (Pan) Complexed With Inorganic Salts.,
2010
Universiti Malaya
Electrical And Structural Studies Of Polyacrylonitrile (Pan) Complexed With Inorganic Salts., Khairul Bahiyah Md Isa
Student Works (2010-2019)
In the present study, polymer electrolyte films composed of polyacrylonitrile (PAN) as a host polymer, ethylene carbonate (EC) as the plasticizer and lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3) as dopant salts were prepared by the solution cast technique. Five systems of polymer electrolytes films have been prepared; these systems are the plasticized-PAN system i.e. PAN-EC system, two salted-PAN systems i.e. PAN-LiCF3SO3 and PAN-NaCF3SO3, and two plasticized-salted PAN systems i.e. PAN-EC-LiCF3SO3 and PAN-EC-NaCF3SO3. The pure PAN film was prepared as a reference. The ionic conductivity for each system is characterized using impedance spectroscopy. The room temperature conductivity of the pure …
The Thermoluminescence Properties Of Manganese Doped Zns Nanophosphor.,
2010
Universiti Malaya
The Thermoluminescence Properties Of Manganese Doped Zns Nanophosphor., Khalid Humaid Zahir Al-Hinai
Student Works (2010-2019)
The thermoluminescence (TL) properties of Manganese (Mn) doped ZnS nanophosphors were investigated after gamma irradiation at room temperature. The ZnS:Mn nanophosphors were prepared by chemical precipitation method by using Zinc sulfate, Sodium sulfide and Manganese sulfate. 1 mole, 2 moles and 3 moles of Manganese sulfate were used to have different concentrations of Mn in doped ZnS. The formation of the nanophosphors was characterized by high resolution scanning electron microscopy FESEM, XRD and EDX. The obtained products consist of particles with the dimension about 85–150nm. Comparison between ZnS nanophosphors and commercial ZnS powder glow curves was studied. It was observed …
Band Structure Of Fe Based Superconductors.,
2010
Universiti Malaya
Band Structure Of Fe Based Superconductors., Teh Yee Lin
Student Works (2010-2019)
Several iron containing superconductors are discovered in 2008. The discovery introduced a new class of high-temperature superconductors, which are iron-based. The iron-based superconductors do not resemble conventional superconductors and have properties on their own which differ from the cuprates. We have studied the iron selenium, FeSe compound by removing some Se atoms from the lattice forming Fe:Se = 2:1 and 8:6 and also by replacing the Se vacancy with tellurium, samarium and oxygen atoms forming Fe:Se:Te = 2:1:1 and 8:6:2, Fe:Se:O = 8:6:2 and 8:4:2, FeSeSmO, FeSeTeO, Fe2SeSm2O2, FeSeTeSmO and FeTeSmO. The band structures for each lattice are calculated by …
Synthesis And Characterization Of Silicon Oxide And Silicon Carbide Nanostructures.,
2010
Universiti Malaya
Synthesis And Characterization Of Silicon Oxide And Silicon Carbide Nanostructures., Majid Salim Mohammed Al-Ruqieshi
Student Works (2010-2019)
Silicon oxide nanostructures have attracted extensive interests in recent years due to their physical and optical properties. SiOx nanostructures are synthesized by catalytic and non-catalytic approaches. With catalytic approach, long and uniform amorphous silicon oxide nanowires, nanofibers (comet and tree like), nanocakes and nanocages were synthesized on Si substrate by carbothermal evaporation reactions of TiO2 at high temperature. The SiOx nanowires were about 13 nm to 243 nm in diameters and 194 nm to several microns in length and the nanofibres with diameter between 8 nm to 30 nm and around 50 nm to 2.5μm in length. The diameter and …
Electrodeposition Of Tin Using Tin(Ii) Methanesulfonate From Mixture Of Ionic Liquid And Methane Sulfonic Acid.,
2010
Universiti Malaya
Electrodeposition Of Tin Using Tin(Ii) Methanesulfonate From Mixture Of Ionic Liquid And Methane Sulfonic Acid., Yang Kok Kee
Student Works (2010-2019)
