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Full-Text Articles in Physics

Methods For Producing Graphene From Petroleum By-Products, Eva M. Deemer Jan 2017

Methods For Producing Graphene From Petroleum By-Products, Eva M. Deemer

Open Access Theses & Dissertations

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Raman Microscopic Analysis Of Internal Stress In Boron-Doped Diamond Thin Films, Emma M.A. Sundin Jan 2017

Raman Microscopic Analysis Of Internal Stress In Boron-Doped Diamond Thin Films, Emma M.A. Sundin

Open Access Theses & Dissertations

The correlations between induced stress on undoped and boron-doped diamond (BDD) thin films, sample chemical composition, and fabrication substrate are investigated in this study via confocal Raman microspectroscopic analysis. Stability of BDD films is relevant to fast-scan cyclic voltammetry, as film delamination and dislocation of BDD-coated electrodes that can occur during neurosurgical electrode implantation can negatively impact the biosensing reliability of this technique. Electrodes were fabricated by coating cylindrical tungsten rods using a custom-built chemical vapor deposition reactor. The results of the analysis reveal a direct correlation between regions of pure diamond and enhanced material stress, as well as preferential …


Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc Jan 2017

Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc

Open Access Theses & Dissertations

Methods built on Raman spectroscopy have shown major potential in describing and discriminating between malignant and benign specimens. Accurate, real-time medical diagnosis benefits in substantial improvements through this vibrational optical method. Not only is acquisition of data possible in milliseconds and analysis in minutes, Raman allows concurrent detection and monitoring of all biological components. Besides validating a significant Raman signature distinction between non-tumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, this study reveals a label-free method to assess overexpression of epidermal growth factor receptors (EGFR) in tumor cells. EGFR overexpression sires Raman features associated with phosphorylated threonine and serine, and …


Ac Susceptibility And Epr Investigations Of Superspin Dynamics In Manganese Oxide Nanoparticles, Mahesh Koirala Jan 2017

Ac Susceptibility And Epr Investigations Of Superspin Dynamics In Manganese Oxide Nanoparticles, Mahesh Koirala

Open Access Theses & Dissertations

We have investigated the superspin dynamics of 5 nm and 10 nm mixed state Mn3O4 nanoparticles utilizing ac-susceptibility and electron paramagnetic resonance measurements. The out of phase component of the ac-susceptibility measurements show a magnetic anomaly below (T


Dft Study Of Adsorption Of Trimetallic Endohedral Fullerenes On Graphene, Nakul Nitin Karle Jan 2017

Dft Study Of Adsorption Of Trimetallic Endohedral Fullerenes On Graphene, Nakul Nitin Karle

Open Access Theses & Dissertations

A density functional theory (DFT) study on the geometric and electronic structure of C60 and Sc3N@C80 along with their adsorption on pristine single layer graphene (SLG) is presented. C60 is found to adsorb in two nearly degenerate configurations: (i) with a pentagon facing the SLG, which is the most stable one, and (ii) with a hexagon facing the SLG in a face-to-face perfect alignment, rarely common in Ï?â??Ï? interactions, 0.06 eV higher in energy. The calculated binding energy of 0.76 eV, which includes dispersion effects, is in good agreement with previous theoretical and experimental reports. On the contrary, Sc3N@C80 adsorption …


Bragg Gratings In Polarization Maintaining Optical Fiber As Three Dimensional Strain Sensor, Joel Quintana Jan 2017

Bragg Gratings In Polarization Maintaining Optical Fiber As Three Dimensional Strain Sensor, Joel Quintana

Open Access Theses & Dissertations

Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, electromagnetic interference (EMI) immunity, high sensitivity and multiplexing as compared to conventional electric strain sensors. FBG sensors written within polarization maintaining (PM) optical fiber offer ad- ditional dimensions of strain measurement, greatly reducing the number of sensors needed to properly monitor a structure. This reduction however, adds complexity to the dis- crimination of the sensorâ??s optical response to its corresponding applied strains. This Dissertation defines the set of algorithms needed to measure planar strain using PM-FBGs exclusively. It defines the minimum number …


Electronic Structure Studies On Transition Metal Containing Endohedral Fullerenes, Carbon Onions And Zinc Sulfide Cages, Shusil Bhusal Jan 2017

Electronic Structure Studies On Transition Metal Containing Endohedral Fullerenes, Carbon Onions And Zinc Sulfide Cages, Shusil Bhusal

Open Access Theses & Dissertations

We present the most stable structures for VXSc3-XN@C2n (where X=1-3 and 2n=70, 76, 78 and 80) using a systematic procedure that involves all possible isomers of the host fullerene cages. Subsequently, a detailed investigation of structural and electronic properties of the lowest energy isomers is performed using density functional theory in combination with large polarized Gaussian basis sets. The search procedure developed involved structural optimizations of thousands of fullerenes and correctly identifies the experimentally observed VSc2N@C80 and V2ScN@C80 isomer as the most stable structures. The structural analysis shows that a few V-doped endohedral fullerenes do not follow the isolated pentagon …