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Optical Properties of Single Nanoparticles and Two-dimensional Arrays of Plasmonic Nanostructures
Title
Optical Properties of Single Nanoparticles and Two-dimensional Arrays of Plasmonic Nanostructures.
Creator
Zhou, Yadong, Zou, Shengli, Harper, James, Zhai, Lei, Chen, Gang, Zheng, Qipeng, University of Central Florida
Abstract / Description
The tunability of plasmonic properties of nanomaterials makes them promising in many applications such as molecular detection, spectroscopy techniques, solar energy materials, etc. In the thesis, we mainly focus on the interaction between light with single nanoparticles and two-dimensional plasmonic nanostructures using electrodynamic methods. The fundamental equations of electromagnetic theory: Maxwell's equations are revisited to solve the problems of light-matter interaction, particularly...
Show moreThe tunability of plasmonic properties of nanomaterials makes them promising in many applications such as molecular detection, spectroscopy techniques, solar energy materials, etc. In the thesis, we mainly focus on the interaction between light with single nanoparticles and two-dimensional plasmonic nanostructures using electrodynamic methods. The fundamental equations of electromagnetic theory: Maxwell's equations are revisited to solve the problems of light-matter interaction, particularly the interaction of light and noble nanomaterials, such as gold and silver. In Chapter 1, Stokes parameters that describe the polarization states of electromagnetic wave are presented. The scattering and absorption of a particle with an arbitrary shape are discussed. In Chapter 2, several computational methods for solving the optical response of nanomaterials when they are illuminated by incident light are studied, which include the Discrete Dipole Approximation (DDA) method, the coupled dipole (CD) method, etc. In Chapter 3, the failure and reexamination of the relation between the Raman enhancement factor and local enhanced electric field intensity is investigated by placing a molecular dipole in the vicinity of a silver rod. Using a silver rod and a molecular dipole, we demonstrate that the relation generated using a spherical nanoparticle cannot simply be applied to systems with particles of different shapes. In Chapter 4, a silver film with switchable total transmission/reflection is discussed. The film is composed of two-dimensional rectangular prisms. The factors affecting the transmission (reflection) as well as the mechanisms leading to the phenomena are studied. Later, in Chapter 5 and 6, the sandwiched nano-film composed of two 2D rectangular prisms arrays and two glass substrates with a continuous film in between is examined to enhance the transmission of the continuous silver film.
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Date Issued
2018
Identifier
CFE0007117, ucf:51943
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007117
Catalyst Design and Mechanism Study with Computational Method for Small Molecule Activation
Title
Catalyst Design and Mechanism Study with Computational Method for Small Molecule Activation.
Creator
Liu, Muqiong, Zou, Shengli, Harper, James, Dixon, Donovan, Chen, Gang, Feng, Xiaofeng, University of Central Florida
Abstract / Description
Computational chemistry is a branch of modern chemistry that utilizes the computers to solve chemical problems. The fundamental of computational chemistry is Schr(&)#246;dinger equation. To solve the equation, researchers developed many methods based on Born-Oppenheimer Approximation, such as Hartree-Fock method and DFT method, etc. Computational chemistry is now widely used on reaction mechanism study and new chemical designing.In the first project described in Chapter 3, we designed...
Show moreComputational chemistry is a branch of modern chemistry that utilizes the computers to solve chemical problems. The fundamental of computational chemistry is Schr(&)#246;dinger equation. To solve the equation, researchers developed many methods based on Born-Oppenheimer Approximation, such as Hartree-Fock method and DFT method, etc. Computational chemistry is now widely used on reaction mechanism study and new chemical designing.In the first project described in Chapter 3, we designed phosphine oxide modified Ag3, Au3 and Cu3 nanocluster catalysts with DFT method. We found that these catalysts were able to catalyze the activation of H2 by cleaving the H-H bond asymmetrically. The activated catalyst-2H complex can be further used as reducing agent to hydrogenate CO molecule to afford HCHO. The mechanism study of these catalysts showed that the electron transfer from electron-rich metal clusters to O atom on the phosphine oxide ligand is the major driving force for H2 activation. In addition, different substituent groups on phosphine oxide ligand were tested. Both H affinity of metal and the substituent groups on ligand can both affect the activation energy.Another project described in Chapter 4 is the modelling of catalyst with DFT. We chose borane/NHC frustrated Lewis pair (FLP) catalyzed methane activation reaction as example to establish a relationship between activation energy and catalysts' physical properties. After performing simulation, we further proved the well-accepted theory that the electron transfer is the main driving force of catalysis. Furthermore, we were able to establish a linearivrelationship for each borane between activation energy and the geometrical mean value of HOMO/LUMO energy gap (?EMO). Based on that, we introduced the formation energy of borane/NHC complex (?EF) and successfully established a generalized relationship between Ea and geometrical mean value of ?EMO and ?EF. This model can be used to predict reactivity of catalysts.