The electrodeposition of tin from Tin(II) Methane Sulfonate (MSA) with varying concentration in air and water stable 1-butyl-1-methyl-pyrrolidinium trifluoromethanesulfonate, (BMPOTF) ionic liquid at room temperature was studied. Cyclic Voltammetry served to characterize the electrochemical behavior of tin reduction and oxidation. The diffusion coefficient of stannous ions in the mixture of BMPOTF ionic liquid and MSA based electrolyte obtained via Randles-Sevcik and Cottrell equation was 2 × 10-7 cm2/s. Electroplating on copper panel was conducted under different current densities to determine BMPOTF based tin plating solution current efficiency. Mixture of BMPOTF and MSA based tin plating solution gave current efficiency as …
Synthesis And Characterization Of Limpo[4] (M=Mn, Ni And Fe) Olivine Materials.,
2010
Universiti Malaya
Synthesis And Characterization Of Limpo[4] (M=Mn, Ni And Fe) Olivine Materials., Azlin Sanusi
Student Works (2010-2019)
Lithium transition metal phosphate, LiMPO4 compounds with olivine structure namely LiMnPO4, LiNiPO4 and LiFePO4 were successfully synthesized in the present work. LiMnPO4 and LiNiPO4 were synthesized by the sol-gel method with tartaric acid as the chelating agent. LiFePO4 was synthesized via the chemical precipitation and low temperature sterilizer heating method. TGA was carried out on LiMnPO4 and LiNiPO4 samples to determine the firing temperature of the gel precursor and the thermal stability of the prepared samples. LiMnPO4 was heated for 15 hours at various temperatures and LiNiPO4 was formed at 1000 oC with firing time of 24 hours. Firing of …
Inductively Coupled Plasma Dry Etching Process On Planar Lightwave Circuit Fabrication.,
2010
Universiti Malaya
Inductively Coupled Plasma Dry Etching Process On Planar Lightwave Circuit Fabrication., Chuah Khoon Seah
Student Works (2010-2019)
The main objective of this project is to master state-of-the-art techniques and knowledge in silica etching in order to achieve high quality waveguide circuit on Planar Lightwave Circuit devices. Another objective is to optimize the clean room research strength, surface characterization, microscopy techniques and similar semiconductor manufacturing processes.Initially, these processes were conducted with wet etching method that utilized diluted hydrofluoric acid (HF) and buffered oxide etch (BOE). Several problems arising such as mask peel-off, poor sidewall profile and defect waveguide channel during the pattern transfer process due to its’ isotropic nature. Alternatively, dry etching method was conducted via Inductively Coupled …
Strain-Stiffening In Synthetic And Biopolymer Networks,
2010
Purdue University
Strain-Stiffening In Synthetic And Biopolymer Networks, Kendra Erk, Kevin J. Henderson, Kenneth R. Shull
School of Materials Engineering Faculty Publications
Strain-stiffening behavior common to biopolymer networks is difficult to reproduce in synthetic networks. Physically associating synthetic polymer networks can be an exception to this rule and can demonstrate strain-stiffening behavior at relatively low values of strain. Here, the stiffening behavior of model elastic networks of physically associating triblock copolymers is characterized by shear rheometry. Experiments demonstrate a clear correlation between network structure and strain-stiffening behavior. Stiffening is accurately captured by a constitutive model with a single fitting parameter related to the midblock length. The same model is also effective for describing the stiffening of actin, collagen, and other biopolymer networks. …
Electrochemical Characterization Of Cerium-Based Conversion Coatings On Al 7075-T6,
2010
Missouri University of Science and Technology
Electrochemical Characterization Of Cerium-Based Conversion Coatings On Al 7075-T6, Simon Joshi
Doctoral Dissertations
"This research used electrochemical techniques to characterize the deposition and corrosion protection behavior of cerium-based conversion coatings on AI 7075-T6. Alkaline activation decreased native oxide impedance (5.9 kΩ-cm²) by ~25% promoting deposition of 250-500 mn coatings. Activation in NaOH solutions deposited coatings with large cracks and craters, whereas Na₂C0₃ activation resulted in uniform coatings, i.e., fewer cracks and almost no craters. Uniformly deposited coatings exhibited better cathodic inhibition and higher impedance (~200 kΩ-cm²) than on NaOH activated substrates (~100 kΩ-cm²). Subsurface crevices, caused by Cl⁻ and H₂O₂ in the deposition solution, were found under large cracks and craters. Thus, Na₂CO₃ …
