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Theses/Dissertations

2009

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Articles 1 - 9 of 9

Full-Text Articles in Nanoscience and Nanotechnology

Monitoring Of Immune Cell Response To B Cell Depletion Therapy And Nerve Root Injury Using Spio Enhanced Mri, Daniel L. Thorek Dec 2009

Monitoring Of Immune Cell Response To B Cell Depletion Therapy And Nerve Root Injury Using Spio Enhanced Mri, Daniel L. Thorek

Publicly Accessible Penn Dissertations

Magnetic resonance (MR) is a robust platform for non-invasive, high-resolution anatomical imaging. However, MR imaging lacks the requisite sensitivity and contrast for imaging at the cellular level. This represents a clinical impediment to greater diagnostic accuracy. Recent advances have allowed for the in vivo visualization of populations and even of individual cells using superparamagnetic iron oxide (SPIO) MR contrast agents. These nanoparticles, commonly manifested as a core of a single iron oxide crystal or cluster of crystals coated in a biocompatible shell, function to shorten proton relaxation times. In MR imaging these constructs locally dephase protons, resulting in a decrease ...


Synthesis And Spectroscopic Characterization Of Nanostructured Thermoelectric Materials, Jason Reppert Dec 2009

Synthesis And Spectroscopic Characterization Of Nanostructured Thermoelectric Materials, Jason Reppert

All Dissertations

Bismuth in the bulk form is a semimetal with a rhombohedral structure. It has a small band overlap between the conduction and valence bands and a highly anisotropic electron effective-mass tensor. Thermoelectric materials, in which one of the three dimensions is in the nanometer regime, exhibit unique quantum confinement properties and have generated much interest in recent years. Theoretical investigations have suggested that nanowires with diameters ≤ 10 nm will possess a figure-of-merit ZT > 2. Prior to this study, it has been shown that Bi nanowires with small enough diameters (~10 nm), prepared via the pulsed laser vaporization method, undergo a ...


Inter-Tube Bonding And Defects In Carbon Nanotubes And The Impact On The Transport Properties And Micro-Morphology, Keqin Yang Dec 2009

Inter-Tube Bonding And Defects In Carbon Nanotubes And The Impact On The Transport Properties And Micro-Morphology, Keqin Yang

All Dissertations

The transport properties of the carbon nanotubes (CNTs) are affected by the tube-tube interaction and the defects presented in the system. Inter-tube bonding, formed during spark plasma sintering (SPS) process, lowers the electrical/thermal resistivity at the tube-tube junctions and also causes new scattering mechanisms such as strong electron-phonon coupling (EPC) at low temperature. More evidences have been found by changing the SPS temperature and doping the CNTs to support the electron-phonon coupling is Kohn anomaly (KA) in as-SPSed CNTs. The phonon drag, appearing in thermoelectric power (TEP) of the as-SPSed CNTs at low temperature, can be explained in the ...


Modulated Nanopores Using Pulse Anodization On Thin Aluminum, Mahesh Babu Gunukula May 2009

Modulated Nanopores Using Pulse Anodization On Thin Aluminum, Mahesh Babu Gunukula

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nanoporous anodic aluminum oxide has traditionally been made in one of two ways: "Mild Anodization (MA)" or "Hard Anodization (HA)". The former method produces self-ordered pore structures but it is slow and only works for a narrow range of processing conditions; the latter method, which is widely used in the aluminum industry, is faster but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the MA and HA processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic ...


Magnetic Sensors For Biodetection, Pranjali Vineet Sneha Deshpande May 2009

Magnetic Sensors For Biodetection, Pranjali Vineet Sneha Deshpande

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of thesis is to design magnetic sensor for detection of nanoparticles. Recently integrating the standard laboratory techniques into integrated system on chip is growing attention. Recent development is to combine magnetic markers and magnetoresistive sensors together in magnetic chip. In this thesis two magnetoresistive sensors were studied and designed.

By applying magnetic fields, magnetic nanoparticles can be manipulated on-chip, which can be utilized to pull the molecules to specific binding sites or to test the binding strength and distinguish between specifically and non-specifically bound molecules

Magnetoresistive sensors are compatible with the semiconductor industry which provides electronic signal directly ...


Spectroscopic Investigation Of Palladium-Copper Bimetallic Systems For Pem Fuel Cell Catalysts, Timo Hofmann Jan 2009

Spectroscopic Investigation Of Palladium-Copper Bimetallic Systems For Pem Fuel Cell Catalysts, Timo Hofmann

UNLV Theses, Dissertations, Professional Papers, and Capstones

One of the main barriers to commercialization of polymer electrolyte membrane fuel cells systems is cost, which is largely due to the need of platinum (Pt)-containing catalysts. In this thesis we investigate bimetallic systems consisting of a base metal (copper) and a noble metal (palladium) that, as an alloy on the nanoscale, mimic the electronic properties that make Pt desirable as a catalyst.

We present a detailed investigation of the electronic structure of carbon-supported Pd/Cu nanoparticle catalysts, model bilayer thin film systems, alloys, and various metal reference samples. We have investigated the valence band structure of the catalysts ...


Substituent Effect On The Electronic And Assembling Properties Of Asymmetric Phenazine Derivatives, Bin Cao Jan 2009

Substituent Effect On The Electronic And Assembling Properties Of Asymmetric Phenazine Derivatives, Bin Cao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Currently, one-dimensional (1-D) nanostructures have drawn much interest because of their potential applications for nanoscale optoelectronic devices. Self-assembly (SA) based on π-conjugated systems through various intermolecular interactions has been widely used to produce 1-D nanostructure. Morphology of the assembled structures can be modified by incorporating substituents, which provide additional secondary interactions. Meanwhile, those substituents also influence the electronic properties of the molecules. Previous studies have made little effort to systematically study subsistent effects on both electronic and SA properties.

The primary objective of this research is to generate controllable 1-D structures through SA, and to provide a fundamental understanding of ...


Metal Induced Crystallization Of Silicon Thin Films, Sandeep Kumar Raju Sangaraju Jan 2009

Metal Induced Crystallization Of Silicon Thin Films, Sandeep Kumar Raju Sangaraju

UNLV Theses, Dissertations, Professional Papers, and Capstones

Low temperature crystallization of thin film silicon is important for many industrial applications including flat panel displays and silicon thin film solar cells. Unfortunately this remains a major challenge since crystallization temperature of silicon is above 1,000 degrees Celsius, thus limiting to substrates that can tolerate high temperatures. The inability to deposit crystalline thin films on glass substrates is the reason why flat panel display industry uses amorphous silicon for LCD active matrix displays. Thus the ability to deposit crystallized thin film silicon at low temperatures will have significant impact on thin film silicon applications. It has been observed ...


Characterization Of A Viscoelastic Response From Thin Metal Films Deposited On Silicon For Microsystem Applications, Steven L. Meredith Jan 2009

Characterization Of A Viscoelastic Response From Thin Metal Films Deposited On Silicon For Microsystem Applications, Steven L. Meredith

Master's Theses and Project Reports

Understanding the mechanisms that control the mechanical behavior of microscale actuators is necessary to design an actuator that responds to an applied actuation force with the desired behavior. Micro actuators which employ a diaphragm supported by torsional hinges which deform during actuation are used in many applications where device stability and reliability are critical. The material response to the stress developed within the hinge during actuation controls how the actuator will respond to the actuating force. A fully recoverable non-linear viscoelastic response has been observed in electrostatically driven micro actuators employing torsional hinges of silicon covered with thin metal films ...