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Date Issued
2018
Identifier
CFE0007343, ucf:52112
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007343
Remediation of chlorinated alkanes by zero valent iron with vitamin B12 and Utilization of a modified Gradual Release of Responsibility model in a large enrollment chemistry course
Title
Remediation of chlorinated alkanes by zero valent iron with vitamin B12 and Utilization of a modified Gradual Release of Responsibility model in a large enrollment chemistry course.
Creator
Lapeyrouse, Nicole, Yestrebsky, Cherie, Beazley, Melanie, Chen, Gang, Rex, Matthew, Randall, Andrew, University of Central Florida
Abstract / Description
The following dissertation looks at addressing environmental contaminants in the environment and the integration of an active learning style in an introductory chemistry course. It begins with addressing the concern for chlorinated propanes and ethane in the environment and the importance of looking into environmental remediation applications. This research looks at incorporating vitamin B12 as an environmentally friendly catalyst in the presence of zero valent iron for the reduction of...
Show moreThe following dissertation looks at addressing environmental contaminants in the environment and the integration of an active learning style in an introductory chemistry course. It begins with addressing the concern for chlorinated propanes and ethane in the environment and the importance of looking into environmental remediation applications. This research looks at incorporating vitamin B12 as an environmentally friendly catalyst in the presence of zero valent iron for the reduction of chlorinated propanes and ethane. Chapter 2 presents the analytical methods and conditions in which samples were run. The results from these experiments are discussed in length in Chapter 3. Our results confirmed the hypothesis that vitamin B12 could act as an electron mediator to facilitate the reduction of the chlorinated propanes and ethane. Degradation was examined by observing the formation of byproduct peaks and the release of free chloride into solution. In Chapter 4, vitamin B12 is integrated into an already established industrial application technique, emulsified zero valent iron, and we observed the degradation of 1,2,3-trichloropropane with the formation of byproducts as the reaction progressed. In Chapter 5, this section of the dissertation focused on chemical education and observing an active learning technique in a fundamental chemistry course. The following study was designed to increase students' positive attitude, engagement, and responsibility in a large enrollment chemistry course by utilizing a modified Gradual Release of Responsibility (GRR) model. GRR progressively transfers responsibility from the instructor to the student, allowing students to be more independent and helping them to address atypical problems. Students were assessed using iClickers to monitor their understanding and engagement, as well as surveys to determine their attitudes regarding this specific style of teaching. The results from this study demonstrated that implementing the GRR teaching style had a positive effect on student academic performance and shows the importance of using an active teaching model in a large enrollment course.
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Date Issued
2018
Identifier
CFE0007759, ucf:52373
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007759
Engineering Noble-metal Nanostructures for Biosensing Applications
Title
Engineering Noble-metal Nanostructures for Biosensing Applications.
Creator
Ye, Haihang, Xia, Xiaohu, Kuebler, Stephen, Chen, Gang, Beazley, Melanie, Feng, Xiaofeng, University of Central Florida
Abstract / Description
The ability to engineer noble-metal nanostructures (NMNSs) in a controllable manner and to understand the structure-dependent properties greatly boost our knowledge in rational design of biosensing technologies. In particular, as a type of highly efficient peroxidase mimics, NMNSs hold promising potential to break through the bottleneck of conventional enzyme-based in vitro diagnostics.During the time of my Ph.D. study, I have successfully: 1) directed a two-step method involving seed...
Show moreThe ability to engineer noble-metal nanostructures (NMNSs) in a controllable manner and to understand the structure-dependent properties greatly boost our knowledge in rational design of biosensing technologies. In particular, as a type of highly efficient peroxidase mimics, NMNSs hold promising potential to break through the bottleneck of conventional enzyme-based in vitro diagnostics.During the time of my Ph.D. study, I have successfully: 1) directed a two-step method involving seed-mediated growth and chemical etching for the synthesis of Ru nanoframes (RuNFs) with face-centered cubic crystal phase and enhanced catalytic activities; 2) demonstrated, for the first time, the inherent peroxidase-like activity of RuNFs as a type of efficient peroxidase mimics, opening up possibilities for their bioapplications; 3) developed an enzyme-free signal amplification technique for ultrasensitive colorimetric assay of disease biomarkers by using Pd-Ir nanooctahedra encapsulated gold vesicles as labels; 4) prepared polyvinylpyrrolidone (PVP)-capped Pt nanocubes with superior peroxidase-like catalytic activity and record-high specific catalytic activity; 5) developed a facile colorimetric method for the detection of Ag(I) ions with picomolar sensitivity by using the PVP-capped Pt nanocubes as the probes; 6) developed a non-enzyme cascade amplification strategy for colorimetric assay of disease biomarkers by taking advantage of the interaction between the Ag(I) ions and PVP-capped Pt nanocubes; and 7) established a highly sensitive colorimetric lateral flow assay platform by using Au@Pt core-shell nanoparticles as the labels that possess both plasmonic and catalytic properties.