Characterization Of The Corrosion Protection Mechanism Of Cerium-Based Conversion Coatings On High Strength Aluminum Alloys,
2010
Missouri University of Science and Technology
Characterization Of The Corrosion Protection Mechanism Of Cerium-Based Conversion Coatings On High Strength Aluminum Alloys, William R. Pinc
Doctoral Dissertations
"The aim of the work presented in this dissertation is to investigate the corrosion protection mechanism of cerium-based conversion coatings ( CeCCs) used in the corrosion protection of high strength aluminum alloys. The corrosion resistance of CeCCs involves two general mechanisms; barrier and active. The barrier protection mechanism was influenced by processing parameters, specifically surface preparation, post-treatment, and the use of gelatin. Post-treatment and the addition of gelatin to the coating solution resulted in fewer cracks and transformation of the coating to CeP0₄, which increased the corrosion resistance by improving the barrier aspect of CeCCs. CeCCs were found to best …
Fluid Flow Related Phenomena And Inclusion Motion In Continuous Casting Strands,
2010
Missouri University of Science and Technology
Fluid Flow Related Phenomena And Inclusion Motion In Continuous Casting Strands, Yufeng Wang
Doctoral Dissertations
"To improve the efficiency of the continuous casting process and the quality of its products, this dissertation mainly investigated fluid flow related phenomena and inclusion motion in continuous casting. Mathematical simulation was performed for this purpose. Both a slab caster and a billet caster were investigated. In the study of the slab caster, the application of electromagnetic brake field on the slab mold was evaluated. The results indicated that the magnetic force decelerated the high speed steel jet, stabilized the top fluctuation, and prevented the bias flow inside the mold. The other study of this slab caster involved the fluid …
Investigation Of The Thermoelectric Behavior Of Cu-Doped Pbteagxse,
2010
Clemson University
Investigation Of The Thermoelectric Behavior Of Cu-Doped Pbteagxse, Ben Ma
All Theses
Sustainable energy research is currently on the forefront of scientific exploration thus a major effort is devoted to the development of new energy conservation and production techniques. Thermoelectric materials can play a significant part both in energy conservation and energy production via the Seebeck effect (heat to electric power) and the Peltier effect (electricity to cooling power), since they can convert wasted heat to useful electrical energy.
Presented herein are the measured electrical and thermal transport properties and phenomenal analysis of the PbTeAgxSe (x=1.9, 2.0, 2.01) system. First, it would lead to a significant reduction in the thermal conductivity and …
Giant Raman Enhancement On Nanoporous Gold Film By Conjugating With Nanoparticles For Single-Molecule Detection,
2010
University of Nevada, Las Vegas
Giant Raman Enhancement On Nanoporous Gold Film By Conjugating With Nanoparticles For Single-Molecule Detection, Lihua Qian, Biswajit Das, Yan Li, Zhilin Yang
Electrical & Computer Engineering Faculty Research
Hot spots have the contradictively geometrical requirements for both the narrowest interstices to provide strong near-field coupling, and sufficient space to allow entrance of the analytes. Herein, a two-step method is employed to create hot spots within hybrid nanostructures, which consist of self-supported nanoporous gold films with the absorbed probes and subsequent nanoparticle conjugates without surface agents or mechanical motion. The molecules confined into 1 nm interstice exhibit 2.9 × 107 times enhancement in Raman scattering compared to pure nanoporous gold. Giant enhancement primarily results from strong near-field coupling between nanopore and nanoparticle, which is theoretically confirmed by finite-difference …