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Date Issued
2019
Identifier
CFE0007559, ucf:52626
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007559
The Schr(&)#246;dinger Equation with Coulomb Potential Admits no Exact Solutions
Title
The Schr(&)#246;dinger Equation with Coulomb Potential Admits no Exact Solutions.
Creator
Toli, Ilia, Zou, Shengli, Harper, James, Heider, Emily, Chen, Gang, Schulte, Alfons, University of Central Florida
Abstract / Description
We prove that the Schr(&)#246;dinger equation with the electrostatic potential energy expressed by the Coulomb potential does not admit exact solutions for three or more bodies. It follows that the exact solutions proposed by Fock are flawed. The Coulomb potential is the problem. Based on the classical (non-quantum) principle of superposition, the Coulomb potential of a system of many particles is assumed to be the sum of all the pairwise Coulomb potentials. We prove that this is not accurate...
Show moreWe prove that the Schr(&)#246;dinger equation with the electrostatic potential energy expressed by the Coulomb potential does not admit exact solutions for three or more bodies. It follows that the exact solutions proposed by Fock are flawed. The Coulomb potential is the problem. Based on the classical (non-quantum) principle of superposition, the Coulomb potential of a system of many particles is assumed to be the sum of all the pairwise Coulomb potentials. We prove that this is not accurate. The Coulomb potential being a hyperbolic (not linear) function, the superposition principle does not apply.The Schr(&)#246;dinger equation as studied in this PhD dissertation is a linear partial differential equation with variable coefficients. The only exception is the Schr(&)#246;dinger equation for the hydrogen atom, which is a linear ordinary differential equation with variable coefficients. No account is kept of the spin or the effects of the relativity.New electrostatic potentials are proposed for which the exact solutions of the Schr(&)#246;dinger equation exist. These new potentials obviate the need for the three-body force interpretations of the electrostatic potential.Novel methods for finding the exact solutions of the differential equations are proposed. Novel proof techniques are proposed for the nonexistence of the exact solutions of the differential equations, be they ordinary or partial, with constant or variable coefficients. Few novel applications of the established approximate methods of the quantum chemistry are reported. They are simple from the viewpoint of the quantum chemistry, but have some important aerospace engineering applications.
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Date Issued
2019
Identifier
CFE0007733, ucf:52422
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007733
Split Aptameric Turn-On Fluorescence Sensor for Detection of Sequence Specific Nucleic Acid
Title
Split Aptameric Turn-On Fluorescence Sensor for Detection of Sequence Specific Nucleic Acid.
Creator
Kikuchi, Nanami, Kolpashchikov, Dmitry, Zhai, Lei, Chumbimuni Torres, Karin, Chen, Gang, Teter, Kenneth, University of Central Florida
Abstract / Description
Nucleic acid amplification tests (NAATs) enable sensitive detection of low density infections that microscopy and rapid diagnostic test are not capable of detecting. They enable quantitative and qualitative nucleic acid detection, genotype analysis, and single nucleotide polymorphism (SNP) detection. Current state of the art molecular probes used with NAATs includes molecular beacon (MB), Taqman and its variations. This work presents novel molecular probe designed from Spinach and Dapoxyl...
Show moreNucleic acid amplification tests (NAATs) enable sensitive detection of low density infections that microscopy and rapid diagnostic test are not capable of detecting. They enable quantitative and qualitative nucleic acid detection, genotype analysis, and single nucleotide polymorphism (SNP) detection. Current state of the art molecular probes used with NAATs includes molecular beacon (MB), Taqman and its variations. This work presents novel molecular probe designed from Spinach and Dapoxyl aptamers. The aptamers are split into two parts (split aptamer), allowing greater sensitivity and selectivity towards fully complementary nucleic acid analyte. The major advantage of split aptamer probe over state-of-the-art fluorescent probes is its high selectivity: in the presence of a single base mismatched analyte, it produces only background fluorescence, even at room temperature. SSA is a promising tool for label-free analysis of nucleic acids at ambient temperatures.Split spinach aptamer (SSA) probes and split dapoxyl aptamer (SDA) for fluorescent analysis of nucleic acids were designed and tested. In both split aptamer design, two RNA or RNA/DNA or DNA strands hybridized to a specific nucleic acid analyte and formed a binding site for fluorescent dye, which was accompanied by up to 270-fold and 69-fold increase in fluorescence. SSAr consisted entirely of ribonucleotides which potentially be expressed in live cells and used for imaging of specific mRNAs. For in vitro RNA/DNA analysis, SDA consisting of entirely DNA are preferable due to greater chemical stability, lower synthetic cost and reduced ability to form intramolecular structures. Additionally, we designed two DNA strands that function as an adapter for SSA and demonstrated how a single universal spinach aptamer (USSA) probe can be used to detect multiple (potentially any) nucleic acid sequences. USSA can be used for cost-efficient and highly selective analysis of even folded DNA and RNA analytes, as well as for the readout of outputs of DNA logic circuits.
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Date Issued
2018
Identifier
CFE0007031, ucf:51976
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007031